BLM LIBRARY 88072704 > < r for Pinyon - Juniper -r ,;v Woodlands /£>b! Part A ECOLOGY OF THE PINYON- JUNIPER TYPE OF THE COLORADO PLATEAU AND THE BASIN AND RANGE PROVINCES QH OF LAND MANAGEMENT — UTAH AGRICULTURAL EXPERIMENT STATION 541.5 .76 M2 61 1966 BLM Library Denver Federal Center Bldg. 50. OC-521 RO. Box 25047 Denver, CO 80225 r r> 15^0^2 ^ ofc( <5? K 5L\\ • 5 Sc M%C l “iCG \J. I MANAGEMENT ALTERNATIVES FOR PINYON- JUNIPER WOODLANDS A. Ecological Phase: "The Ecology of the Pinyon- Juniper Type of the Colorado Plateau and the Basin and Range Provinces" T. W. Daniel, Professor of Forestry R. J. Rivers, Forester H. E. Isaacson, Range Conservationist E. J. Eberhard, Range Conservationist A. D. LeBaron, Economist A cooperative project of the Bureau of Land Management and the Utah Agricultural Experiment Station Logan July 1, 1966 PREFACE The genesis of the research reported in this volume and in the volume entitled "Economics of Pinyon-Juniper Management," was in the deliberations of Dr. Russell Lloyd (formerly Chief, Branch of Range Studies, Bureau of Land Management) and Dr. N. K. Roberts, then chairman, Center for Social Science Research on Natural Resources, Utah State University. Early in April, 1963, the Bureau of Land Management formally requested the Director of the Utah Agricultural Experiment Station to explore the possibility of developing and conducting a project leading to better management of pinyon- juniper woodlands. Five objectives were originally spelled out by the Bureau of Land Management: (a) to develop ecological criteria for classification of pinyon- juniper sites; (b) to develop the minimum essential ecological data needed for management under various alternatives; (c) to clearly identify the multiple products of woodland ranges and to determine the competitive - complementary - supplementary relationships among them; (d) to assess economic value of the multiple products; and (e) to make an economic analysis of the various management alternatives and woodland uses on the major sites. A memorandum of understanding was signed in the middle of June, 1963 and a project work plan, drawn up by Dr. Roberts and Dr. T. W. Daniel, (Forest Science Department, Utah State University) was adopted later that summer. Dr. Roberts was the over-all project coordinator; Dr. Daniel was the ecological phase leader; in December 1964, Dr. A. LeBaron was made economics phase leader. This volume reports on objectives a, b and part of c. It is hoped that they have been attained. In any event there can be little doubt about the general results that can be expected from reliance upon cross-sectional data in any future pinyon- juniper studies; absence of experimental controls makes 2 data interpretation extremely difficult. Nevertheless, a number of interesting and worthwhile relationships have been developed, many of which should have direct application in management practices. Authors of the various sections in this volume are indicated in the appropriate sub-headings. The contribution made to the successful completion of this project by the three Bureau of Land Management personnel assigned, E. Eberhard , H. E. Isaacson, and R. J. Rivers, is evident from their written work. References are to listings following each section. In addition to the two volumes comprising the project report, attention is directed to the research report submitted by W. Meiners (assigned by the Bureau of Land Management to the ecological team during the first portion of the study) submitted in partial fulfillment of the requirements for a Master's Degree granted Utah State University, June 1965, entitled: "Some Geologic and Edaphic Characteristics Useful to Management Programming Within the Pinyon- Juniper Type". Except for Section 1 and Section. 4 (parts A and B) the entire, contents of this volume were edited by Dr. Allen LeBaron. Office records obtained by the economics group from various land manage¬ ment agencies are linked to control sites visited (Section 7) but there may be inaccuracies both as to project identification and treatment practice, some instances the apparent treatment was at variance with office records: areas supposedly seeded were barren o if introduced species, machinery appeared to have been used in areas reported as hand -chopped , what were clearly tree- control areas were identified by agency personnel as spraying projects, e All ecological plots are thought to have been located accurately t the quarter-section, but difficulty was still encountered in determining spec . -.c projects visited. It may seem that there are anomalies in the numbers of plot locations reported in the various sections to follow. Actually this is not the c In most instances tree, soil, and understory vegetation data were cohec ed 3 from every plot. But sometimes circumstances dictated the need for only soil and forage data or for certain tree measurements. Thus, while something like 430 separate sites were visited, only slightly over 400 tree or soil plots are reported; information was obtained from about 390 grass plots. The frontispiece is a map illustrating the approximate locations where ecological data were gathered during the course of this study. Many of these locations are on or adjacent to pinyon- juniper control and reseeding sites, but unfortunately these cases cannot be illustrated on such small scale . Dr. E. B. Wennergren, Director Economic Research Institute Utah State University 4 Table of Contents Section Page Preface 2 1„ Ecological Phase. Acknowledgements and Introduction 13 2. Field Methods 17 2„au Forest Data 17 2. b„ Range Data 2, Co Soil and Site Data 21 3o Description of Ecological Provinces Within the. Study Area 27 3, a» Literature Review 27 3„b„ Description of the Area 28 3,c, Geology and Physiography 30 J,d3 Climate 32 3 » e, „ Soils 36 3. f. Vegetation 41 4, Site. Classification of the Pinyon- Juniper Woodlands 55 4. a. Pinyon Site Index Curves 56 4. b. Height -Age and Diameter' -Age. Curves by Site Indices, Species 60 and Provinces 4. c. Tree. Height -Crown Diameter and Site Index Correlations 68 5. Relationship of Soil, and Climatic Factors to Pinyon Site. 95 Classification 3 .a. Choice of Site factors 95 5. b<, Statistical Analysis of Soil Plot and Climatic Data ^06 5. C., Chemical Properties and Site, Productivity 113 6, Woodland Characteristics and Tree Control 125 6. a. Percentage Kill-Tree Di.amet.--r: Correlation 128 6 „ b , Direct Growth Responses I33 6ac, Conversion Site "Longevity M I35 7. Range. Evaluation of Pinyon- Juniper Stands and Tree Conversion 16 3 Projects 7. a. Herbage Produc. t ion- Percent free Canopy Relationships 164 7.b. Bunch Grass — Short Grass: R. lationship to Tree Cover 164 7 . c. Variation in Grass Production Associated With Conversion 169 Methods 7.d. Grass Production/Site Factors by Major Conversion Treatment 189 7 „ e. How Tree Removal. Affects Amount of Useable Acreage 196 8. Conversion Decision: Recommendations 201 8. a. General Considerations When Choosing Conversion Sites 201 8.b. Treatment Choice by Province 202 8.c. Precipitation Recommendations by Province 205 8.d. Soil Factor Recommendations 209 8. e. Tabulated Recommendations 210 9. Volume Tables and Tree Products 217 9. a. Volume Tables 217 9.b. Characteristics and Growth Trends of Pinus Monophylla 221 Christmas Trees 9. c. Tree Products Other Than Christmas Trees 223 10. Inventory Techniques 231 10. a. Suggested Woodland Inventory Techniques 231 10. b. Range Inventory in Pinyon-Juniper Woodlands: A Suggestion 235 6 List of Tables Section Page 3.e.l. Percent of soil observations as classified in the new 41 soil classification system. 3.f.l, Average composition percentage and consistency of woodland 45 tree species of the Escalante-Sevier province, and sub- province breakdown. 3.f.2, Average composition percentage, and consistency of woodland 47 tree species of the La Sal province and subprovince break¬ down. 3, f„3, Average composition percentage and consistency of woodland 49 tree, species of the Coronado province and subprovince break¬ down. 4. c.l. Pinyon sp. height /crown diameter regression formulas. 87 4. c,2. Juniper sp. height /crown diameter regression formulas. 87 5. b,l. Step-wise regression analysis, 1964 plots, 107 5.b.2, Summary: Residual variables, 1964 plots, 108 5,b,3. Summary: Residual variables Escalante-Sevier province, 109 1964-65 plots. 5.b,4, Summary: Residual variables La Sal province, 1964-65 plots. 109 5. b„5. Summary: Residual variables Coronado province, 1964-65 110 plots „ 6. a l. Suggested form for collecting potential tree kill data, 132 6 . a, 2. Percent: of stand above 7" necessary to achieve a given kill level o 6 . b , 1 . Diameter characteristics •'-residual, trees (85 plots), 134 6. b. 2. Growth response of residual trees following tree control. 6.c.l. Pinyon spp, tree height /agt regression analysis. i^2 6.C.2, Juniper spp, tree height /ag* regression analysis, 6, c.3. Eradication plot summaries. 156 6., c,4. Kill and slash summary by treatment, 160 7. c.l, Projects in the Escalante-Sevier province that were chained but not seeded. 7 \ . 175 7.c.2. Projects in the Escalante-Sevier province that were broadcast with introduced species and chained. 7.C.3. Projects in the Escalante-Sevier province that were chained, 176 cleared and drilled. 7.C.4. Projects in the La Sal province that were chained but not 178 seeded . 7.C.5. Projects in the La Sal province that were broadcast with 179 introduced species and chained. 7.c.6. Projects in the La Sal province that were chained, cleared 182 and drilled. 7.C.7. Projects in the Coronado province that were chained but not 183 seeded . 7.C.8. Projects in the Coronado province that were broadcast with 185 introduced species and chained. 7.c.9. Projects in the Coronado province that were chained, cleared 187 and drilled. 7.C.10. Comparison of two seeding treatments, broadcast-chain and 188 clear-drill at the same sites. 7.d.l. Dependent and independent variables used in multiple 190 regressions by province. 7.d.2. Partial correlations of residual variables with seeded grass production. a. Escalante-Sevier. 191 b. La Sal. 192 c. Coronado 192 7.d.3. Residual variables and regression coefficients for selected control practices. a. Escalante-Sevier. 193 b. La Sal. 193 c. Coronado. 193 7.d.4. Estimating equations for forage response. 194 7.d.5. Chi-square test of Escalante-Sevier estimating equation 196 employing 1964 data. 7. d.6. Listing of regression variables used singly or in combination. 198 8. C.I. Common species of the Escalante-Sevier province. 206 8.C.2. Common species of the La Sal province. 207 8 8 . c .3 . Common species of the Coronado province. 208 8 . e . 1 . Recommendations for seeding pinyon- juniper stands in the Escalante -Sevier province. 211 8 . e . 2 . 4 Recommendations for seeding pinyon- juniper stands in the La Sal province. 212 8 . e. „ 3 , Examples of low, fair and high production grass stands the Escalante-Sevier province- -drill ing . in 213 8 . e . 4 . Examples of low, fair and high production grass stands the La Sal province--broadcasting. in 214 8 . e . 5. Examples of low, fair and high production grass stands the Coronado province- -broadens ting. in 215 9. a. 1. Pinyon volume tables (cubic feet). 219 9 , a. 2 , Pinyon volume tables (cords). 219 9 . a. 3 . Juniper volume tables (cubic feet). 220 9 . a. 4 . Juniper volume tables (cords). 220 9 . b . 1 . Periodic growth increment of 45 pinus mono phy 1.1a Christmas trees , 223 9 . c . 1 . Pinyon sp. height /diameter regression analysis. 224 9.c.2. Juniper sp, height /diameter regression analysis. 226 9 . c . 3 , Product -age relationships for three site indices. 228 1 0 j 3 8 1 . Suggested classification of P-J lands by management, alternatives . 232 1 0 , a „ 2 . Pinyon sp, relationships. 234 10. a. 3 . Juniper sp, relationships. 234 10, a 4, Suggested inventory management symbols. 235 1 0 . b . 1 . Listing of crown closure /product ion estimates. 240 9 a List of Illustrations Section Vage Frontispiece: Approximate locations of study plots 3.b.l. Boundaries of the 3 ecological provinces based upon differences 29 in geology, topography, climate, soil and vegetation. 3.c.l. View of Escalante-Sevier woodland. 33 3.c.2. View of La Sal woodland. 33 3.c.3. View of Coronado woodland. 33 3. d.l. Hythergraphs for the 3 ecological provinces. 37 4. a.l. Site tree form follows growth pattern of younger trees. 57 4. a. 2. Site tree form agrees with "flattened” growth curve. 57 4. a. 3. Site tree form holds height below "flattened" growth curve. 57 4. a. 4. Pinyon site indexes. 61 4. a. 5. Juniper site indexes. 63 4. a. 6. Pinyon/Juniper height relationships. 65 4.b.l. Pinyon height/age (province 2). 69 4.b.2. Pinyon height/age (provinces 1 and 3). 71 4.b.3. Pinyon diameter/age (provinces 1, 2, 3). 73 4.b.4. Juniper height/age (province 2). 75 4 . b . 5 . Juniper height/age (provinces 1 and 3). 77 4.b.6. Juniper diameter/age (province 1). 79 4.b.7. Juniper diameter/age (province 2). 81 4. b . 8 . Juniper diameter/age (province 3). 83 4.c.l. Pinyon height/crown diameter for two site classes (all 89 provinces) . 4.C.2. Pinyon height/crown diameter for three site classes (all 90 provinces) . 4.C.3. Juniper height/crown diameter for two site classes (province 1). 91 4.c.4. Juniper height/crown diameter for two site classes (province 2). 92 10 4. Co 5. Juniper height/crown diameter for two site classes (province 3). 93 5. C.I. Example of site graph. 117 6. a.l, Kill and one-way chaining, 129 4 6. a. 2, Kill and two-way chaining, 130 6. a, 3. Kill and cabling. 131 6.b„l. Apparent "release" in a juniperus osteosperma disc. 137 6,c.l, Pinyon height/age curves (all provinces), 139 6,c,2. Juniper height /age curves (all provinces). 140 6,c.3. Crown conversion chart 141 6.C.4, Pinyon longevity prediction. a. 24' - 31' sites. 144 b, 18' - 23' sites, 145 Co 11' - 17' sites. 146 6,c.5. Juniper longevity prediction (province 1). a, 24' - 31' site, 147 b, 18' - 23' site, 148 c, 11' - 17' site, 149 6,c,6, Juniper longevity prediction (province 2) a„ 24 ' - 31' site. 150 b, 18' - 23' site, 151 c. 11' - 1.7 ' site, 152 6,c,7. Juniper longevity prediction (province 3) a. 24' - 31' site, 153 b, 18' - 23' site. 154 Co 11' - 17' site 8 155 6. C.8, Intact tree crown slash and protected forage. a, 8% cover (initial control 1959). 161 bo 28% cover (initial control 1956). 161 7„a,l., Grass production for various tree canopies--Escalante-Sevier . 7. a, 2, Grass production for various tree canopies --La Sal. 165 7. a. 3. Grass production for various tree canopies--Coronado , 166 7.b,lo Native short grass is never found directly under trees. 166 1.1 168 7.b.2. Squirreltail growing in 4 inches of litter on a Nevada pinyon- juniper site. 7.b.3. Sandberg bluegrass growing in 2 inches of litter on a Nevada 168 site . 7.b.4. Native bunchgrass looks vigorous growing in litter under a 168 dead pinyon. 9.c.l. Pinyon height/diameters (all provinces). 225 9.c.2. Juniper height/diameters (all provinces). 227 10. a. 1. Pinyon height/age curves. 236 10. a. 2. Juniper height/age curves. 237 10. a. 3. Pinyon height/diameter . 238 10. a. 4. Juniper height/diameter. 239 lO.b.l. Example Potential grass production (24' - 31' juniper sp. , 241 province 2) . 12 1. ECOLOGICAL PHASE ACKNOWLEDGEMENTS AND INTRODUCTION T. W. Daniel, Ecology Phase Leader 4 The pinyon- juniper type covers an area of approximately 60,000,000 acres in western United States with the majority of the type occurring within the five state study area. Pinyon- juniper sites are the transition zones between the shrubs and grasslands at lower elevations and the commercial types or mountain browse type at higher elevations. Differences in rainfall and soil texture patterns account for the boundaries between the zones. The pinyon- juniper type is associated with a rainfall total of between 10-17 inches and at minimum rainfall occurs on coarse textured soils. The transi¬ tional pinyon- juniper has been neglected in an effort to answer problems or to exploit the resources of the more valuable cover types above and below it. The Bureau of Land Management^ awareness of the lack of information for the proper management of the pinyon- juniper type resulted in a request for a study investigating the economic and ecologic factors involved in evaluating various management alternatives. Keith Roberts, in collaboration with T. W. Daniel drew up the requested project proposal. It was accepted and financed by the Bureau as a cooperative project with the Utah State Univer¬ sity Agricultural Experiment Station. In addition to a grant to the Experi- 4 ment Station, three Bureau personnel were assigned to the ecology team for a period of three years. A project as broadly based and fundamental as a study of the pinyon- juniper type was of interest to all the land management agencies within the study area. These agencies contributed advice and data on which the field work was initiated. The Bureau of Land Management was actively represented in the planning by R. D. Lloyd, Edwin Zzidlicz, Myrvin E. Noble, Archie D. 13 Crafts, R. D. Nielsen, and H. E. Jones as well as by the BLM men assigned to the study. The Forest Service contributed through Joel Frykman, C. A. Wellner, 0. C. Olson, A. P. Caporaso, S. S. Hutchings and D. E. Parker. A considerable body of data as well as advice was obtained from C. T. Prout Jr., K. Hugie, E. Olsen, Lamar Mason and Erasmus Williams of the Soil Conservation Service. Several staff members of Utah State University assisted the ecological work through advice, laboratory facilities, and statistical procedures and analysis. The major University contributors were C. W. Cook, Rex Hurst, R. W. Miller, J. P. Thorne, N. E. West, and R. R. Moore. District Managers and their personnel of the BLM were helpful in advancing the aims of the project with their contributions of time and materials, and in response to emergency situations. Phillip Solenberger and W. E. Meiners were initially assigned to the project and contributed to its successful conclusion. The Forest Science Department students, whose assistance in the field work during the summer months was very important, were Gerhard Glatzel, G. A. Landrum, and Philip Unterschuetz the first summer, and T. R. Meyer and W. K. Rother the second summer. Richard Marasco and Terrance Glover, graduate assistants in the. Department of Agricultural Economics, helped perform statistical analysis of part of the ecological data. In an effort to exploit the. experience and advice of the various government agencies actively involved in the management of the pinyon- juniper type, two meetings were called at which representatives of the Bureau of Land Manage¬ ment, U. S. Forest Service, Soil Conservation Service and the U. S. U. Agricultural. Experiment Station pooled their ideas as to the size of the region to be covered in the limited time, types of data to be collected, and the methods to be used for the collection of the data. The first meeting was in Salt Lake City on August 22, 1963, and the consensus was that the study should be an extensive survey covering the Colorado Plateaus and the 14 Basin and Range provinces as far south as the Mogollon Rim, Arizona and Soccoro, New Mexico. It was decided that the pinyon- juniper type was more in need of a set of standards that could be applied throughout the region than an intensive survey of a limited area. The second meeting was a two day field trip (September 3 and 4) in the vicinity of Monticello, Utah. Twenty-three men from several land management agencies gathered to discuss field procedures and the problems inherent in trying to get, with a limited sample, an adequate representation of the variations in the type. As the result of these meetings, a considerable body of heterogeneous plot data was gathered from various agencies with the Soil Conservation Service as the predominant source. These data were summarized, and, on the basis of the results, Robert Rivers drew up a questionnaire for submission to all the BLM District Managers in the region. This questionnaire requested the location and description of pinyon- juniper sites of poor, medium and high quality. After receiving the information from the District Managers, Rivers visited every district in order to select sample sites which conformed to the needs of the study. In June, the full ecologic team including three forestry students began the plot measurements. In the course of the field season they visited every BLM district within the study area. In the first year, the field work concentrated on the tree plots and took advantage of burns and eradication sites when suitable tree plots could be located in their vicinity. No special effort was made to locate eradica¬ tions but rather to visit the cross-section of tree-sites selected in the spring. This procedure allowed the economic team a field season for selecting the eradication sites on which the ecologic team was to collect data on the grass production, tree height-diameter curves and soil profile characteristics in the second field season. In the second field season the ecologic team supplemented the tree-plot data of the previous year in order \ 15 A to increase the number of eradications visited at various locations. For the most part, tree plots were established along the margin of an eradication. These tree plots provided additional tree-plot data as well as aided in deter¬ mining the site index of the eradication. In the winter of 1964-65, the first year’s data were analyzed so as to modify field procedures the second year. In the second field season, the early season work was a continuation of the emphasis on tree-plot data collec¬ tion. Later when grass production had reached a peak on areas with the spring developer species, the emphasis shifted to collecting grass produc¬ tion data ort pinyon- juniper eradication and grass seeding projects. During the winter of 1965-66, the data were analyzed for presentation in this report. The ecological conclusions are presented in compartmented units by the individuals who had primary responsibility for the collection and analysis of the data reported. 16 2 . FIELD METHODS 2. a. Forest Data — R. J. Rivers A total of 405 pinyon-j uniper sites were evaluated during the 1964-1965 field seasons. These sites were located throughout the five southwestern states to facilitate determination of the ecological relationships of four major wood¬ land species: Pinus edulis, Pinus mcnophylla, Juniperus osteosperma and Juni- perus monosperma. Some of the areas sampled supported Juniperus scopulorum and Juniperus dippeana, and, although these trees were measured, their eco¬ logical relationships were not studied. During the 1964 field season major emphasis was on woodland site evaluation; during the 1965 season emphasis was placed on tree control/reseeded sites and their adjacent woodland stands. The main criterion for tree plot location was the existence of a mature/ over-mature dominant pinyon or juniper tree. This tree was called the "site tree." The site tree was selected because: (1) it was the tallest tree on the particular site; (2) it was relatively free of stem defects (such as excessive branching) ; (3) it was located where it would not be susceptible to any abnor¬ mal site factors (such as proximity to a water course) . An attempt was made to locate such site trees throughout the various range, soil, and geologic provinces associated with the P-J type. Although the tree plots established during the 1965 field season were located adjacent to tree control projects, emphasis was still placed on locating a mature, dominant tree to serve as a "site tree." Having selected a site tree, a tenth (1/10) acre rectangular plot was estab¬ lished. The plot dimensions were 100" x 43.6'. The site tree was used to reference the uphill side and short axis of the plot center. Woodland data ob¬ tained from each study site included: (a) fixed plot data; (b) variable plot data. 17 Fixed plot data- The following list illustrates the type of data collected for each tree on the fixed plot during each field season: 1964 Diameter at 1' X Diameter at 4 1/2" X Tree height X Crown diameter X Crown height X No. of trees l"-4 1/2" X No. of trees less than 1’ X Comments on tree vigor and form class X 1965 X X No No No X X No Variable plot data- On each site a number of trees, not necessarily located on the fixed plot, running the gamut of various diameter classes, were measured. These were specially selected to avoid multiple stems, deformed, suppressed, or rotted and broken trees. These measurements were used to construct height/dia¬ meter site curves. Disks from the site tree and several other trees in this group were col¬ lected at 1’ diameter to provide enough basic data for height-age and diameter- age relationships. In addition to forest resources data, many "eradication" plots were estab¬ lished in 1965. These 10th acre plots provided information on tree kill, growth rates, and slash cover (Sections 6 and 9). 2.b. Range Data--H. E. Isaacson. Since the main objective of the ecological study was to develop criteria for classification of pinyon-j uniper sites and to establish a basis for recog¬ nition of these sites, all measurements during the 1964 field season were direct¬ ed toward that end. The second field season (1965) differed; emphasis was placed 18 upon collection of vegetational production data from woodland conversion pro¬ jects in an attempt to discover if tree classification may be correlated to suc¬ cess or failure of such projects. Vegetational measurements included: (1) foliage cover of both the tree layer and understory vegetational layer; (2) species composition of the tree canopy and understory; (3) annual production of understory vegetation. The additional measurements made the second year on woodland conversion projects were: (1) understory production on both treated and non-treated area; (2) basal area of grass on both treated and untreated areas. The basic sampling procedures for the 1964 field season was as follows: Tree canopy and species composition were measured along three 100 foot transects at intervals of 1 foot. The initial transect was located parallel to the contour, with the 50 foot mark spaced 15 feet down-slope from the site tree. The succeeding transects were perpendicular to the proceeding one in the form of a U around the site tree. A spherical densiometer [_Lemmon, 1956] was leveled at each foot along the tape and species hits were recorded if tree cover was sighted at the center crossmarks of the instrument.'*’ This information was used to compute species composition of the total tree canopy. If species were not encountered, but trees were present in a tenth-acre plot positioned along the first 100 foot The instrument was not used in accordance with the instructions for meas¬ uring forest overstory, because of the uneven age and height of trees encoun¬ tered in the individual stands and the magnitude of difference in mature tree height between stands (10 feet to 47 feet). It was the only instrument avail¬ able that would offer a close measurement of woodland tree canopy over a specific point along a transect. 19 . — V'Ti transect ^Sec . 2.aJ, they were marked P (present). The percentage contribution made by each understory species to total under¬ story composition was obtained by ocular estimate. The percentage estimates were made within a circular plot (approximately 3/4 acre) formed by a 100 foot radius from the site tree. The lower vegetation layer was generally so sparse that a large area had to be covered to find diversification in species. This was especially true where tree canopy exceeded 30 percent. Trace species were also recorded where species were not outside the plot. At 25 foot intervals along each transect, circular 9.6 square-foot plots were spaced, and annual production of grass, forbs, browse and annuals was estimated by the forage weight-estimate method Frischknecht and Plummer, 1949; Perchanec and Pickford, 1937 . Ten percent of these latter estimates were ran¬ domly selected and checked in the field for green weight and dried for conver¬ sion of green weight to air-dry weights. Whenever tree plots were adjacent to control projects, additional grass production was measured on 20, 9.6 square-foot plots spaced at 25 foot intervals along two parallel transects. These, transects were established on homogeneous sites in conversion areas and 20 comparison plots exhibiting similar site condi¬ tions were spaced within the untreated areas. Where untreated areas were small and did not afford such a large sample, 1.0 plots were used (this was necessary only on projects located on Indian reservations in Arizona). Estimates of grass basal area as a percent of each 9.6 square-foot plot were made. Also the percent of each plot taken up by usable or ungrazable area (debris, fallen trees, rocks, etc.) was estimated. Climatic data from records of Weather Bureau stations located within or close to the pinyon- juniper type were summarized. Physiographic and recent geologic historical information was gathered for the regions studied. 20 2 . c . Soil and Site Data — E. J, Eberhard During the field seasons of 1964 and 1965, soil and site information was collected from 403 plots within the pinyon-j uniper type in Utah, Nevada, western Colorado, northwest New Mexico, and northern Arizona. Soil profile pits were located within tree stands on 351 of these plots, and the remaining 52 pits were located on tree control projects. Since major emphasis during the 1965 field season was on analysis of grass production following tree control, tree plots were located adjacent to control projects whenever possible. An effort was made to select tree and adjacent project plots which were comparable in measured soil and site factors. If soil conditions on the project site were different from those found on the tree plot, a complete soil profile description was made for the project site. In cases where soil and site conditions appeared essentially the same, either an abbre¬ viated soil profile description of the project site was made, or the sites were treated as being identical. The general guide used in measuring various soil and site factors was the Soil Survey Manual [United States Department of Agriculture, 1951]. Soil pit location- On tree sites the soil pit was located down-slope, and usually about five feet from the base of the site tree. Care was taken to avoid areas where run-off water might accumulate or where recent soil deposition or removal had taken place. The face of the pit was located where it was subject to site tree crown influence. Soil pits located on project sites were dug in the areas from which grass production measurements were obtained. Areas where run-off water might accumulate or where recent soil deposition or removal had taken place were avoided. Prior to digging any soil pits, several auger holes were drilled to insure the selection of a representative soil profile for the site. Soil pit depth- Each soil pit was dug by hand to a depth of 5 feet or until bedrock conditions made further digging impossible. For the abbreviated profile descriptions on project sites, the pit was dug to a depth of 18 inches and then a soil auger was used to compare the similarity between the balance of the pro¬ file and the previously described profile in the adjacent tree stand. Slope gradient- Slope was measured in percent with an Abney hand level. Aspect- Slope aspect was measured with a hand compass to the nearest bearing or azimuth degree. Slope character- Slope character was classified as being uniform, undulating, concave, convex, or complex. Slope position- Slope position of every plot was classified as being on either a waxing slope, a waning slope, a free face, or a constant slope. Slope deposition- After a soil pit was completed, the slope deposition was re¬ corded as being material from transported, residual, or colluvial origin. Parent material- From field observations and available geologic maps, the parent material (or parent materials) of each profile was identified by one of the follow- mg classifications: (1) Sand, (2) Loess, (3) Fine alluvium, (4) Coarse allu¬ vium, (5) Tertiary sediments, (6) Lacustrine deposits, (7) Sandstone, (8) Shale, (9) Limestone/dolomite, (10) Acid igneous, (11) Basic igneous, (12) Metamorphic rock, (13) Undifferentiated materials. Soil permeability- An estimate of relative soil permeability was made through a consideration of structure, texture, porosity and cracking within each profile. Permeability was rated as very rapid, rapid, moderate, or slow. Death and thickness of horizons- Once horizons were identified, the depth and thickness of each horizon in a profile were measured and recorded to the nearest one-half inch. 22 Horizon designation- In accordance with procedures outlined in the Soil Survey Manual , an attempt was made, in the field, to give each horizon its appropriate symbol designation. Since this designation was not checked by laboratory measurements, the accuracy achieved may be questioned. Color- Dry and moist color of the soil in each horizon was determined by using the standard color names, and the Munsell notation of color. Texture- Soil texture was determined by the "feel" method. Samples of known texture were checked periodically throughout the field season in an effort to maintain a consistent basis for textural classification. Structure- An estimate of the structural condition of each horizon was made by referring to standard soil structural forms, size of forms, and relative strength of these structural forms. Cons is tence- Both dry and moist consistence of soil in each horizon were esti¬ mated using rating systems found in the Soil Survey Manual . Stickiness and plasticity- These soil physical factors were measured using soil samples containing water slightly in excess of field moisture capacity. Rating systems in the Soil Survey Manual were used in making the recorded estimates. Horizon boundaries- Boundaries between horizons were described in terms of dis¬ tinctness and topography as specified in the Soil Survey Manual . Rockiness or stoniness- A percentage estimate of the volume of each horizon occupied by rocks or stones was made. Gravel was not included in this estimate, but was considered in the textural classification. £H- The pH of each horizon was determined using the standard indicator solutions of phenol red, creosol red, and thymol blue with the color chart of indicators from Clark [1928]. 23 Lime or calcium carbonate- The relative amount of lime in each horizon was deter¬ mined by the reaction of the soil with a 10% HCL solution. Horizons were rated none, weak, moderate, strong, and very strong in lime concentration. The degree of lime cementation in a horizon was rated as being weak, moderate, strong, or indurated. Moisture holding capacity- The total potential moisture holding capacity of each profile was estimated in the field by considering soil texture, rockiness, and profile depth. Ratings of very high, high, moderate, low, or very low were assigned to each soil profile. Roots- The size, relative abundance, and distribution of tree and grass roots encountered in the profile were recorded. An attempt was made to determine if tree roots occupied fractures in bedrock. Location and elevation- The topographic maps printed by the U. S. Geological Survey and prepared by the Army Map Service were used to locate all plots for future reference. These maps, which have a scale of 1:250,000 and a contour interval of 200 feet, were the most up-to-date available for a majority of the study area. Plots were located by township, range, section, and quarter section, where possible. Elevation was recorded to the nearest 100 feet. Collection of soil samples- Approximately one pound of soil for each horizon was collected in plastic bags for later laboratory analysis. From the abbreviated soil pits on the tree control project, only samples of the A1 horizon and the B or AC horizon were collected. Photographs - A photograph showing the site tree and surrounding trees and vegeta¬ tion was taken on each tree plot. A photograph of each tree removal project was also taken. In project photographs, the view-finder was focused on a spot 20 feet from the camera lens to provide some basis for later comparison of grass stands. REFERENCES (1) Clark, William M. 1928. The Determination of Hydrogen Ions, Williams and Wilkins Company, Baltimore. (2) Deming, M. H. 1957. Two phase range condition surveys supplemental instruction for field use, Volume IX Range, Part 10 Studies. Chapter 10.3, Condition Surveys of the Bureau of Land Management Manuel, and Amendments , 4 p . (3) Frischknecht , Neil C. and A. Perry Plummer. 1949. A simplified technique for determining herbage production on range and pasture land. Agron. Jour. 41(2) : 63-65 . (4) Lemmon, P. E. 1956. A spherical densiometer for estimating forest over¬ story density. Forestry Science 2:314-320. (5) Pechanec, J. F. and G. D. Pickford. 1937. A weight estimate method for the determination of range or pasture production. Journal Am. Soc. of Agron. 29(11) 594-904. (6) United States Department of Agriculture. 1951. Soil Survey Manual. Agricultural Handbook 18, Soil Survey Staff, Bureau of Plant Industry, Soils and Agricultural Engineering. 25 3. DESCRIPTION OF ECOLOGICAL PROVINCES WITHIN THE STUDY AREA H. E. Isaacson The study area consisted of portions of five western states: Utah, Nevada, Arizona, New Mexico, and Colorado. This section describes an attempt to sub¬ divide the area into provinces on the basis of ecological similarities. Data are separately analyzed from three tentative provinces demarcated according to the methods and rationale of Franklin [1965]. The provinces are outlined on the map shown as Figure 3.b.l and are titled Escalante-Sevier , La Sal, and Coronado, respectively. 3. a. Literature Review Pinyon-j uniper woodland commonly occupies elevations of 5,000 to 8,000 feet in all five states. It is generally accepted that the lower limit of the wood¬ land type is restricted by deficient moisture [Pearson, 1931] or finer valley soils [Woodbury, 1947; Meiners, 1965]. Junipers appear to be invading sagebrush and grass types adjacent to the lower altitudinal limit. This may be the result of decreased fires and increased grazing [Stoddart and Smith, 1955] . The upper edge of the woodland belt grades sharply into either Ponderosa pine (Arizona and parts of Colorado and New Mexico) or a mountain browse zone (Colorado, Utah, and Nevada) . The ecotone is almost always narrow, 200-300 linear feet [Woodbury, 1947; Rasmussen, 1941; and Merkle, 1952], At the upper altitudinal limit, Pinyon and Juniper are confined to the warmest parts of the topography [Phillips, 1909; Pearson, 1931; Rasmussen, 1941; Daubenmire, 1943; and Richmond, 1962]. Junipers appear to establish first on all the recently invaded sites. Old Juniper trees in a mixed stand still have the characteristic shape of open-stand 27 trees. Woodbury [1947] notes evidence in plots located on the Arizona Black Mesa that pinyons have a tendency to follow junipers in the invasion of new areas. This succession seldom follows to the lower altitudinal limits of the usual juni¬ per codominant. Woodbury [1947] emphasizes that distribution limits at either the upper or lower edges or at the discontinuities within the pinyon-j uniper woodland at given locations are not necessarily set by climate alone but by the interaction of all agencies involved, climate, soil, soil moisture, and biota. The general locations may fit the climatic pattern, but the details of the limits result from the inter¬ actions of many factors. These factors do not remain constant over such a broad expense as is covered in this study. A variety of habitats result from different environmental condi¬ tions. In the Pacific Northwest, Franklin [1965] divided the true fir-hemlock forest into managable units based upon geologic, topographic, climatic, edaphic and vegetational characteristics. He considered the units ecological provinces because of the several factors used for regional breakdown. This appeared to be a useful approach in establishing divisions in the pinyon-j uniper study area. 3.b. Description of the Area Sampling was limited to the Great Basin and the Colorado Plateau physio¬ graphic provinces [Fenneman, 1931]. This encompasses a portion of the five states already mentioned. Pinyon-j uniper woodlands occupy extensive areas at middle elevations in the study area. These woodlands occur in areas with widely diver¬ gent geologic histories, topography, and climatic conditions. Within the sam¬ pling area, there is also considerable variation in botanical composition both for trees and understory. Thus, there is a need to subdivide this vast woodland area into ecologically consistent units. The ecological province boundaries drawn in Figure 3.b.l are confined to the heart of the pinyon-j uniper type in 28 Figure 3.b„l. Boundaries of provinces based on vegetation composition alone . 29 the two physiographic provinces. Division boundaries are considered firm, but outer boundaries may extend further depending upon characteristics of vegetation and environment. 3.c. Geology and Physiography The Escalante-Sevier ecological province largely corresponds with the eastern portion of Fennemann’s [1931] Great Basin Section of the Basin and Range Physiographic province occurring from the Wasatch front westward to longitude 115 degrees. However, a slight change is made on the southeast boundary and a portion of the high plateaus and Grand section of Utah is incorporated with this ecological province. Noland [1943] provides an abbreviated geologic history which produced the present relief of the province. The Paleozoic and later structural history leads to the suggestion that these events have been integral parts of a single orogenic cycle, during which the initial geosynclinal downwarping was successively followed by one or more broad geoant iclinal uplifts, the last of which culminated in an epoch of folding and overthrusting, and a final stage of block faulting. Faulting appears to have been started at least by early Oligocene time and to have continued up to the present day. Prior to the faulting, a more intense deformation of folding and overthrusting took place in the Mesozoic and early Tertiary period. Internal drainage throughout the province is typified by accumulated allu¬ vium in low valleys brought down from mountains altered by erosion. The topo¬ graphy consists of isolated mountain ranges (largely fault block mountains) separated by aggraded desert plains. Valley deposits are often very deep and are generally unconsolidated. The ranges are commonly parallel in a general north-south orientation and extend to 50 and 75 miles in length. According to Fenneman [1931] the rocks which compose the mountains are largely sedimentary, 30 being older than Cretaceous age. Some ranges consist partly or wholly of igneous rocks. Characteristic of middle elevations where mountain slopes grade into the plains are rock pediments, either covered by a deep alluvial fan or thin soil mantle. At the intermediate elevations, pinyon and juniper are found on the pedi¬ ments and steeper foothill slopes. Sampling was restricted to the gentle slopes (2 to 15 percent); i.e., to the pediments and low sloping hills between 5,000 and 8,000 feet. Both the La Sal and Coronado ecological provinces occur within the Colorado Plateau physiographic province of Fenneman [1931]. Portions of three sections of the province, Uinta Basin, Canyon Lands, and High Plateaus of Utah, form the La Sal ecological province. The Coronado ecological province comprises Fenne- man's Navajo, Grand Canyon and Datil sections. The La Sal ecological province is drained by the Colorado, Green, and San Juan Rivers, the Coronado by the Little Colorado and Colorado Rivers. Hunt [1956] furnishes a concise geologic history of the Colorado Plateau. In pre-Cenozoic time, the Plateau province had been a shelf area. In pre- Cretaceous age and during the early Tertiary, the Plateau area was a basin or trough probably not far above sea level and surrounded by newly-formed mountains whose higher parts were subjected to glacial, or periglacial condi¬ tions. The trough, or basin, was the product of folding that began in late Cretaceous time and continued into early Tertiary time. In its lower parts, several thousand feet of lacustrine and fluviatile sediments were deposited. After Eocene time conditions changed markedly. Aggradation ceased and general degradation began; igneous activity, in the form of volcanism and intrusions, became extensive; there was extensive faulting, especially along the west and south edges of the Province; and epeirogenic uplift began. The erosion, igneous activity, faulting and uplift have continued to the present day. 31 Colorado Plateau deposits of early Cenozoic age are well represented on, or adja¬ cent to, the Colorado Plateau; but deposits of late Cenozoic are are scarce, thus late Cenozoic geologic history is not too well known. In adjoining parts of the Basin and Range province the reverse is true; these deposits of early Tertiary age are scarce but deposits of late Tertiary age are extreme. Present-day characteristics of the Colorado Plateau are described by Fenneman [1931] . The first distinguishing feature is approximate horizontality of its rocks. In the contiguous provinces the strata are folded. Tilted beds are limited to a few great monoclines and the borders of a few local uplifts. There is no lack of steep slopes but, except on recent volcanic features, they are due to erosion guided in some cases by structure. The second distinguishing feature is great elevation. Aside from canyon bottoms, no considerable portion of it is lower than 5,000 feet. Between this and 11,000 feet, there are plateaus of all altitudes. Except where bordered by high mountains on the north and east, the plateau province is higher than sur¬ rounding areas, separated from it by bold escarpments. Another feature which distinguishes the entire province is its remarkable canyons, not one but hundreds. Physiographic differences between the two ecological provinces are based mainly on the degree of wastage. The La Sal province shows a higher or stronger relief from denudation processes; farther south in the Colorado province the plateaus are less deeply and minutely canyoned. Pinyon-j uniper woodlands are found on plateaus, mesas, ridges and lower mountain slopes at elevations from 5,000 to 8,400 feet. Selected scenes from the various provinces are shown in Figures 3.c.l, 3.c.2, and 3.c.3. 3.d . Climate According to a map of the moisture regions of the United States [Thornthwaite , 32 cu •H > cu • in r— I | • (U o 4J X • C d co CO co i — i T— 1 CD CO X S-i o o P w o 00 H & •H P4 *4-4 o £ 0) •H > X c CO • X CM O • O o JS CO i — I CO a) m u P CO 00 t-4 •H *4-1 o £ CU •r4 > TO C CO i — I XI o • o CO • o o • X CO CO c cu o U U pi o 00 o •H Fn *4-1 O •H > 33 1931] , almost the entire pinyon-j uniper distribution falls into the semi-arid classification. However, a wide diversity of climates is found over the five state expanse. Four important factors which exert an influence on local climate are latitude, altitude, moisture sources, and orientation of mountain ranges. Landsberg [1961] discloses how these factors effect climate in the study area. Seasonal weather changes over this region are largely the result of the seasonal migration of two large high-pressure centers: the "Pacific High" and the "Bermuda High." During the wintertime, the Pacific High is in its most southerly position and is relatively weak. This allows storms to swing around its northern edge and cross the west coast sometimes as far south as Lower Cali¬ fornia, During the same period the Bermuda High is weak and far out to sea and has little influence on cold season climate. Thus, winter storms track across Nevada, Utah and Colorado more frequently during October-March than over the two southern states- There is a diminishing effect as the storms pass over the western mountain ranges and high mountains of Utah. Although not as many cold- season storms track across Arizona and New Mexico, those that travel that far south do not have to cross the highest ranges of the Sierras, In the spring the Pacific High strengthens and moves northward, storms become less frequent and tend to move across the country at higher latitudes. Late in the spring and early summer, the Bermuda High develops its westward extension into the Gulf of Mexico and warm, moist, tropical air from that source begins to move from a southeasterly direction across the Southwest. This flow gets weaker as it pushes west and less moisture is transported ini Hid. Western Arizona and southwestern Utah receive considerably smaller amounts of moisture than their eastern sections and the more easterly states of New Mexico and Colo¬ rado. Nevada is too far west to receive significant gulf moisture, so its pre¬ cipitation is very light during the warm season. During September the Pacific High and the Bermuda High begin to weaken. By fall, the Pacific Ocean is again the major storm source. The most striking climatic features of the Escalante-Sevier Province are bright sunshine, widely divergent precipitation pattern between deserts and mountains (because of orientation of mountain ranges to normal storm track) , t dryness and purity of air, and large diurnal temperature ranges. Yearly pre¬ cipitation fluctuations and fluctuations over longer cycles are usually of great magnitude . The mountainous parts of the northern portion receive more precipitation, especially in winter and spring, than the southern mountain portions because they lie within the path most frequented by storms in that half of the year [Alter, 1955]. Monthly distribution of precipitation over most of the province shows June, July and August to be driest. Then there is a gradual increase reaching a maximum in March, April and May. Evaporation is moderately heavy because of the dry atmosphere and high-wind velocities. The most distinctive aspect of the La Sal province climate is the compara¬ tive uniformity of the weather conditions from day to day. This is due to the high mountains which practically surround the section and which deflect the course of low-pressure areas [Sherrier, 1955]. A substantial part of the pre¬ cipitation occurs in winter and early spring; the southern end of the province shows a higher peak at this time of year than the northern portion. There is a prominent tendency toward drought in late spring, and June is often extremely dry. Another important period of precipitation is in late summer during July and August with a tapering-off after October. Skies are generally sunny over the area throughout the year. In the Coronado province precipitation occurs chiefly during two seasons. Maximums are reached during July, August and September (in the form of convec¬ tion showers) and most of the rest is received in December through March. Normally May through June is extremely dry. The percentage of sunshine is very high throughout the year. The extreme western portion of the province is less affected by the flow of Gulf moisture and the summer precipitation peak 35 is not as pronounced. Woodin and Lindsey [1954] divided the pinyon-j uniper type east of the continen¬ tal divide primarily upon the basis of precipitation periods. They were considered more important than temperature as determinants of vegetation differences. Follow¬ ing [Smith, 1940], they used hythergraphs to show differences in the eastern slope subdivisions. Hytherographs for the three ecological provinces delineated in the present study support the divisions chosen (Figure 3.d.l). In the Escalante-Sevier province, the maximum precipitation occurs in late winter and spring leaving the main growing season either dry or dependent upon unreliable short-duration showers. The La Sal province has a good seasonal dis¬ tribution of precipitation and temperature during the growing season. Only May and June show less than an inch of precipitation during spring and summer but mois¬ ture accumulated in the soil from winter and spring storms assists vegetation through this period. Most striking is the Coronado hytherograph which shows the mid-summer peak of precipitation. Vegetation that requires substantial spring moisture cannot be introduced. 3.e Soils There is great variation in soils supporting the woodland communities within each province; local variations occur because of differences in parent materials, topography, microclimate or time for pedogensis. The limited supply of moisture available for plant growth, weathering, and soil leaching is the chief control¬ ling factor in the genesis and the resulting morphology of soils in the pinyon- j uniper type. Low temperatures in the winter and spring, and summer drought further limit soil-forming processes for substantial portions of each year. Soluble salts are usually leached only to depths of 1 to 2 feet. Though parent material differs greatly within short distances, certain genera¬ lizations can be made for the gentle sloping areas sampled in each province. In the Escalante-Sevier province soils are derived from colluvium, alluvium Escalante -Sevier « La Sal c cn T . '1 1 i .50 1.00 1.50 2.00 Mean monthly precipitation in inches " r . __ i " i i .50 1.00 1.50 2.00 Mean monthly precipitation in inches Coronado c 0) S 0 50 1.00 1.50 2.00 2.50 Mean monthly precipitation in inches 3.00 Figure 3.d 1. Mean monthly temperature plotted against average of the normal monthly precipitation for the three ecological provinces. Each point is an average of the monthly figures from several weather stations within one province. 37 and residuum of mainly sedimentary rock. Volcanic rock becomes important also in the southern half of the province. Soil depths seldom exceed 3.5 feet and the entire profile is basic in reaction. Parent materials of the La Sal province are usually residuum, colluvium, and alluvium derived from sandstones and shales. Some igneous intrusive rock was encountered in the vicinity of the Henry and La Sal mountains. In south¬ eastern Utah, loess deposits mantle older landscapes and provide young parent materials [Meiners, 1965]. These were the deepest soils encountered and, in places, exceeded 10 feet. However, usual profile depths never exceeded 3.5 feet. Soil profiles were also basic in nature. Most soils in the Coronado province are developed on residuum, colluvium, and alluvium derived from sandstone, limestone and shale. However, volcanic material caps these sedimentaries in the southeastern portion beginning around Flagstaff, Arizona. Soils under pinyon-j uniper were basic in nature and only occasionally exceeded 4 feet in depth. Directly under the woodland tree canopy organic horizons (01 and 02) occur at the soil surface and vary in thickness according to the age of trees and surface flow of water. Under the new soil classification system [Aandahl, 1965], soils commonly found in the pinyon-j uniper type can be categorized into four Orders: Entisols, Vertisols, Aridisols and Mollisols. Vertisols are common only to the Coronado portion of the present study area, but the other orders are found in all three provinces . Entisols are soils with weakly developed or undeveloped horizons which occur upon materials of recent age or where erosion and sedimentation are highly active; thus very little or no change has been made in the recently deposited parent material . ^ ■'"Under the 1938 soil classification system, these categories would approxi¬ mate the Alluvial, Lithosol, and Regosol great soil groups. 38 The two Suborders found in the pinyon-j uniper woodland type are: Orthents — Skeletal soils formed on a recently deposited alluvium or imperfectly weathered rock fragment, A-horizon 1-18" where present, after which a stony or gravelly, frequently calcareous, platey, or granular structure may occur. No B-horizon. A weak horizon of calcium carbonate enrichment may occur at or near the rock surface. Psamments — Soils consisting of fresh and imperfectly weathered sand or loamy sand. A-horizon 1-8 inches, single grain or granular structure may occur. No B-horizon. C-horizon uniform or stratified materials, soils frequently calcareous, weak carbonate accumulation may be present. Aridisols are soils of the arid region, light colored, low in organic matter, with epipedons (surface diagnostic horizons) generally less than 7 inches thick. Suborders found in the regions studied are as follows: Argids — Those that have argillic horizons, or horizons into which clay has moved. ^ Color is generally brown, but in the La Sal and Coro¬ nado provinces soils of light brown with a reddish cast sometimes occur. The brown surface soil generally grades below into a lighter colored soil and the reddish-brown into a darker red or reddish-brown material (with subsurface material heavier than the surface material) , thence into a layer of carbonate accumulation. The A-horizon is from 2-7 inches thick with structure usually platey in the upper part and granu¬ lar in the lower part and slightly alkaline in reaction. The B-horizon is yellowish-brown to red, about 20 percent more clay, 4-20 inches in thickness, and is moderately prismatic or blocky. Horizons of carbonate enrichment, that are sometimes cemented, occur in or below the B-horizon. Orthids — Typical desert soils having a brownish-gray surface horizon that grades through lighter colored material into a layer of carbonate accumulation and frequently into a hardpan layer. 2 A-horizon is light colored and usually less than 6 inches in depth with a platey structure, and exhibits vesicular porosity in the upper part. B-horizon structure is prismatic, blocky or sub-angular blocky, moderate to strongly alkaline and is usually calcareous (6-14 inches thick). A carbonate layer, usually cemented, occurs in the lower part or below the B-horizon. Mollisols are soils with dark-colored epipedons containing more than 1 percent organic matter and generally are more than 7 inches thick. Mollisols Suborder categorization is based upon climate. Suborder Xerolls and Ustolls would be 1-Brown or Reddish Brown great soil groups would approximate the Argids. ^The Sierozem great soil group would approximate the Orthids encountered. ^The Brown and Reddish Brown great soil groups also approximate several of these great groups. 39 found in the woodland type studied. Mollisols are generally brown at the surface but light browns with a reddish cast may be found in the La Sal and Coronado provinces. A-horizon is 7-20 inches, structure usually platey at the surface and granular in the lower part and slightly alkaline in reaction. B-horizon, where present, is lighter in color except where reddish brown at the surface. Reddish-browns grade into a darker red or reddish-brown material heavier than the surface horizon. The B-horizon may contain 20 percent more clay than the A-horizon. It is 4-20 inches deep, moderately prismatic or blocky. A carbonate enrichment horizon that is sometimes cemented occurs in or below the B-horizon. Great groups encountered of the Suborder Xerolls (soils seasonably dry when not frozen) are Argixerolls (soils with an argillic horizon) and Haploxerolls (soils with a less altered B-horizon or a C-horizon below a mollic epipedon) . In the Suborder Ustolls (dry climates, usually hot in the summer) great groups encountered are Argustolls, soils with an argillic horizon; Calcustolls, soils with a calcic horizon but on Argillic horizon and Haplustolls, soils with a mollic epipedon on a C-horizon or less altered horizon. Vertisols are soils formed on basalt lava and basalt cinders that cap sedimen¬ tary rocks.'*' The Suborder, Usterts, contains Vertisols associated with dry cli¬ mate and hot summers. Usterts — Dark colored A-horizon that varies in thickness (20 to 50 inches). The surface 1 to 4 inches has strong granular structure, but below this the horizon may have prismatic or weak to strong blocky struc¬ ture with a slightly alkaline reaction. There is no B-horizon. C-hori¬ zon is massive with a large lenticular pattern of cracks when dry. Wide vertical cracks commonly extend from the soil surface into the C-horizon. These are 1 to 25 cm (1/2 to 10 inches) wide for at least half the depth of the solum. These soils are dominated by montmorillonite clay (over 35% clay) . In table 3.e. 1 the many soils sampled during the course of the present study have classified according to the above system. ^This category approximates the grumusols of the older classification systems 40 Table 3.e.l. Percent of soil observations as classified in the new soil classi¬ fication system Ent isols Aridisols Molli- Verti- No . of Province Ortherts Psamments Argids Orthids sols sols i observa¬ tions 24% 2% 24% 31% 19% 0 119 Escalante-Sevier 28% 9% 41% 8% 14% 0 139 La Sal 27% 3% 46% 8% 10% 6% 124 Coronado When the total observations are summed, it is observed that the quantity falling in each order is about the same in every province. Thus, for the purposes of this report, it is concluded that soils provide the weakest element in demarcating pinyon-j uniper ecological provinces. 3.f. Vegetation'*' Sampling was restricted to areas supporting Pinus edulis , P inus monophylla , Juniperus os teosperma , or Juniperus monosperma ; however, Juniperus scopulorm and Juniperus deppeana were minor species in some communities. Where Gambel oak (Quercus gambelii) was encountered, it was never of sufficient height to be part of the tree canopy so it was considered an understory species. Pinyon-j uniper woodlands of the Escalante-Sevier province have a more uni¬ form composition that those of the La Sal or Coronado provinces (Table 3.f.l). Utah juniper (Juniperus osteosperma) is the only juniper encountered at all ele¬ vations sampled. However, single leaf pinyon (Pinus monophylla) extends spora¬ dically throughout the province. In the southeast portion of the province, Colorado pinyon (Pinus edulis) may dominate or be a minor species of woodland communities; where these two pine species interfuse, individual trees may have -^-Nomenclature for trees, shrubs and forbs follows Harrington [1964]; nomen¬ clature for grass follows Hitchcock [1950]. 41 both single and double leaves. In the restricted sampling area, the upper elevational range of the trees in this province was never visited. Data were collected on benchlands and low rolling hills. These areas grade sharply into steep hillsides also vegetated by pinyon and juniper trees. Since sampling was confined to the lower slopes, the elevation range was generally between 5,500 and 7,000 feet. The lower woodland boundary usually grades into a sagebrush-grass type. Important understory species vary with both elevation and latitude. Common plants found throughout the province are big sagebrush (Artemisia t ridentat a) , black sagebrush (Artemisia tridentata nova) , and chicken sage (Artemisia triden- tata arbuscula) . The latter two species occur on ridges and slopes whereas big sage grows on deeper soils. Small rabbit brush (Chrysothamnus viscidif lorus) , bitter brush (Purshia tridentata) , squirreltail (Sitanion hystrix) , Sandberg bluegrass (Poa secunda) , bluebunch wheatgrass (Agropyron spicatum) , Indian rice- grass (Oryzopsis hymenoides) , Nevada bluegrass (Poa nevadensis) , needle and thread grass (Stipa comata) , white borage (Cryptantha spp.) and Phlox spp. are other common understory species. Table 3.f.l shows how certain species are related to latitudinal changes. Sites were grouped into three sub-provinces. Of the species found in the south sub-province, galleta grass (Hilaria jamesii) and buckbrush (Ceanothus greggii) are probably the only species not found in northern latitudes. Cliff rose (Cowania s t ansburiana) appears to be important only in the south half of the Escalante-Sevier province. Several of the plants relegated to the central sub-province are species that join the general woodland community listed above at higher elevations; the specific elevation would change as the latitudinal location changes. They are serviceberry (Amelanchier alnif olia) , snowberry (Symphoricarpos longif lorus) , mountain mahogany (Cercocarpus ledif olius) , and Idaho fescue (Festuca idahoensis) . 42 All of these species except mountain mahogany were probably more widely distri¬ buted before the lands become subject to heavy livestock and game concentrations. Mountain mahogany is generally found at higher elevations than the pinyon- juniper belt in the southern sub-unit. « Species that appear to be more common in the north sub-unit are balsam root (Balsamorhiza sagitata) , Phlox longifolia and larkspur (Delphium spp.). Woodland stands of the La Sal province are dominated by Colorado pinyon (Pinus edulis) and Utah juniper (Juniperus osteosperma) . Single leaf pinyon (Pinus monophylla) has been reported in the area [Daubenmire, 1943]; however, it happened that none was encountered during the course of the present study. Rocky Mountain juniper (Juniperus scopulorum) may be a minor species at the upper elevational range. More often the pinyon-j uniper belt grades into a mountain brush type at the upper elevational limits but may grade into a ponderosa pine (Pinus ponderosa) or Douglas fir (Pseudotsuga menziesii) type. Several of the species universally found in the Escalante-Sevier province play the same role in this province. They are big sagebrush, chicken sage, little rabbitbrush, bitter brush, Indian ricegrass, Squirreltail and white borage. Additional species that characterize the province are mutton grass (Poa f endleriana) , blue grama grass (Bouteloua gracilis) , dry land carex (Carex spp.) and snake weed (Gutierrezia sarothrae) . Beginning at medial elevations and extending to the upper range in the woodland belt, birchleaf mahogany (Cercocarpus montanus) , serviceberry (Arne 1 an chi er alnif ol ia) , gambel oak (Quercus gambelii) , June grass (Koeleria cristata) , and goldenrod (Solidago spp.) become important species also. Table 3.f.2 indicates how species are restricted in lat itudinally divided sub-provinces. For example, galleta grass (Hilaria j ame s s i i ) is common to more southern latitudes in both the Escalante- Sevier and the La Sal provinces. Three awned grass (Aristida spp.) is also more common in the south and central portion of the La Sal province at 43 low elevations. Arizona fescue (Festuca arizonica) is found occasionally at mid and high elevations. Several species, notably western wheatgrass (Agropyron smithii) , Sandberg bluegrass (Poa secunda) , Phlox spp . and Aste£ spp. were more often found in central and north sub-provinces. Also in the central and north sub provinces better sites (higher elevations) were found bluebunch wheatgrass (Agropyron snicatum) , beardless wheatgrass (Agropyroji inerme) and snowberry (Svmphoricarpos spp . ) . In the Coronado province, Colorado pinyon (Pinus edulis) and Utah juniper (Juniperus osteosperma) are the main dominants. Single leaf pinyon (Pinus mono - phvlla) occurs with Colorado pinyon in northwestern Arizona but is usually a minor species. In the southeastern portion of the province, one seeded juniper (juniperus monosperma) may be present with Pinus edulis or may grow in pure stands. Rocky Mountain juniper (Juniperus scopulorum) may be present in small quantities throughout the province on favorable sites. The lower woodland ecotone consis¬ tently grades into a grass type while the upper ecotone grades into ponderosa pine (Pinus ponderosa). This province produces the largest trees of both pinyon and juniper. This is probably due to the distribution of precipitation, for the greatest portion falls during the growing season (Figure 3.d.l). Colorado pinyon trees 40-45 feet tall were measured on sites east of Farmington, New Mexico, and in Arizona. Juniper trees also grew to 35 feet on some of the best sites. The tallest pinyons (47 feet) were recorded on the south rim of the Grand Canyon where timber and woodland communities converge. In this province, the understory is dominated by grass. Blue grama is most common and at many sites accounted for 40 or more percent of the understory /Tulo q f 3') Other important grasses are squirreltail (Sit anion composition UaDie r Wstrix), three awned grass (Aristida spp.), galleta grass (Hilaria j amesii) , black grama (Bouteloua eriopoda) , Indian ricegrass (Oryzopsis hymenoides) , side oats grama (Bouteloua n.rtipendula) and on somewhat more mesic sites mutton grass 44 low elevations. Arizona fescue (Festuca arizonica) is found occasionally at mid and high elevations. Several species, notably western wheatgrass (Agropyron smithii) , Sandberg bluegrass (Poa secunda) , Phlox spp . and Aster spp. were more often found in the central and north sub-provinces. Also in the central and north sub-provinces on better sites (higher elevations) were found bluebunch wheatgrass (Agropyron spicatum) , beardless wheatgrass (Agropyron inerme) and snowberry (Symphoricarpos spp . ) . In the Coronado province, Colorado pinyon (Pinus edulis) and Utah juniper (Juniperus osteosperma) are the main dominants. Single leaf pinyon (Pinus mono- phylla) occurs with Colorado pinyon in northwestern Arizona but is usually a minor species. In the southeastern portion of the province, one seeded juniper (Juniperus monosperma) may be present with Pinus edulis or may grow in pure stands. Rocky Mountain juniper (Juniperus scopulorum) may be present in small quantities throughout the province on favorable sites. The lower woodland ecotone consis¬ tently grades into a grass type while the upper ecotone grades into ponderosa pine (Pinus ponderosa) . This province produces the largest trees of both pinyon and juniper. This is probably due to the distribution of precipitation, for the greatest portion falls during the growing season (Figure 3.d.l). Colorado pinyon trees 40-45 feet tall were measured on sites east of Farmington, New Mexico, and in Arizona. Juniper trees also grew to 35 feet on some of the best sites. The tallest pinyons (47 feet) were recorded on the south rim of the Grand Canyon where timber and woodland communities converge. In this province, the understory is dominated by grass. Blue grama is most common and at many sites accounted for 40 or more percent of the understory composition (Table 3.f.3). Other important grasses are squirreltail (Sitanion hystrix) , three awned grass (Aristida spp.), galleta grass (Hilaria jamesii) « black grama (Bouteloua eriopoda) , Indian ricegrass (Oryzopsis hymenoides) , side oats grama (Bouteloua curt ipendula) and on somewhat more mesic sites mutton grass 44 45 Table Average composition percentage and consistency of woodland tree species and understory species of the Escalante-Sevier province. 3.f.i Note how certain understory species are found primarily in the latitudinal sub-province divisions. South sub-province | Central sub -province 1 North sub-province Stand number 279 280 270 80 140 93 87 259 171 178 181 104 103 211 358 212 350 97 94B 251 183 187 95 248 191 186 101 250 100 98 190 184 189 Species ■X. Abundance classification Juniperus osteosperma 100 61 100 91 100 47 100 100 85 100 100 55 Pinus monophylla P 39 9 53 100 15 P 45 Pinus edulis P P Sitanion hystrix 10 2 3 7 5 2 4 18 13 10 5 5 Oryzopsis hymenoides 2 1 20 15 5 12 1 8 15 14 10 10 Poa secunda 1 3 3 2 2 3 6 5 Agropyron spicatum 9 1 6 5 5 5 17 10 Phlox spp. 5 3 2 5 1 3 5 Artemisia tridentata 35 1 5 28 5 42 5 35 3 Chrysothamnus viscidi florus 8 1 8 10 15 23 7 Poa nevadensis 5 2 2 2 1 Purshia tridentata 12 67 3 20 6 2 10 12 Artemisia tridentata nova 61 48 15 47 50 Cryptantha spp. 1 1 P 12 1 5 1 2 Stipa comata 3 2 2 1 1 2 Eriogonum spp. 23 1 1 2 1 100 3 10 53 47 42 58 1 5 22 78 88 12 2 3 2 15 58 2 35 18 18 7 P 7 20 68 19 28 7 2 30 73 2 1 75 25 5 13 10 50 5 1 57 43 5 2 100 100 55 2 10 33 P 4 2 2 18 40 100 P 5 11 10 30 2 10 100 100 100 50 50 1 4 47 53 5 5 61 39 1 2 100 P 1 1 93 7 100 15 2 3 2 15 5 5 15 28 7 13 10 10 60 65 P 27 2 5 20 7 15 P 30 5 10 55 P 1 10 30 5 10 2 12 5 5 20 10 5 8 40 53 10 2 Astragalus spp. Opuntia spp. Artemisia tridentata arbuscula Lupinus spp. Sphaeralcea spp. Atriplex canescens Koeleria cristata Ceanothus greggii Hilaria jamesii Agropyron subsecundum Vicia spp. Symphoricarpos longiflorus Cowania stansburiana Cercocarpus ledifolius Ephedra spp. Amelanchier alnifolia Stipa thurberiana Agoseris spp. Aster spp. Festuca idahoensis Grayia spp. Ribes spp. Eurotia lanata Cirsium spp. Senicio serra Castilleia spp. Balsamorhiza sagitata Cryptantha flava Stipa columbiana Euphorbia spp. Senicio uintahensis Elymus condensatus Agropyron smithii Phlox longifolia Delphinum spp. Tetradyma canescens 15 6 64 P 66 15 c c 2 4-10 ■'"* c "H -U 4-1 CU4-I CO 1 O t4 0 3 (J OJ O 44 o O 44 4-1 (X (X o « B px c IX O O U o 62 38 75 ?8.5 97 2.1 64 6 4.1 82 5.5 82 9.4 73 LI. 9 70 4.5 67 .0.3 55 5.6 55 4. 1 52 5.7 39 .4.0 36 .8 30 .5 27 1.3 18 .4 15 .3 12 4.4 9 P 9 .3 9 .8 6 .3 9 .5 3 .2 3 .2 6 . 1 3 2.0 15 .7 9 .5 9 .3 9 .4 6 . 1 6 . 1 6 . 1 6 .1 . 1 3 .1 3 . 1 3 .03 3 .03 3 .03 3 .5 12 .3 12 .1 12 .3 9 .3 9 .1 9 .1 9 . 1 6 . 1 6 .1 3 47 Table Average composition percentage and consistency o 3. f. 2 Species Drth sub- -province X percent composition Percent construction Stand number 169 300 45 48 338 L97 247 319 320 146 323 195 192 43 325 246 322 324 145 245 Juniperus osteosperma 18 18 75 19 8 1! 25 23 100 100 19 11 41 35 21 25 27 12 11 88 29 37.5 98 Pinus edulis 82 82 25 81 92 8: 75 77 81 . 89 59 65 79 75 73 88 89 12 61 62.4 93 Juniperus scopulorum 2 Oryzopsis hymenoides 3 15 P 30 3 20 20 10 3 5 10 10 10 10 8 25 8.1 72 Poa fendleriana 5 1 3 16 5 4< 10 2 20 30 13.0 69 Sitanian hystrix 5 8 2 2 8 28 10 2 5 5 10 P 5 5.5 59 Opuntia spp. 1 4 5 2 1 5 5 10 3.3 52 Artemisia tridentata 7 2 20 10 15 4 10 5 28 10 6.4 41 Bouteloua gracilis 34 5 25 10 2 5 13 5 40 5 4.6 39 Carex spp. 3 3 5 1C 5 3 15 5 25 5 14 10 2.6 39 Cercocar pus montanus 10 c 2 45 20 15 35 5.4 36 Cryptantha spp. 1 3 4 1 2 3 4 P 3 . 9 34 Amelanchier alnifolia 5 1 P 4 15 P 15 3.1 33 Gutierrezia sarothrae 15 P 5 3 3 1 s 26 Purshia tridentata 5 25 15 10 1.6 26 Solidago spp. 20 5 25 10 35 3.6 26 Koeleria cristata 15 5 5 20 27 1 9 25 Artemisia tridentata arbuscula 10 10 10 ? S 23 Quercus gambelii 40 2 2.7 20 Gilia spp. P P 5 1 3 .3 20 Artemisia tridentata nova 7 10 2 5 5 1 0 16 Chrysothamnus viscidif lorus 5 1 5 1.0 16 Eriogonum spp. 2 1 P ,i 16 Penstemon spp. 2 5 5 2 1 .6 16 Astragalus spp. 2 .6 10 Artemisia frigida 1 . 1 5 Cryptantha flava 1 5 .2 5 Stipa columbiana .2 3 Yucca spp. 5 P . 1 9 Festuca arizonica 10 32 2 3 .9 9 Hilaria jamesii 2 0 8 Chrysothamnus spp. 3 .2 7 Aristida longiseta . 9 7 Senicio uintahensis .3 7 Erigeron spp. 2 .i 7 Lupinus spp. 1 2 .i 11 Sporobolus cryptandrus 2 .i 5 Vicia spp. 1 2 ,i 5 Artemisia ludoviciana 2 .03 2 Agropyron spicatum .1 5 Ephedra spp. .03 3 Arctostaphylos spp .03 2 Chrysopsis villosa .6 2 Festuca spp. .03 2 Castilleja spp. Agropyron smithii 8 35 40 12 5 10 12 40 40 4.6 36 Phlox spp. 10 20 5 3 2 20 5 10 5 5 2.2 30 Stipa comata 1 17 5 5 25 1.9 21 Symphoricarpus spp. 5 5 .8 14 Hymenoxys argentea 5 1.2 9 Poa spp. 5 .9 8 Phlox longifolia 7 .3 6 Aster spp. . i 6 Sphaeralcea spp. P 3 2 .1 6 Balsamorhiza sagitata P .1 6 Bahia dissecta a 5 Senicio spp. P p 5 Chrysothamnus nauseosus ,i 3 Eriogonum spp. (shrub) ,i 3 Peraphyllum ramosissimum .2 3 5 ,i 3 Agropyron inerme 30 3 35 20 10 8 10 5 4.6 24 Poa secunda 2 2 8 . 6 18 Penstemon spp. (shrub) 3 5 .4 8 Haplopappus gracilis 12 .4 5 Eurotia lanata P 2 .03 3 47 comPos * n percentage and consistency of woodland tree species and understory species of the La Sal province. Ntote how certain understory species are found primarily in the latitudinal sub-province divisions. 3. f. 2 Species South sub-province Central sub-province North sub-province Stand number 169 300 45 48 338 4 393 166 47 336 36 37 46 51 167 406 332 5 347 Juniperus osteosperma Pinus edulis Juniperus scopulorum Oryzopsis hymenoides Poa fendleriana Sitanian hystrix Opuntia spp. Artemisia tridentata Bouteloua gracilis Carex spp. Cercocar pus montanus Cryptantha spp. Amelanchier alnifolia Gutierrezia sarothrae Purshia tridentata Solidago spp. ■ Koeleria cristata Artemisia tridentata arbuscula Quercus gambelii Gilia spp. Artemisia tridentata nova Chrysothamnus viscidif lorus Eriogonum spp. Penstemon spp. Astragalus spp. 18 82 3 5 5 1 7 34 3 1 15 18 82 15 1 10 3 5 P 5 20 15 75 25 19 81 P 16 25 15 5 10 5 40 10 8 92 30 5 25 15 85 40 10 33 67 30 P 10 35 65 2 3 56 20 71 29 68 56 38 7 38 84 17 21 44 65 44 62 93 62 16 83 79 100 56 35 15 10 10 25 4 10 35 10 45 77 17 50 25 2 43 32 5 10 15 5 25 2 15 5 5 5 5 P 5 65 56 5 5 35 T 2 8 8 20 10 30 1 5 1 P 10 P 10 2 5 3 2 P 45 10 1 1 2 t 40 P 2 1 P 1 1 15 P 17 83 32 P 349 7 150 342 349B 151 161 348 296 157 340 346 41 164 163 160 148 193 147 149 143 196 194 42 144 321 197 247 319 320 146 323 195 192 43 325 246 322 324 145 245 C -u 0) *H o 05 u o CL. 6 Abundance classif icat ion o ■ X o 54 30 16 31 31 13 57 18 32 22 ii 42 51 50 62 13 22 11 23 43 100 70 38 40 100 65 25 23 100 100 19 11 41 35 21 25 27 12 11 88 29 37.5 46 70 84 69 69 87 43 82 68 78 89 58 49 50 38 87 78 89 77 57 30 62 60 35 75 77 81 89 59 65 79 75 73 88 89 12 61 62.4 38 10 1 36 2 9 5 20 10 30 5 5 15 10 5 1 2 3 24 8 3 20 20 10 3 5 10 10 10 10 8 25 8.1 10 6 5 20 43 9 30 25 8 3 30 5 10 10 5 14 3 19 19 12 2 10 2 20 30 13.0 3 1 5 5 5 2 40 7 20 25 5 5 5 3 28 10 2 5 5 10 P 5 5.5 2 3 5 2 5 25 10 P P 7 12 15 1 2 2 2 3 5 2 1 5 5 10 3.3 10 20 20 28 10 2 29 10 20 10 15 4 10 5 28 10 6.4 3 2 5 5 20 25 10 2 7 25 10 2 5 13 5 40 5 4.6 2 P P 5 3 11 5 10 3 10 5 3 15 5 25 5 14 10 2.6 10 P 10 10 2 10 43 10 15 5 10 2 P 5 2 2 30 5 10 40 P 5 2 25 20 2 10 15 12 10 10 73 2 20 10 23 15 15 18 10 P 45 3 4 20 15 10 20 10 1 27 10 15 15 35 35 3 10 30 5.4 .9 3.1 1.5 1.6 3.6 1.9 2.5 2.7 .3 1.0 1.0 .1 .6 .6 98 93 2 72 69 59 52 41 39 39 36 34 33 26 26 26 25 23 20 20 16 16 16 16 10 Artemisia frigida Cryptantha flava Stipa columbiana Yucca spp. Festuca arizonica Hilaria jamesii Chrysothamnus spp. Aristida longiseta Senicio uintahensis Erigeron spp. Lupinus spp. Sporobolus cryptandrus Vicia spp. Artemisia ludoviciana Agropyron spicatum Ephedra spp. Arctostaphylos spp. Chrysopsis villosa Festuca spp. Castilleja spp. Agropyron smithii Phlox spp. Stipa comata Symphoricarpus spp. Hymenoxys argentea Poa spp. Phlox longifolia Aster spp. Sphaeralcea spp. Balsamorhiza sagitata Bahia dissecta Senicio spp. Chrysothamnus nauseosus Eriogonum spp. (shrub) Peraphyllum ramosissimum Psoralea spp. Agropyron inerme Poa secunda Penstemon spp. (shrub) Haplopappus gracilis Eurotia lanata 10 .1 .2 .2 .1 .9 2.0 .2 .9 .3 .1 .1 .1 . 1 .03 . 1 4.6 2.2 1.9 .8 1.2 .9 .3 .1 .1 .1 .1 .1 .1 ? 11 5 5 2 5 .03 3 .03 2 .6 2 .03 2 P 2 36 30 21 14 9 5 5 3 3 3 .1 3 4.6 24 .6 18 .4 8 .4 .03 construction Table 3. f. 3 Average composition percentage and consistency of woodland 49 Species Juniperus osteosperma Pinus edulis Juniperus monosperma Pinus monophylla Juniperus depeana Juniperus scopularum Bouteloua gracilis Gutierrezla sarothrae Sitanian hystrix Opuntia spp. Aristida spp. Hilaria jamesii Foa fendleriana Oryzopsis hymenoides Yucca spp. Sphaeralcea spp. Bouteloua curtipendula Artemisia tridentata Penstemon spp. (shrub) Ephedra spp. Sphaeralcea spp. Stipa comata Koeleria cristata Astragalus spp. Bouteloua eriopoda Quercus gambelii Erigeron spp. Foa spp. Senicio spp. Amelanchier spp. Solidago spp. Cowania stansburiana Berberis fremontii Quercus turbinella Euphurbia Atriplex canescens Phlox spp. Cryptantha spp. Eurotia lanata Artemisia tridentata nova Lycium spp. Stipa spp. Muhlenbergia rigens Solanum spp. Coleogyne romosissima Ceanothus greggi Stipa columbiana Penstemon pachyphyllus Hymenoxys richardsonii Rhus trilobata Blepharoneuron tricholepis Lupinus brevicaulis Penstemon eatoni Ribes spp. Sporobolus wrightii Muhlenbergia wrightii Menodora scabra Eriogonum spp. Chrysothamnus spp. Poa pratensis Cercocarpus montanus Artemisia frigida Aster spp. Festuea arizonica Arctostaphylos patula Castilleja spp. Muhlenbergia torreyi Purshia tridentata Carex spp. Lupinus spp. Agropyron smithii Muhlenbergia pungens Lycurus phleoides Penstemon linarioides Chrysothamnus viscidif lorus Nolina spp. Cercocarpus breviflorus Symphoricarpus spp. Tetradyraa spp. Agropyron inerma st sub -province a o 4J v4 C U 4) -H O m a o 4J 4-1 c o S. 0 p!J d X 8 8 66 100 Bouteloua gracilis 3 20 2 50 19 10 33 20 50 50 5 51 33 5 17 50 68 80 53 40 45 62 50 10 58 52 79 18 62 86 45 35 80 33 69 84 56 72 1 50 15 20 59 2 15 Gutierrezia sarothrae 39 15 30 30 7 40 2 P 21 20 1 5 13 16 13 10 10 3 5 2 2 5 14 10 10 10 10 3 3 49 3 30 8 15 5 15 15 10 1 18 10 2 3 10 5 Sitanian hystrix 1 1 P 5 3 3 3 2 5 3 1 2 3 10 2 3 5 3 P 1 5 3 10 2 1 5 2 2 1 10 P 25 10 8 3 20 Opuntia spp. 1 1 P P 2 4 1 3 1 10 P 1 P 1 2 P 1 P 1 1 1 3 2 5 P 1 4 P Aristida spp. 5 3 10 1 20 5 2 1 1 10 P 1 2 2 2 3 Hilaria jamesii 18 4 5 3 15 18 70 5 4 1 6 20 23 3 Foa fendleriana 4 10 P 12 P 8 5 5 14 5 2 5 2 1 3 5 2 3 2 5 5 3 5 Oryzopsis hymenoides 10 2 10 3 5 3 4 1 4 1 1 P 3 2 P 10 5 5 20 9 5 Yucca spp. 1 15 1 4 10 1 P 1 3 3 3 P P .P P Sphaeralcea spp. 2 1 2 3 1 3 2 2 P 3 2 2 1 2 1 2 1 3 Bouteloua curtipendula 1 5 2 3 20 5 5 3 P 1 5 3 20 8 10 Artemisia tridentata 5 10 10 30 40 60 14 7 15 5 7 52 10 10 Penstemon spp. (shrub) 2 1 5 1 1 2 2 30 1 2 2 5 5 5 2 P 2 Ephedra spp. 1 2 P 2 1 1 2 2 5 1 10 Sphaeralcea spp. 3 50 P Stipa comat a 5 15 17 P P 2 5 Koeleria cristata 5 20 5 3 2 2 5 10 Astragalus spp. 5 1 1 20 1 3 1 1 18 18 45 14 60 1 30 10 2 70 8 30 3 10 25 2 P 25 10 40 25 2 3 10 35 10 20 20 82 2 55 10 23 48 15 62 10 10 72 5 10P 68 8 48 5 89 2 P P 82 5 20 93 33 100 22 43.8 87 7 67 78 37.0 76 53 9.3 13 1.7 8 47 3.0 6 0.3 3 5 75 55 72 65 42.2 93 33 2 2 5 10 9.8 90 15 1 3.5 62 2 1 P 1.1 56 5 1.5 38 44 2 1 15 4.6 37 1.5 32 1.5 32 .7 30 .6 30 5 1.4 28 3 33 4.8 25 1.0 25 .5 17 5 1.1 15 .7 13 .7 11 .5 11 .8 11 1.1 11 1 .1 10 5 2 .3 8 .03 4 .04 4 Solidago spp. Cowania stansburiana Berberis fremontii Quercus turbinella Euphurbia Atriplex canescens Phlox spp. Cryptantha spp. Eurotia lanata Artemisia tridentata nova Lycium spp. Stipa spp. Muhlenbergia rigens Solanum spp. Coleogyne romosissima Ceanothus greggi Stipa columbiana Penstemon pachyphyllus Hymenoxys richardsonii Rhus trilobata Blepharoneuron tricholepis Lupinus brevicaulis Penstemon eatoni Ribes spp. Sporobolus wrightii Muhlenbergia wrightii Menodora scabra Eriogonum spp. Chrysothamnus spp. Foa pratensis Cercocarpus montanus Artemisia frigida Aster spp. Festuea arizonica Arctostaphylos patula Castille ja spp. Muhlenbergia torreyi Purshia tridentata Carex spp. Lupinus spp. Agropyron smithii Muhlenbergia pungens Lycurus phleoides Penstemon linarioides Chrysothamnus viscidif lorus Nolina spp. Cercocarpus breviflorus Symphoricarpus spp. Tetradyma spp. Agropyron inerma Gilia spp. Rhamnus crocea (Poa fendleriana) is found. Common shrubs and forbs are big sagebrush Artemisia tridentata) , Yucca spp. , snake weed (Gutierrezia sarothrae) . globe mallow (SEhaealcea spp.) and at the upper elevational extremes, gambel oak (Quercus gambelii) . Unlike the other two provinces, the vegetational changes occur longitudi¬ nally instead of latitudmally . Preponderance of summer precipitation decreases as one travels westward, which may account for the different species in the sub-provinces (Table 3.e.3). Of the plants that are concentrated on the west and central sub-provinces, these appear to be the most important: cliffrose (Cowania standsburianal . Algerita (Berberis fremontii) , live oak (Quercus turbinella) and Phlox spp. Ring grass (Muhlenbergia torreyU , wolf tail (Lycuras phleoides) . bitter brush (Purshia .tridentata and birch leaf mahogany (Cercocarpus montanus) mainly occur m the central and east sub-provinces. At higher elevations, squawbrush (Rhus trilobata) , rubber plant (Hymenoxys richardsonii) . pine dropseed (Blepharoneurnn tricholepis) , Arizona fescue (Festuca arizonica) , Kentucky bluegrass (Poa parten- s_is_) , and manzanita (Artos taphylus patula) occur. This study indicates distribution of precipitation as probably being the most important single factor in the division of provinces. And when coupled with temperature influences, precipitation accounts for the general vegetation compo- sition changes throughout the study area. Assuming present range conditions, woodland sites in the Coronado province generally out-produce similar sites in the other two provinces in both under¬ story production and individual tree production. However, woodlands seeded to introduced grass species are far more productive in the Escalante-Sevier and La Sal Provinces. Seasonal precipitation distribution does not favor seeding grass species in the Coronado province. The climatic pattern and local soil conditions within the latter province may discourage any seeding practice. Response of the understory native species to land treatment appears to be 51 different also. Bunchgrass understory increases production following tree removal treatments through a gain in vigor (of the existing plants) and through additional production from new plants. Following tree removal, shortgrass species appear to gain (in vigor only) for several years. Increases in ground cover seem to require a long time for materialization. Generalizations for the woodland type may be made only within certain limits. Great caution is needed, however, when transferring a management practice common to one area to another. The proposed province alignment provides a basis for comparing management potentials for pinyon- juniper woodlands throughout the study area. 52 REFERENCES (1) Aandahl, A. R. 1965. The first comprehensive soil classification system. Journal of Soil and Water Conservation 20:243-246. (2) Alter, 1933. Western Utah, Climatic Summary of the United States from establishment of stations to 1930, Section 20, U. S. Department of Agriculture Weather Bureau, 40 p. (3) Daubenmire, R. F. 1943. Vegetational zonation in the Rocky Mountains. Botanical Review 9:325-393. (4) Franklin, J. P. 1965. Tentative ecological provinces within the true fir- hemlock forest areas of the Pacific Northwest. U. S. Forest Service Pacific Northwest Forest and Range Experiment Station Research Paper PNW 22, 31 p. (5) Fenneman, N. M. 1931. Physiography of Western United States. McGraw-Hill Book Company, Inc., New York, 534 p. (6) Harrington, H. D. 1964. Manual of the Plants of Colorado, Sage Books. Denver, Colorado, 2nd edition, 666 p. (7) Hitchcock, A. S. 1950. Manual of the Grasses of the United States, U.S.D.A. Miscellaneous Publication No. 200, 1051 p. (8) Hunt, Charles B. 1956. Cenozoic Geology of the Colorado Plateau. Geolo¬ gical Survey Professional Paper 279, 99 p. (9) Landsberg, H. E. 1961. Weather, a factor in plant location. U. S. Depart¬ ment of Commerce, Weather Bureau, 23 p. (10) Little, E. L. 1950. Southwestern trees; A guide to the native species of New Mexico and Arizona. U.S.D.A. Agriculture Handbook No. 9, 109 p. (11) Meiners, W. R. 1965. Some geologic and edaphic characteristics useful to management programming within the pinyon- juniper type. Unpublished thesis, Utah State University Library, 68 p. (12) Merkle, J. 1952. An analysis of a pinyon-j uniper community at Grand Canyon. Ecology 33:375-384. (13) Noland, T. B. 1943. The Basin and Range Province in Utah, Nevada, and California. U. S. Geological Professional Paper 197-D, 196 p. (14) Pearson, G. A. 1931. Forest types in the southwest as determined by cli¬ mate and soil. U.S.D.A. Technical. Bulletin No. 247, 143 p. (15) Phillips, F. J. 1909. A study of Pinyon Pine. Botanical Gazette 48:216-223. (16) Richmond, G. M. 1962. Quartenary stratigraphy of the La Sal Mountains Utah. Geological Survey Professional Paper 324, 135 p. (17) Sherrier, 1933. Western Colorado, climatic summary of the United States — From establishment of stations to 1930. Section 22 U. S. Department of Agriculture Weather Bureau, 32 p. 53 (18) Smith, A. D. 1940. A discussion of the application of a climatological diagram, the hythergraph, to the distribution of natural vegetation types. Ecology 21:184-191. (19) Stoddart, L. A. and A. D. Smith. 1955, Range Management . McGraw-Hill Book Company, Inc., New York. 433 p. (20) Thornthwaite , C. W. 1931. The climate of North America according to a new classification. Geographical Review 21:633-655. (21) Woodbury, Angus M. 1947. Distribution of pigmy Conifers in Utah and northeastern Arizona. Ecology 28:113-126. (22) Wooden, H. E. and A. A. Lindsey. 1954. Juniper-pinyon east of the conti¬ nental Divide as analyzed by the line strip method. Ecology 35:473-489. 54 4. SITE CLASSIFICATION OF THE PINY ON- JUNIPER WOODLANDS Site quality is measured by the productivity of the land when it is used at full capacity. Productivity at full capacity is a function of the many site factors which influence growth. Forest stand conditions are rare which will permit a direct estimate of site quality by means of measuring the actual crop produced by the site. Yield tables for particular species have been constructed by searching for stands which appear to be fully stocked for their age but they are only applicable to pure, even-aged stands. A yield table provides a means of estimating how fully stocked a particular stand may be only if the site qual¬ ity is already known. Because volume production is subject to variation from changes in density, height growth has gradually attained acceptance as the most independent measure of the quality of a site. Though height growth is affected adversely by low density stocking and young trees have frequently shown a higher growth rate than the site can maintain to maturity, in general, the height to which a tree will grow at a particular age is used as an index of site quality. The height-age relationship is unsatisfactory for use in uneven-aged stands as a 50 year old tree may be 3 feet or 50 feet tall, depending upon whether it was suppressed by an overstory or free to grow without overhead competition. An alternative measure has been suggested and developed for red spruce by McLintock and Bickford [1957]: the height attained when a tree reached a par¬ ticular diameter. Stands in the pinyon-j uniper type are not even-aged, are composed of varying proportions of pinyon and juniper, and rarely approach what could be called full¬ stocking. In fact, most stands are moderately open and become increasingly so on the poorer sites. The uneven-aged character of the stands precludes the use of the height- age relationship for developing a site index for classifying 55 site qualities. By contrast, the height-diameter relationship provides a sound basis for pinyon-j uniper site classification. 4. a. Pinyon Site Index Curves — T. W. Daniel After the first field season, the heights over diameters-at-one-f oot for trees selected on or around each plot, which were judged as having typical forms for the height-diameter curve, were plotted by species. The curve was drawn by ocular estimate. Where a reasonable number of "curve trees" had been available at a plot, there was usually a clear-cut best fit especially between 6 to 14 inches in dia¬ meter. Below 6 inches and sometimes above, the trees on some plots were fre¬ quently either taller or shorter than expected for their diameters. It was often the case that the too tall tree was quite old for its diameter. The same tree, when plotted on the height-age or diameter-age curves, was shorter and smaller in diameter than expected for its age. The abnormality is attributed to suppression as such a tree usually showed evidence of having come up through competition. Another exception was the occasional fine-branched, thin-crowned, even short-crowned tree that would be quite tall and slender when obviously open grown. The shore tree for its diameter was a broad bushy type and young for its diameter. Above 14 inches in diameter, the form of the tree had a significant influence on its height-diameter relationship. As has been indicated, the "site tree" was picked for its maturity and the tallest mature or overmature was selected where a choice was available. A tree that maintained a single main stem through¬ out its life maintained a growth rate comparable to the younger tree (Figure 4,a,l). The closer to the ground that the main stem lost its dominance and the more the upper crown branched, then the greater was the loss in height relative to the growth rate indicated by younger trees. A dense stand has less reduction in height for a given loss of main stem dominance than does a more open stand. This dependence of the height-diameter relation upon the form of the tree, 56 Figure 4.a.l Site tree form follows growth pattern of younger trees Figure 4. a. 2 Site tree form agrees with "flattened" growth curve } igure 4. a. 3 Site tree form holds height below "flattened" growth curve 57 especially in the large diameters, made the height-diameter curve for a plot include a large judgment factor for the larger diameter trees. A picture was taken of most "site trees" and the height-diameter curve was weighed somewhat by the estimated depression of the height because of form. Figure 4. a. 2 shows a form that puts the tree on the curve if it becomes flattened after 14 inches in diameter while Figure 4. a. 3 shows a form that drops the tree well below even a flattened curve. As an example, on one plot the "site tree" was 41 feet tall, yet there were no trees above 34 feet even though they had larger diameters. In this instance the curve of height-diameter was flat because of the many short larger diameter trees, but the tall "site tree" with its single main stem to the top agreed with the projection of the trend of the younger trees. The height of the height-diameter curve was recorded for 6, 10, 25 inches diameter at one foot above the ground for every plot during the winter of 1964-5, A multiple correlation was run using the heights at 6 inches as the dependent variable and 33 site characteristics as independent variables. The analysis was repeated using the heights at 10 inches and again for heights at 25 inches. The independent variables explained 59% of the variation in height of the pinyon pines at 10 inches in diameter, 57% of 6 inches, and 52% at 25 inches. An ana¬ lysis of the relationship between the heights on the curves at 10 inches and 12 inches with the data of two years showed a 98% correlation. The smallest dia¬ meter that is compatable with reliability should be selected for use in estab¬ lishing the site index because smaller trees are more frequent than the larger ones- In conclusion, the site index diameter will be 10 inches at one foot above the ground line and site index is defined as the height to which a tree will grow on a particular site in the time it will take the tree to each 10 inches diameter. The height-diameter curves of each plot were traced on a common transparency by species and the curves of each province were traced on separate sheets. A family of site index curves was constructed for each species and for two of the provinces. Several trials attempting to compromise the flattened curves with the continuously rising curves produced site index readings at variance with some strong plot curves. After the decision to accept the continuously rising curves as the basis for determining the site index of a plot, the differences among the provinces were eliminated. A single family of site ihdex curves are presented for use with the two species of pinyon and applicable to the entire study area (Figure 4. a. 4). In using the site index chart, a transparent piece of graph paper with the same scale as the chart is used for plotting the heights over diameters for trees of various diameters distributed over the site for which the site index is needed. A free hand curve should be sufficient to match the appro¬ priate site index curve when the transparency is laid on the site index chart. The more dominant the main stem of a tree, the more reliably is it likely to indicate the site index. The broken lines that take off from the site index curves represent the flattening that commonly occurs, and caution is urged in interpreting such curves. On poor sites, young trees often grow as fast as on good sites. It is probable that the young trees do not reflect the limitations of the site which the older trees do. Trees smaller than 6 inches in diameter are too erratic to be sensitive indicators and in some instances the same may almost be said for the very large diameters. It would be confusing to have two site indices for a given area — one for pinyon and one for juniper. In addition, pinyon grows more uniformly on all sites, and is more likely to have a well developed single stem for a more accu¬ rate measurement of diameter and a more sensitive site index curve. Pinyon domi¬ nates the majority of the pinyon- j uniper type within the study area. For these reasons, in addition to the greater erraticness shown by juniper when growing mixed with pine, there is only one site index offered for the type-pinyon site index. The pinyon site index is used even for pure juniper sites by converting the height of the 10-inch juniper from the juniper height-diameter chart 59 (Figure 4. a. 5) to a pinyon site index by applying the correction from the pinyon 10 inch curve- juniper 10 inch curve chart (Figure 4. a. 6). of The family/ j uniper height-diameter curves (Figure 4. a. 5) was constructed in the same manner as the pinyon family and the chart is applicable to juniper throughout the study area. The true relation between Juniperus monosperma and Juniperus osteosperma site curves is not certain because there were too few plots with Juniperus monosperma and their height-diameter curves could not be distin¬ guished from those of Juniperus osteosperma. The other junipers that were found on occasional plots — J_. scopulorum and _J. deppeana — had similar curves, but each curve was based on too few points for reliability. 4.b. Height-Age and Diameter-Age Curves by Site Indices, Species and Provinces — T. W. Daniel The annual rings of each cross-sectional disk from a range of diameters on each plot were counted. There was a total of 2401 cross-sections counted on three radii each. Pinyon annual rings were readily counted. Annual rings on juniper disks were difficult to count in spite of a good sanding technique; however, one person counted the bulk of them, so a reasonable uniformity was achieved in the counts. A preliminary plotting showed no differences in height-age or diameter- age between the two pine species and practically all the Juniper disks were J_. osteosperma. The pine disks were grouped under each’s tree height or dia¬ meter within the site index of the plot from which they were taken. A disk from site index 20 was tabulated in the site index 20 column according to its tree’s height or its diameter. This procedure tended to smooth some of the variation as there could be eight disks from site index 20 which were cut from 16 foot trees. When plotting each point, groups points were weighed more heavily in determining the location of the curve than the more variable single values. The height over age or diameter over age data were plotted within a site index. All the points from groups of three site indices (14, 15, 16, or 17, 18, 60 - (Figure 4. a. 5) to a pinyon site index by applying the correction from the pinyon 10 inch curve-juniper 10 inch curve chart (Figure 4. a. 6). of The family/ j uniper height-diameter curves (Figure 4. a. 5) was constructed in the same manner as the pinyon family and the chart is applicable to juniper throughout the study area. The true relation between Juniperus monosperma and Juniperus osteosperma site curves is not certain because there were too few plots with Juniperus monosperma and their height-diameter curves could not be distin¬ guished from those of Juniperus osteosperma. The other junipers that were found on occasional plots — J_. scopulorum and J_. deppeana — had similar curves, but each curve was based on too few points for reliability. 4.b. Height-Age and Diameter-Age Curves by Site Indices, Species and Provinces — T. W. Daniel The annual rings of each cross-sectional disk from a range of diameters on each plot were counted. There was a total of 2401 cross-sections counted on three radii each. Pinyon annual rings were readily counted. Annual rings on juniper disks were difficult to count in spite of a good sanding technique; however, one person counted the bulk of them, so a reasonable uniformity was achieved in the counts. A preliminary plotting showed no differences in height-age or diameter- age between the two pine species and practically all the Juniper disks were J_. osteosperma. The pine disks were grouped under each’s tree height or dia¬ meter within the site index of the plot from which they were taken. A disk from site index 20 was tabulated in the site index 20 column according to its tree's height or its diameter. This procedure tended to smooth some of the variation as there could be eight disks from site index 20 which were cut from 16 foot trees. When plotting each point, groups points were weighed more heavily in determining the location of the curve than the more variable single values. The height over age or diameter over age data were plotted within a site index. All the points from groups of three site indices (14, 15, 16, or 17, 18, 60 Jw/Jij / ' / X N DE.X 0/ AM E TER AT ON E FOOT ( INC HE 5 30' 5 WEIGHT AT yO 27 1 . 2A‘ te ? I 4-. ji 15 D p. c>5 Pinyon Height at 10" Diameter Figure 4. a. 6. Pinyon-Juniper Height Relationships at 10" Diameter Class* (All Zones) Juniper Height - 10" Diameter * Diameter at 1' above ground level « Y = - log 2.28 + 1.3579 (log X) R2 = 0.968 19 etc.) were balanced around a single curve, then the next higher site indices were plotted and curved. By this means, the relationships shown in Figures 4.b.l through 4.b. 8 were established. Pinyon pine height over age data made strong curves with a reasonable amount of variation around the central tendency. There were less data for the high site index curves and the variation was greater, but the position of the curves was readily determined. Trees in province 2 (La Sal) consistently require a greater age to reach a particular height or diameter at a given site index. This difference between province 2 and provinces 1 and 3 (Esca lante-Sevier and Coronado) is shown in Figure 4.b.l and 4.b.2. The older ages indicated for province 2 do not mean that there were no old trees in provinces 1 and 3, only fewer collected and too few to extend the curves. The tremendous range in the data for the pinyon diameter-age relation is indicated by the broken curves in Figure 4.b,3„ The differences in diameter growth rate between province 2 and provinces 1 and 3 are quite apparent in spite of the wild scatter of some points. Site quality has a real effect on diameter growth within provinces. Juniper shows much the same difference in growth rates between province 2 and provinces 1 and 3 (Figures 4.b. 4 -4.b. 8 ' that was observed for pinyon, but only at the lower heights at 10". On the better sites, the normal trend of increasing growth rate with increase in site quality is reversed in provinces 1 and 3. Diameter growth increases up to a juniper height at 10" diameter of 18' in province 1 (Figure 4.b. 6 ) then decreases with increasing quality of the site. The same effect is observed in province 3 (Figure 4.b. 8) to a lesser degree and is not apparent in Figure 4.b. 7 , The data for the diameter-age relation varied so much that the three provinces were plotted separately. The drop in the height growth rate for the juniper in provinces 1 and 3 (Figure 4.b, 5) on the better sites as well as the more erratic quality of 67 of the juniper data support the decision to refer only to the pinyon site index. In province 2, the juniper height-age relation follows the normal pattern except for the best site. Juniper’s reversed response to site improvement for the height-age and diameter-age relationships could be caused by the increasing aggressiveness of the pinyon on the higher quality sites. This is illustrated by the data of Figure 4.b.6 where the height of the juniper at 10 inches on poor sites is almost the same as the pinyon pine. When the site index increases for pinyon pine, the height of juniper at 10" relative to the pinyon pine's height falls rapidly . 4.c. Tree Height-Crown Diameter and Site Index Correlation — R. J. Rivers The general dependence of tree growth on crown diameter and rate of photo¬ synthesis has become a well-established axiom [Baker, 1950]. More specific association of crown diameter with such characteristics as d.b.h. and tree height probably vary with species, age, and site. Specific studies involving crown diameter-d.b.h. relationships have been carried out on Red Alder [Apsey, 1962] and White Spruce [Vezina, 1962]. One of the studies conducted in even- age spruce stands indicated that the degree of linearity was significant when the areas were divided into site classes [Liebold, 1963] . Crown dimensions and similar characteristics have also been used to predict cone production in such species as Pinus sylvestris [Thorb j arsen , I960]. The main application of crown diameters has been in determination of stand volumes. This relationship has been developed for such species as Populus deltoides and Pinus sylvestris [Ilvessalo, 1950; Berlyn, 1962], More recent utilization of crown diameter-tree volume relationships has been in the field of photo interpretation [Spurr, 1948] . Aerial volume tables for the Pinyon- Juniper Type were developed by Moessner in 1962. This latter work presents 68 of the juniper data support the decision to refer only to the pinyon site index. In province 2, the juniper height-age relation follows the normal pattern except for the best site. Juniper’s reversed response to site improvement for the height-age and diameter-age relationships could be caused by the increasing aggressiveness of the pinyon on the higher quality sites. This is illustrated by the data of Figure 4.b.6 where the height of the juniper at 10 inches on poor sites is almost the same as the pinyon pine. When the site index increases for pinyon pine, the height of juniper at 10" relative to the pinyon pine’s height falls rapidly. 4.c. Tree Height-Crown Diameter and Site Index Correlation — R. J. Rivers The general dependence of tree growth on crown diameter and rate of photo¬ synthesis has become a well-established axiom [Baker, 1950]. More specific association of crown diameter with such characteristics as d.b.h. and tree height probably vary with species, age, and site. Specific studies involving crown diameter-d.b.h. relationships have been carried out on Red Alder [Apsey, 1962] and White Spruce [Vezina, 1962]. One of the studies conducted in even- age spruce stands indicated that the degree of linearity was significant when the areas were divided into site classes [Liebold, 1963] . Crown dimensions and similar characteristics have also been used to predict cone production in such species as Pinus sylvestris [Thorb j arsen , I960], The main application of crown diameters has been in determination of stand volumes. This relationship has been developed for such species as Populus deltoides and Pinus sylvestris [Ilvessalo, 1950; Berlyn, 1962]. More recent utilization of crown diameter-tree volume relationships has been in the field of photo interpretation [Spurr, 1948]. Aerial volume tables for the Pinyon- Juniper Type were developed by Moessner in 1962. This latter work presents 68 > / 45'" * Sirs. I u D & X AGE AT 0*J£ Foot (in ybah% ) p. 69 p. 71 D/am er£‘< a r PtZOV/^C £ S >28' 5 420 Pro v i mce z '/ £8' Sire AT Poor- (YEARS) 4°- 73 * jf. 7S 35 3o Figure 4.. b , 5 PROViWCE. 1 AMO 3 JU M I PER H £ * 6 H T- A p. 7 7 \ 30 15 FIGURE 4. L 6 PROVIMCE I Juniper d i a./ G £ WtioWr A r 10 " - 18' 1 >i&< Wfc « ‘Xv*Jv*r* « !■*■.>«** 1+ttnr’o* IOO Z&o r 300 A6£.atOaj£’ Pcxsr (yz/ws) yco f- 79 3 4 C k t A1 l- 7 '/-A' A T~ O/ygr /~007~' fir/V C \ volume (in cubic feet) and products (fence post) estimates for various crown diameter-tree height relationships [Moessner, 1962]. No attempt was made to stratify this material by site. The possibilities of crown diameter-site interactions have been implied in several studies [Woodin and Lindsey, 1954; Weike, 1963; Liebold, 1963]. This possibility is also discussed by Spurr, who states that since tree height and crown diameter can be measured by aerial photos, it is possible that, under certain conditions, the ratio between tree height and crown diameter will pro¬ vide a measure of site quality. This section presents a consideration of Pinyon-Juniper height-crown dia¬ meter characteristics as related to site. Definitions- i. Tree height: Total height from the ground level to the tip of the dominant stem. Measured to the nearest 0.1 of a foot. ii. Crown diameter: Average width of the tree crown as determined from two diametrically opposite measurements from one extreme tip to the other. iii. Site class: Based on the tree height at the 10" diameter class read from the height /diameter curve for that plot. Site class Ht. at 10" diameter class 1 24' - 31' 2 21' - 23' 3 18' - 20' 4 11’ - 17' iv. Basal area classes: Class B. A. /acre 1 0-61 sq. ft. 2 61-00 sq. ft. Basic data- The data used in the preparation of the height-crown diameter curves were secured from 213 one-tenth acre plots located throughout the five state area. 85 All of these plots were established during the 1964 field season. The measure¬ ments were in addition to those used for collection of site index data. Tree measurements for the present study included total tree height (to the nearest one-tenth of a foot) and crown diameter (to the nearest foot) . Crown diameter measurements were summarized and the mean crown diameter obtained for each tree height class for both pinyon and juniper. These data were further stratified by basal area classes, site classes, and provinces. An analysis of variance was run to determine if any significant difference existed between the means when stratified by the basal area and site classes. A regres¬ sion analysis provided the statistical equation for height-crown diameter relation¬ ships within each province and for all provinces combined. Analysis and discussion- The results of the analysis of variance indicated that no significant difference existed when the data were stratified by basal area classes. There were differences when the data were arranged by sites or pro¬ vinces . Province differences were not strong in the pinyon data. It is more signi¬ ficant to stratify by site. Table 4.C.1 lists the site classes and linear regres¬ sion parameters. The juniper height-crown diameter correlation coefficients improved when the data were stratified by provinces and sites within a province. Table 4.c.2 lists by province and site class the results of the linear regression of juniper heights on crown diameters. Insufficient observations prevented stratification into three site classes per province. More data could increase the values if these pro¬ vinces could have been broken down into three site classes. The height-crown diameter correlations support the notion of definite site indices and confirms Spurr’s statement noted above. It should be realized that the classifications amount to good-fair-poor sites for pinyon and good-poor sites for juniper. 86 Table 4.c.l« Pinyon Sp. ht./cr. diameter regression formulas Site class Regression equation ^2 Ht. observa- Graph tions represented No. in analysis All y = 0.621 + 0 .517 (X) 0.946 4 '-42 ’ Not presented 21 ’-31 ’ y = 2.7159 + 1.6387 (X) 0.984 4 ' -40 ' 4 . c . 1 11 ' -20 ’ y = 1.1286 + 1.4308 (X) 0.935 4 ’ -30 ’ 4 . c . 1 24 1 -31 ’ y = 3.8006 + 1.5979 (X) 0.955 4 ' -40 ' 4 . c . 2 18’-23’ y = 1.2640 + 1.5804 (X) 0.969 4 '-32' 4 . c . 2 11 ’ -17 ’ y = 1.2879 + 1.2356 (X) 0.968 4 ' -24 ' 4 . c . 2 Table 4. c.2. Juniper Sp. height/crown diameter regression formulas Site class n ^ . Ht. classes Correlation _ Province Regression equation coefficient represented in analysis Graph No. All All y = 1.918 + 0.487 (X) 0.825 4 ’ -33 ' Not pre¬ sented All 1 y = 1.051 + 0.778 (X) 0.954 4 ’ -24 ' Not pre¬ sented 21 ’ -31 ' 1 y = 2.767 + 1.262 (X) 0.957 4 ' -28 ' 4 . c , 3 11 ' -20 ’ 1 y = 1.874 + 1.163 (X) 0.991 4 ' -25 ' 4 . c . 3 All 2 y = 0.279 + 0.587 (X) 0.920 4 ' -24 ' Not pre- sented 21 ’ -31 ’ 2 y = 1,791 + 1.746 (X) 0.903 4 ' -24 ' 4 . c . 4 11 ' -20 ’ 2 y - 0.371 + 1.307 (X) 0.946 4 ' -23 ’ 4 . c . 4 All 3 y = 0.366 + 0.746 (X) 0.890 4 ' -24 ’ Not pre- sented 21 ’ -31 ’ 3 y = 2.939 + 1.146 (X) 0.943 4 ' -24 ' 4 . c . 5 11 ' -20 ' 3 y = 2.074 + 0.907 (X) 0.929 4 ' -22 ' 4. c. 5 87 Exhibits 4.C.1 through 4.C.5 graph the equations presented in the previous tables. The height classes represented in these exhibits have been extrapolated beyond the observations used in the regression analyses. This allows for any combination of height-crown diameter for a given site index. In all cases the greatest amount of variation was found in the upper height classes. This is probably what would be expected and this phenomenon has been recorded in growth studies of Utah junipers [Baker, 1950]. The same situation probably exists in both Pinus monophylla and Pinus edulis . The longevity (600 years) of these trees plus the adverse climatic conditions under which these species exist all explain a reduction or die-back in total height in overmature age classes. Recommendation- In the event of future on-the-ground site evaluation , crown dia¬ meter-height relationships can be used as a cross check with tree height to make sure that the sample area is on the desired site class. This application of crown diameter association was used by Woodin and Lindsay in their study of P-J east of the Continental Divide [1954]. If suitable photos are available, it should now be possible to inventory P-J stands not only by height classes, but also by site indices. For this pur¬ pose, curves 4.C.1, 4.C.3, 4.C.4, and 4.C.5 should be used. These curves repre¬ sent site indices divided into 10? height classes. During initial application of these data, some difficulty might be encountered since crown diameter measure¬ ments by photos are usually smaller than comparable ground measurements. The value of these data will depend on the skill of the photo interpreter and the quality of the photos being used. 88 Figure 4.c.l Pinyon Height-Crown Diameter Correlation All Provinces 1° 4J •H C 0 00 CNI CvJ co i O o c CD 3 *H 3 5 > 3 0 0 00 5-i S-i •H U P-i Pk x oo •H ‘“3.^ .. sms “ s.“ 25 * »■ Average profile composition - The following textures „• numbers from 1+9 increasing wiH! • . tures were given ’ increasing with increasingly heavy soils: Gravel i Sand 2 Sandy loam 3 Loam 4 Silt loam 5 Silt 6 Clay loam 7 Silty clay loam 8 Clay 9 l . Calculated available moisture of nrofilp — composition was compared to a "soil texture-moisture8^ M1 "llS curve prepared from information found in Soil Surve t mH\ The available moisture per foot of profiles taknn f - curve and multiplied by the number of feet in the profile j. Field estimate of moisture holding capacitv - for *n" Estimated in the field. Y °T 60 soll‘ 102 k. Soil permeability - Classes Rate Slow 0.05 - 0.20 Moderate 0.20 - 5.0 Fast 5.0 - 10.0+ Classes assigned were taken from field sheets with rapid and very rapid categories combined. Structure, consistence, and plasticity are involved in this determination. 1. Surface texture - This was recorded with reference to increasing weight in the surface horizon from 1 9 using the values previously assigned . m. Rock on surface - n. Rock in upper profile o . Rock in lower profile These were rated from 1 -> 5 , with increasing rock represented by decreas¬ ing numbers, as follows: Percent of rocks were those 2 mm and larger. 1 - 60% + rock 2 - 30-60 " 3 - 10-30 M 4- 0-10 " 5- 0% rock p. Depth to clay layer - Depth measured to nearest inch from soil surface to first clay textured horizon as: Silty clay Sandy clay Clay In soils having no clay, this depth is recorded as the depth to bedrock. q. Total root depth - Root depth to nearest inch as closely as could be determined from data available on field sheets. r. Depth of profile - Total depth, to nearest inch, by shovel or by auger. Dependence of roots on fractures in bedrock - rated from 1 -> 5 as follows: Extremely dependent - 1 Highly dependent - 2 Moderately dependent - 3 Light dependence - 4 No dependence - 5 s. Low aeration depth - Depth measured from surface to either a heavy clay horizon, cemented horizon, or consolidated bedrock. t. Depth of soil below low aeration - The depth of soil between the top of the low aeration zone and bedrock materials. u. Material underlying low aeration zone - Underlying materials '‘CH horizon code Bedrock code Eolian sand 1 Loess 2 103 Bedrock code Underlying materials Fine alluvium Coarse alluvium Tertiary sediments Lacustrine material Decomposing bedrock Bedrock Sandstone Limestone/ dolomite Basic igneous Shale "C" horizon code 3 4 5 6 7 8 Metamorphic rock Acid igneous Undifferentiated material Material continuous from "C" horizon 1 2 3 4 5 6 7 8 Nature of Bedrock Fractured Consolidated Unknown Code 1 2 3 v. Soil lime above low aeration depth and soil lime below low aera¬ tion depth - w. PH @ Surface of profile (determined for uppermost horizon) , pH immediately above low aeration - (determined for horizon imme¬ diately overlaying horizon containing low aeration zone) , pH below low aeration (determined as the highest pH measured for the horizons between the low aeration layer and bedrock. If there was no low aeration zone, the pH used was the same as determined for the pH immediately above the low aeration zone.) x. Profile normality - A profile was considered normal when soil texture became heavier in texture with depth. y. Color of surface soil and color of upper profile - 1964-65 Plots — After considering the results obtained from analyzing the soil- site data from the 1964 plots, a decision was made to continue using only the most significant factors. Some additional variables were added in an attempt to improve reliability. The final list was as follows: a. Stand density - Where very dense stands were rated (1) and very open stands were rated (9) . b. Evaporation rate - Evaporation rate for each site from U.S.G.S. Prof. Paper 272-D. c. Total precipitation/evaporation rate - d. Depth to low aeration - 104 e. Profile depth - f. Moisture holding capacity - Field estimate g. Dependency of roots on bedrock - Rated (1) to (9) on the fol¬ lowing basis: (1) Bedrock highly fractured, large and medium roots observed going into fractures; (2) to (4) Bedrock frac¬ tured, small or medium roots present in fractures; (5) to (6) Bedrock is not highly fractured, very few roots observed in fractures; (7) to (8) Bedrock appears to be infractured and/or is well below root zone; (9) Bedrock deeper than 60" or absent. h. Percent rock in profile - Percentage of the soil volume occu¬ pied by rock in that portion of the profile not considered bedrock which may have some effect on tree growth and water relationships within the soil. i. Depth to change in total soluble salt concentration - Profiles where no difference is noted or where TSS figures are higher in upper horizons are rated 0. j . Average TSS - Weighted average of TSS concentration in that portion of profile above the highest concentration of TSS. k. Highest TSS - Value which expresses the highest TSS concentra¬ tion found in each soil profile. l. Lime - present or absent. m. Depth to sharp change in lime concentration - n. Texture - Weighted average texture class estimated for the root zone of each profile. Gravel and coarse sand were con¬ sidered as part of this textural classification. Ratings were from (1) to (8), with the smaller numbers designating the lighter textured soils. o. Total precipitation - p. Summer precipitation - q. Winter precipitation - r. Profile development - Rated from 1 to 5 based on presence or absence and the degree of development of the B horizon. s. Elevation - t. Latitude - u. Longitude - v. Total basal area per acre (tree stems) - w. Province - 1. Escalante-Sevier ; 2. La Sal; 3. Coronado. 105 x. Total average July and August precipitation - From Weather Bureau summaries for stations located nearest to each plot. 5.b. Statistical Analysis of Soil Plot and Climatic Data of 1964/1965 Plots E. J. Eberhard and A. LeBaron A "step-wise" regression analysis was performed using pinyon height at 10", D.B.H. as the dependent variable and 33 selected soil and site character¬ istics as independent variables . ^ The 212 plots were located within pinyon- juniper stands throughout the five state study area. No attempt was made to stratify the data by recognizable geographical, climatic, or edaphic character¬ istics. All data were from 1964 field sheets. The model chosen assumes that all relationships are linear. In addition, the possible effect of interaction between the independent variables was not considered. A coefficient of determination (R"1) of 0.587 was obtained using all 33 variables. The results are summarized in Table 5.b.l. The variables are listed from top to bottom in the order that they dropped from the predic¬ tive model. The variables of the bottom of the list are the most significant in explaining variation in pinyon site quality. The last 8 variables in the list, winter precipitation, dependency of roots on bedrock, surface runoff, depth of profile, depth of soil below aeration, depth below aeration, total depth, and summer precipitation explain 41 percent of the variation in pinyon site quality. Table 5.b.2 shows "f" values and regression coefficients (6) for the eight residual variables. The estimating equation is summarized at the bot¬ tom of the table. It will be noted that the "f" test values show all vari¬ ables except one, to be significant at the 0.01 level. 1964-1965 Plots — The data from all the tree sit£s sampled during the course of the study were stratified into three ecological provinces. The basis for iFor description of the computer program, see Section 7.d. 106 Table 5.b.l. Step-wise regression analysis of 1964 plots Variable Coefficient of determination R 2 Ecological orientation Profile normality Lime-above Profile composition Color - upper Lime - below Rocks - upper pH - surface Rocks - lower Calculated available moisture Depth to clay Soil stability Percent slope Slope character Elevation Surface texture Permeability Slope position Rocks - surface Material - below surface pH - below pH - above Color -surface Moisture holding capacity (est.) Total precipitation Winter precipitation Dependency on bedrock fracture Surface runoff Profile depth Depth - below low aeration Depth to low aeration Total root depth Summer precipitation x6 0.587 X31 0.586 X26 0.585 Xll 0.581 X33 0.579 x27 0.574 x17 0.573 x28 0.571 x18 0.564 X12 0.561 x19 0.552 x10 0.551 X5 0.550 x7 0.547 x4 0.543 x15 0.542 ! - 1 X 0.542 x8 0.516 X16 0.510 x25 0.501 x30 0.496 x29 0.484 x32 0.465 x13 0.465 X1 0.443 x3 0.413* x22 0.360* x9 0.336* X21 0.304* x24 0.220* x23 0.217* x20 0.201* x2 0.093* *These variables explain 41 percent of the variation in pinyon site quality. 107 Table 5.b.2. Summary - residual variables. 1964 plots Residual variable name and number (R2 = "f" value 41.3%) 6 Winter precipitation (3) 13.68 0.526** Dependency on bedrock fractures (22) 6.86 -0.627** Surface runoff (9) 6.26 0.200* Profile depth (21) 25.64 0.443** Depth - below low aeration (24) 24.86 -0.445** Depth to low aeration (23) 28.45 -0.495** Total root depth (20) 21.00 0.165** Summer precipitation (2) 7.98 0.484** Estimating equation: yq = 10.41 + 0.526 X3 _ 0.627 X22 + 0.200 X9 + 0.443 X21 ~ 0.445 X24 “ 0.495 X23 + 0.165 X20 + 0.484 X2 **Signif icant at 0.01 level. ^Significant at 0.05 level. developing these provinces is discussed in Section 3.b of this report. A step¬ wise regression analysis identical to that performed on the 1964 plots was made with the tree site data for each province. The number of independent variables was reduced to 22 for this analysis and somewhat better results were obtained than with the more general 1964 model . When all the variables were included, they explained 61.2 percent of the variation in site quality within the Escalante-Sevier province, 53^1 percent of the variation in site quality within the La Sal province, and 64.7 percent of the variation in site within the Coronado province. A model composed of "residual" variables was chosen to provide an esti¬ mating equation for each province. The set of residual variables differed in every instance. Summaries of the results from each province are reported in Tables 5.b.3, 5.b.4, and 5.b.5. 108 Table 5.b.3. Summary - residual variables, Escalante-Sevier province, 1964-65 plots (R2 = 49.3%) Variable name and number "f" value 3 Longitude (22) 4.79 0.057* Depth to low aeration (9) 7.97 -0.124** Precipitation/evaporation (8) 12.48 0.243** Evaporation (7) 10.26 0.265** Depth to change in lime (18) 15.07 0.128** Lime-present or absent (17) 8.66 2.652** Stand density (6) 21.32 -0.923** Estimating equation: yi = 0.655 + 0.057 X22 " 0*124 X9 + 0.243 Xg + 0 . 265 X7 + 0.128 X18 + 2*652 X17 ■ - 0.923 x6 **Signif icant at 0.01 level. ^Significant at 0.05 level. Table 5.b.4. Summary - residual variables. La Sal province, 1964-65 plots (R2 = 45.3%) Variable name and number "f" value 3 Depth to low aeration (9) 6.47 0.062* Precipitation/evaporation (8) 13.15 0.142** Latitude (25) 11.01 -1.610** Moisture holding capacity (11) 15.28 -0.989** Stand density (6) 16.52 -0.685** Estimating equation: y^ = 27.329 + 0.062 Xq + 0.142 Xg - 1.61 X25 - 0.989 Xlx - 0.685 X6 **Signif icant at 1.01 ^Significant at 0.05 level . level . 109 Table 5.b.5. Summary - residual variables, Coronado Province, 1964-65 plots (R2 = 54.9%) Variable name and number "f" value 6 Profile depth (10) 6.66 0.048* Stand density (6) 17.08 -0.902** Total precipitation (20) 15.67 0.523** Basal area (23) 10.99 0.029* Profile development (19) 18.44 -1.250 Estimating equation: y^ = 20.73 + 0.048 X10 - 0.902 X^ + 0.523 X2Q + 0.029 X23 - 1.250 X19 **Signif icant at 0.01 level. ^Significant at 0.05 level. Discussion and Analysis — In order to isolate highly significant site factors in a study of this kind, it is necessary to explore the various factor inter¬ actions which are thought to influence the soil-moisture regime and other im¬ portant growth controlling systems. An analysis such as that reported by Hurst and Pederson [1964] conceivably could yield excellent coefficients of determination. But unless one is willing to experiment with a range of values for every element of each introduced interaction term, the points at which the interrelationships become critical remain a mystery. Any attempt to use an estimating equation involving such terms may be dangerous; prediction of site- quality in a particular instance might involve values of interaction elements that would result in negative height estimates, etc. Such cases require estimating equation adjustments based on knowledge of interaction term opera¬ tions and some developed theories of the interactions themselves. This latter point is important. Unless such theories or hypotheses exist, and are defen¬ sible, it is difficult to make any statement about what is or is not being explained. 110 Nevertheless, some guesses were made concerning possible interaction terms and these were introduced as additional variables. The soil and site data were then run through the same "step-wise" regression program (but on 4 a larger computer) . No worthwhile improvements in coefficients of determi¬ nation were obtained. Given the time and effort that would have been neces¬ sary to hypothesize and refine more sophisticated interactions, it was decided to rely upon only the linear model discussed above. The results of that model are plausible, and since the estimating equa¬ tions for each province (supra) imply somewhat simpler relationships than those reported in Section 7.d (in connection with grass yield), there may be some temptation to place too much faith in them. Fieldmen and administra¬ tors would realize that the cross-sectional site data undoubtedly exhibit multicolinearity and if certain critical (but unsuspected) values for site variables are introduced, the results will be unreliable. At the same time, it should be recognized that the relationships featured in the present study should provide definite insights for future soil-site research on pinyon pine. a. Escalante-Sevier - Eight variables explain 49.3 percent of the varia¬ tion in site quality. These variables in ascending order of importance are: longitude, depth to low aeration, precipitation/evaporation, evaporation, depth to change in lime, lime-present or absent, and stand density. As the value for longitude increases from east to west, the site quality appears to go up. There is a possibility that the pattern of sampling loca¬ tion may have produced this result. As the depth to low aeration increased, the tree site quality decreased. The implications to this are not clear. The analysis indicated that as precipitation/evaporation ratio and evapora¬ tion rates increase, site quality should increase. Depth to change in lime is an indirect measure of the effectiveness of precipitation. Since the soils in this province are usually gravelly in texture, the positive 111 relationship between an increase in the depth to lime, and an increase in site quality is probably valid. Absence of lime in the profile seems to indicate a higher site quality. This conclusion should be received with serious reser¬ vations until further studies are made. Stand density, which increases with an increase in site quality, is a valid expression of several soil and climatic interactions . b. La Sal Province - Five variables explain 45.3 percent of the variation in tree site quality. These variables in ascending order to importance are: depth to low aeration, precipitation/evaporation, latitude, moisture holding capacity, and stand density. With an increase in the depth to low aeration, tree site quality improves. This relationship appears to be valid considering the variation in soil tex¬ tures throughout the province. As the precipitation/evaporation ratio increased the site quality increased. This result indicates that rainfall is more effec¬ tive in areas of low potential evaporation. This same relationship is reflected in the latitude variable, because potential evaporation rates are lower at the northern end of the province. As in the Escalante-Sevier Province, stand density is highly correlated with site quality. c. Coronado Province - Five variables explain 54.9 percent of the varia tion in site quality. These variables in ascending order of importance are: profile depth, stand density, total precipitation, basal area, and profile development . As depth of profile increased, site quality increased. As in the other two provinces, an increase in stand density indicated an increase in site quality. Basal area, which is a property of density, also increases on the better sites. The Coronado province, because of its geographical location, probably has a longer annual growing season than the other provinces. For this reason, it is safe to assume that total precipitation and profile 112 development, which are functions of precipitation, are useful variables in predicting site quality (because moisture can be utilized during a longer period throughout the year) . i 5.c. Chemical Properties and Site Productivity — E. J. Eberhard A representative sample of each horizon in the soil profiles described during the course of the study was collected for laboratory analysis. Because of the large number of samples involved, and the obvious limitations of time and money, it was not possible to examine all the chemical properties of the soil which might have proven useful in predicting potential site productivity of pinyon-j uniper lands. Almost all of the research reported in this section shows negative results. Statistical analysis of the data has not treated every possibility. This must be borne in mind when evaluating possible interactions between soil chemical factors and soil physical factors as well as the contention regard¬ ing negative results. It is assumed that the information reported here will be of value in future studies. Effect of Other Site Factors on Chemical Properties — There are several varia¬ bles which cannot be accurately treated in terms of their possible effects on the relation of soil chemical properties and site productiveness. Probably the most important are differences in parent material. Della-Bianca and Olson [1961] stress the importance of conducting soil-site studies on a local geographical basis and on uniform parent materials. Many researchers [Carmean, 1956; Myers and Van Deusen, 1960; Zinke, 1959] have stratified soil-site data into parent material groups and have found that parent material exercises con¬ siderable influence on site quality. Lutz [1958] points out differences within parent materials. In most studies, differences in site quality attri¬ buted to parent material, are linked to differences in soil depth and texture 113 rather than chemical differences. However, Forristall and Gessel [1955] and Youngberg and Scholz [1949] have placed emphasis on the importance of soil chemical properties to tree growth. Texture of a soil profile has a pronounced effect on chemical properties. The texture determines to a large degree the leaching and soil development that will take place in a given soil profile. It is quite possible that small textural differences could result in signifi¬ cant chemical differences between two profiles which have been classified as being similar in texture. Adequate sampling is difficult. It is common knowledge that the chemical state of soil is dynamic, and that significant differences exist among soil samples taken in the same immediate area. Certainly this possibility should be considered in the present study where it has been necessary to represent an entire tree or grass site with a single soil sample. (The effect on vegeta¬ tion of differences in chemical properties will be discussed later in this section . ) It is also recognized by most soil scientists that present laboratory procedures and the results obtained do not always reveal key variables in soil-chemical relationships [Millar, 1955]. Probably the best example of this situation is in determination of available nitrogen for crop growth. In an extensive study such as this, there must be many other site factors which would exert a confounding influence on the utilization of chemical pro¬ perties of soil for predicting site productivity. However, there is evidence that the use of both physical and chemical soil factors in an intensive study of a localized area would be of value in predicting site productivity differences. Selection of Soil Tests — Natural soil fertility of the arid, relatively un¬ leached soils of the pinyon- juniper zone would appear to be too high to limit plant growth. Tarrant [1949] found in Douglas fir, which occupies sites in 114 higher precipitation zones than pinyon, that moisture availability was the limiting growth factor, not soil fertility. For this reason, it was decided to concentrate on tests which might show that growth was limited by an excess or presence of a certain chemical condition. Gates, Stoddart and Cook [1956] have shown that the concentration of soluble salts, exchangeable sodium, and related soil conditions influence the distribution pattern of some desert vegetation. An attempt was made to determine the degree and depth to which a profile had been leached by comparing the chemical content of the various horizons. This information was related to available rainfall data [Jenny, 1931] . Jenny and Leonard [1934] used the depth to lime carbonate concentration as an indi¬ cator of rainfall in loessial prairie soils from Colorado to Kansas. They also obtained good relationships correlating increasing rainfall with higher colloidal clay content of surface, lower soil pH, higher percent nitrogen, and higher cation exchange capacity. They stress the fact that uniform vege¬ tation, preferably grassland, and uniform parent material are necessary for successful leaching estimates. After considering the time and funds available, it was decided to run a preliminary study on the soil samples from 13 plots. Each horizon sample was analyzed for total soluble salts - (TSS) , electrical conductivity of the saturation extract - (ECe) , total sodium - (TS) , and total potassium - (K) . All tests were made in the Utah State University Soil Testing Laboratory according to procedures outlined in the U.S.D.A. Agriculture Handbook No. 60, "Diagnosis and Improvement of Saline and Alkali Soils." The Wheatstone bridge was used to determine the approximate salt content of the soil as expressed by TSS and ECe. The flame photometer and the prescribed extraction techniques were used to measure TS and K. 115 Preliminary Study— The thirteen (1964) tree plots selected for the preliminary study represented four of the best tree sites, three of the poorest sites, and six medium sites. All these sites had soil profiles which were deeper than 25 inches, and fractured bedrock conditions did not appear to be a possible site factor. Five of the sites had sandstone parent material, two had coarse alluvium parent material, three had limestone parent material, and one site each had loess, shale, or acid igneous parent material. Soil pit elevations ranged from 5600 feet to 8100 feet, and sites were scattered over the entire study area. TSS, ECe, and TS values were obtained for each horizon, and the values were plotted against depth. Observed tree root conditions were taken into account by drawing perpendicular lines from the "depth axis of each site graph (Figure 5.C.1). Values of TSS ranged from less than 0.03 to 0.45 percent. ECe values ranged from 0.435 to 10.038. TS values ranged from 0.15 me/liter to 3.30 me/ liter. In all cases, the higher values are associated with higher salt or sodium concentrations. Examination of the profile graphs led to the following conclusions. i. The concentration of total soluble salts as measured by TSS (Resis¬ tance through a Bureau of Soils Cup), EC0 (Conductivity of the extract of a saturated soil), and TS (Total sodium, as determined by the flame photometer) showed the same curve form within each profile. ii. High salt or sodium concentration within any horizon of the profile, including the major root zone appeared to have no relation to tree growth on a site. However, physical factors such as cementation which accompany high salt concentrations in some cases may be a limiting factor. iii The use of salt or sodium concentration to measure the depth of leaching or water movement has limited value because these salts have a 116 t LO . o CO <3 x a C3 d d •H o 4-1 T— 1 4-1 ON T3 CO i—H <3 VO r— 1 T3 1 <3 1 - 1 <3 d i <4-4 •H cd d • <4-1 CO o o o -d 1 •H d (3 <3 i — 1 5 - 1 U 03 W cd d M-i n d < LO <3 j-i 3 00 •H CO ■u> o O 5-i > (3 5-1 <3 > O X 0 R » CM &K CO <4-4 4-1 •H O 4-1 o d cd C3 T— 1 a o "X. O /. CO C3 CO CO O H EH w 4» xT o uopFa^uaouoo uinxpos pue iix^S 117 Depth-feet tendency to move rapidly through the profile in response to precipitation or evaporation. In several of the profiles, salt and sodium concentration was highest at the surface, or was evenly distributed throughout the profile, even when rainfall information, profile development, texture, and lime con¬ centrations indicated that substantial leaching had taken place. iv. Comparing only those profiles derived from sandstone parent material, it was found that depth to the highest salt or sodium concentration was weakly correlated with site classification. All these profiles were similar in tex¬ ture, and with this factor constant, an indication of usual wetting depth was obtained. As has been observed in the soil-site portion of this section, depth to lime carbonate appears to be a more reliable measure of leaching depth [Jenny and Leonard, 1934], Since the TSS concentration of a soil sample can be determined in a much shorter time than either ECe or TS, TSS was measured for a maximum of four horizons within each tree site soil profile. TS and K were determined for the two horizon samples from selected soil pits which had been established on the tree control sites. Total soluble Salts and Site Productivity — Using all the tree plots, results were similar to those of the preliminary study. No correlation appeared between high TSS and tree growth on the hand-drawn scatter diagrams. Appa¬ rently rainfall and drainage throughout the pinyon-j uniper type are adequate to prevent toxic or growth limiting concentrations of total soluble salts. Scatter diagrams were made for profiles classified into six textural classes. Weak correlations between depth to highest TSS concentration and tree height growth were noted only on the medium textured soils. This corre¬ lation was further strengthened by stratifying profiles into four precipitation classes. However, the number of observations in each of these strata was 118 probably not sufficient to give a statistically reliable estimate of the correlation . The results from the heavy and light textured soils, as well as the 4 very rocky or gravelly soils, showed no correlation between tree growth and depth of leaching as determined by depth to the highest TSS concentration in the associated profiles. Soil samples from the A1 and B or AC horizons found on tree control pro¬ jects were analyzed for TSS and K in an attempt to relate these chemical pro¬ perties to grass production. Projects located in Esca lante-Sevier province that had been windrowed and drilled, and projects in the La Sal province where the trees had been chained, seed broadcasted, and rechained, were considered. It was impossible to show even weak correlations between grass production and/or establishment, with either TSS or K concentration in the surface or underlying AC or B layer. Stratification by parent material, texture or rainfall did nothing to improve the relationships. Comparison of TSS Concentration within Tree Stands and on Adjacent Tree Con¬ trol Projects — When TSS concentration of the surface horizons of the paired tree and tree control sites were studied, several interesting relationships were discovered. On medium, deep, non-rocky, and non-gravelly sites, the TSS concentration of the surface horizon of the tree control site was sig¬ nificantly lower than that of the tree stand site. On heavy or light tex¬ tured soils the difference was not significant, and most of the time TSS concentrations were the same. This condition would imply that water infil¬ tration is greater on the tree control sites. However, it must be remem¬ bered that the soil sample from the tree stand sites came from an area which was under the crown of the site tree. The interspaces were not sampled. The pinyon-juniper stands on the Hualapai Indian Reservation in north¬ western Arizona were burned in place, and then broadcast seeded. It was 119 found on nearly all of these projects that the TSS concentration was higher on the burned areas than within the undisturbed tree stands. The grass stands on these projects were very productive and vigorous, relative to projects with similar climatic and soil conditions. Apparently the heat of the fire was not intense enough to destroy soil nutrients, but raised fertility by releasing minerals from existing litter and tree growth. 120 REFERENCES Arnold, J. F. , D. A. Jameson, and E. H. Reid. "The Pinyon-Juniner Type of Arizona: Effects of Grazing, Fire, and Tree Control. Production Research Report No. 84, U.S.D.A., Forest Service, 1964. Baker, F. S. "Stand density and growth." Journal of Forestry 51:95-97. 1953. Bassett, John R. "Tree growth as affected by soil moisture availability." Soil Science Society of America Proceedings 28:436-438. 1964. Boyce, J. S. Forest Pathology. McGraw-Hill Book Co., Inc., 3rd Edition, New York, Toronto, London, 1961. Campbell, R. S. and Roger W. Rich. "Estimating soil moisture for field studies of plant growth." Journal of Range Management 14:130-134. 1961. Carmean, W. H. "Soil survey refinements needed for accurate classification of black oak site quality in southeastern Ohio." Soil Science Society of America Proceedings 25:394-397. 1961. _ . Suggested modifications of the standard Douglas-fir site curves for certain soils in southwest Washington. Forest Science 2:242-250. 1956. Chapman, H. H. and C. E. Behre. "Growth and management of piny on in New Mexico." Journal of Forestry 16:215-217. 1918. Coile, T. S. "Soil and the growth of forests." Advances in Agronomy 4: 329-398. New York: Academic Press Inc., 1952. Coile, T. A. "Relation of soil characteristics to site index of Loblolly and Shortleaf Pines in the lower Piedmont region of North Carolina." Duke University School Forestry Bulletin 13, 78 pp . 1948. Della-Bianca , Lino and David F. Olson Jr. "Soil-site studies in Piedmont hardwood and pine-hardwood upland forests." Forest Science 7:320-330. 1961. Dixon, H. "Ecological studies on the high plateaus of Utah." Botany Gazette 97:272-320. 1935. Doolittle, W. T. "Site index of scarlet and black oak in relation to southern Appalachian soil and topography." Forest -Science 3:114-124. Eis, S. "Statistical analysis of several methods for estimation of forest habitats and tree growth near Vancouver, B.C." University of British Colum¬ bia, Forestry Bulletin No. 4, 1962. Forristall, F. F. and S. P. Gessel. 1955. "Soil properties related to forest cover type and productivity on the Lee Forest, Snohomish County, Washington." Soil Sci. Soc. Am. Proc. 19:384-389. 121 Gardner, R. A. "Soil-vegetation associations in the redwood-Douglas-f ir zone of California." Michigan State University Agriculture Experiment Station. First North American Forest Soils Conference, pp . 86-101, 1958. Gardner, R. A. and W. H. Lyford. "The status and needs for soil survey in forested land." Soil Science Society of America Proceedings 19:91-93. 1955. Garland, L. E. , R. S. Pierce and G. R. Trimble Jr. "A soil survey of forest land." Journal of Soil and Water Conservation 14:199-204. 1959. Gates, D. H. , L. A. Stoddatt, and C. W. Cook. 1956. "Soil as a factor in¬ fluencing plant distribution on salt deserts of Utah." Ecology Mono. 26:155-175. Herman, F. R. "Growth and phenological observations of Arizona junipers." Ecology 37:193-195. 1956. Howell, Joseph Jr. "Pinyon and juniper woodlands of the Southwest." Journal of Forestry 39:542-545. 1941. Hurst, R. L. and M. W. Pedersen. "Alfalfa seed production as a function of genetic and environmental characteristics." Advancing Frontiers of Plant Sciences 8:41-54. 1964. Jameson, D. A., J. A. Williams, and E. W. Wilton. "Vegetation and soils of Fishtail Mesa, Arizona." Ecology 43:403-410. 1962. Jenny, H. 1931. "Behavior of K and Na during the process of soil formation." Mo. Agr. Expt. Sta. , Research Bulletin No. 162. Jenny, H. "Derivation of state factor equations of soils and ecosystems." Soil Science Society of America Proceedings 25:385-388. 1961. Jenny, H. Factors of Soil Formation. New York, McGraw-Hill, 281 pp . , 1941. Jenny, Hans and C. D. Leonard. "Functional relationships between soil pro¬ perties and rainfall." Soil Science 38:363-381. 1934. Kittredge, J., Jr. "The interrelations of habitat, growth rate, and associated vegetation in the aspen community of Minnesota and Wisconsin." Ecol. Mono. 8: 151-246. 1938. Klemmedson, J. 0. "Topogunction of soils and vegetation in a range landscape." American Society of Agronomy Special Publication No. 5, pp. 176-186, 1963. Klemmedson, J. 0. and R. B. Murray. "Range research methods." Miscellaneous P ub 1 1 c a 1 1 on No. 940, U.S.D.A., U. S. Forest Service, 1963. Kramer, P. J. and T. Kozlowski. Physiology of Trees. New York, McGraw-Hill Book Co., Inc., 1960, 642 pp. Kreis, E. A., F. A. Bennett, and A. E. Patterson. "A site prediction test in slash pine plantations in the middle coastal plain of Georgia." U.S.F.S., S. E. Forest Experiment Station, Research Note 93, 2 pp., 1956. 122 Landsberg, H. E. Weather, a factor in plant location. U. S. Department of Commerce, Weather Bureau, May 1961. Little, E. L. "Common insects on pinyon." Southwest Forest and Range Experi¬ ment Station, Research Note 110, 1944. Locke, S. S. "The use of soil-site factors in predicting timber yields." Soil Science Society of America Proceedings 6:399-402. 1941. Lutz, H. F. "Geology and soil in relation to forest vegetation." In First No. Amer . For. Soils Conference, Michigan State University, East Lansing, pp. 75-85, 1958. Major, Jack. "A functional, factorial approach to plant ecology." Ecology 32:392-412. 1951. Mann, W. F. Jr., and L. B. Whitaker. "Stand density and pine height growth." U.S.F.S., Southern Forest Experiment Station, Forestry Note No. 81, 1952. Meagher, G. S. "Reaction of pinyon and juniper seedlings to artificial shade and supplemental watering." Journal of Forestry 41:480-482. 1943. Medin, D. E. "Physical site factors influencing annual production of true mountain mahogany, Cercocarpus montanus." Ecology 41:454-460. 1960. Merkle, John. "An analysis of a pinyon-j uniper community of Grand Canyon, Arizona." Ecology 33:375-384. 1952. Meyers, J. S. "Evaporation from the 17 Western States." Geological survey Professional Paper 272-D, U. S. Government Printing Office, Washington D.C., 1962. Millar, C. E. 1955. Soil Fertility. John Wiley & Sons Inc., New York, 436 pp . Myers, C. A. and J. L. Van Deusen. "Site index of ponderosa pine in the Black Hills from soil and topography." Journal of Forestry 58:548-555. 1960. Pawluk, Steve and H. F. Arneman. "Some Forest soil characteristics and their relationship of Jack Pine growth." Forest Science 7:160-173. 1961. Phillips, F. J. "Study of pinyon pine." Botany Gazette 48:216-223. 1909. Plummer, A. P. "Restoration of juniper-pinyon ranges in Utah.’ Proceedings Society of American Forester, Salt Lake City, Utah, 1958. Randier, Quincy. "Pinyon-j uniper in the Southwest." Trees — Yearbook of Agri- culture 1949. Reveal, J. L. "Single-leaf pinon and Utah Juniper woodlands of Western Nevada." Journal of Forestry 42:276-278. 1944. Shantz, H. L. Association of American Geology 8:81-107. 1923. Shirley, H. L. and Paul Zehngraff. "Height of Red Pine saplings as associa¬ ted with density." Ecology 23:370. 1942. 123 Shreve, F. "Conditions indirectly affecting vertical distribution on desert mountains." Ecology 3:269-274. 1922. Tarrant, R. F. 1949. "Douglas-fir site quality and soil fertility." Journal of Forestry 47:716-720. 1949. Tarrant, P. F. "A relation between topography and douglas-fir site quality. Journal of Forestry 48 10) : 733-734 . 1950. Tanner, V. M. "A biotic study of the Kaiparowits region of Utah." The Great Basin Naturalist 1:97-126. 1940. Turner, L. M. “'.elation of stand ensity to height growth." Journal of Forestry 41:766. 1943. Turner, L. M. "Some Profile charac eristics of the pine-growing soils of the Coastal Plain region of Arkansas." Arkansas Agriculture Experiment Station Bulletin 361, 52 pp . , 1938. Water Supply Forecast Unit and Office of State Climatologist, U. S. Weather Bureau, Salt Lake City, Utah. Isohyetal map of normal annual precipitation, 1931-1960 for the state of Arizona. Water Supply Forecast Unit and Office of State Climatologist, U. S. Weather Bureau, Salt Lake City, Utah. Isohyetal map of normal annual precipitation, 1931-1960 for the state of Utah. White, D. P. "Available water: The key to forest site evaluation." Fn First North American Forest Soils Conference Michigan State University, pp . 6-11, 1958. Wilde, S. A. "The Significance of soil texture, and its determination by a rapid field method." Journal of Forestry 33:503-508. 1935. Woodbury, A. M. "Biotic relationships of Zion Canyon, Utah, with special reference to succession." Ecol. Mono. 3:151-246. 1933. Woodin, H. E. and A. A. Lindsay. "Juniper-pinyon east of the Continental Divide, as analyzed by the line-strip method." Ecology 35:473-489. 1954. Youngberg, C. T. and H. F. Scholz, 1949. "Relation of soil fertility and rate of growth of mixed oak stands in a driftless area of southwestern Wiscon¬ sin." Soil Sci. Soc. Am. Proc. 14:331-332. Zahner, R. "Site-quality relationship in pine forests in Southern Arkansas and Northern Louisiana." Forest Science 4:162-176. 1958. Zinke, P. J. "Site quality for Douglas-fir and ponderosa pine in northeastern California as related to climate, topogrrnhy, and soil." Society of American Foresters Proceedings 1958:161-171. 1959. Zinke, P. J. "Site quality for Douglas-fir and ponderosa pine in northeastern California as related to climate, topography, and soil." Society of American Foresters Proceedings 1958:161-171. 1959. 124 6. WOODLAND TREE CHARACTERISTICS AND TREE CONTROL Robert J. Rivers 4 The purpose of this section Is to consider and evaluate the efficiency of tree control techniques from the standpoint of tree mortality and regrowth. Forage production relationships are discussed in another section of this study [Section 7 ] . The broad classes of pinyon-j uniper control are combustible, mechanical, and chemical. Tree-killing chemicals had not been employed on any of the sites visited. Mechanical techniques used on the study sites were cabling, single chain¬ ing, double chaining, and bull dozing. In chaining, two crawler tractors move through the trees with a long loop of cable or anchor chain stretched between them. Trees are caught in the loop and up-rooted. The weight of the chain is between 45-90 pounds per link, and the length is great enough to permit a 50-150 foot swath through the treatment area. Double chaining is the same as single chaining except that it is repeated twice in opposite directions. Cabling is the same as chaining except that a heavy mine cable (1"-1.75" diameter) is used in place of an anchor chain. Where per-acre tree stocking rates are low, bull¬ dozers are used to rip out individual trees. (Costs per tree are quite high( but kill results are very good.) Controlling pinyon-juniper lands by fire may be either accidental or inten¬ tional. Plots catalogued as "burned" included sites that initially may have been chained and later burned as well as several controlled burns and the site of one wild fire. The earliest control techniques were either hand chopping or individual tree burning [Hull and Doran, 1950]. It was not until 1951 that chaining or cabling 125 became a widely used control technique [Cotner, #210]. Information concerning pinyon-j uniper control and tree kill is fragmented, influenced by local practices , and not readily obtained. Most published research relies upon data of recent origin and may be briefly summarized as follows. Cost studies made by Cotner and Jameson do point out the influence of tree size on control costs [1963]. Several studies also indicate that it is basically impossible to obtain a reasonable kill by chaining or cabling trees whose heights are less than 10 feet [Arnold et_ al . , 1964]. Aro (formerly with U.S.G.S.), while evaluating control methods for the BLM, obtained significant correlation coeffi¬ cients when comparing kill percentage vs. percent of trees greater than 20 feet and also for percent of trees greater than 10 feet on projects that were single chained. He was unable to obtain the same degree of statistical reliability when he pooled his data for both single and double chaining [Aro, 1965]. However, aside from statistical difficulties, his data indicate that possibly the 10 foot height class is the break-off point as far as satisfactory kill percentage is concerned. Space occupied by pinyon-juniper and its relation to forage production is of prime concern to the range manager. It is now a generally accepted hypothesis that as crown canopy of the woodland species increases, understory forage produc¬ tion decreases [Arnold, ejt al . , 1964; Arnold and Schroeder, #18]. A significant portion of the effort of the personnel performing the present study was devoted to a test of this hypothesis. The results are reported in Section 7. The length of time for tree regrowth is also another unknown. It has been observed that residual trees missed by chaining or cabling do show a considerable increase in growth rate [Arnold, et al. , 1964; Aro, 1965]. However, what this rate means over the long run is still unknown. The only "longevity" study has been reported by Cotner who estimates that tree stands with an average age of 13 years and 52 years are producing only 94 percent and 29 percent respectively 126 of their potential forage production. He relied upon data supplied by Arnold, Jameson and Ried [1964], which in turn, came mainly from "invasion" situations. Whether the trees "released" following cabling would be the same size when i 52 years old is unknown. Similarly, except for Cotner's suggestion that tree seedling establishment occurs at the rate of five trees per acre per year in northern Arizona, little is known about this additional important variable [Cotner , 1963] . In more northernly sections of the study area it seems that the effect of heavy slash on forage production should be considered if mechanical control is used. Aro has noted that, of the sites he visited, control debris covered an area that varied from 10 percent to 50 percent, with the average being 25 percent [1965]. The adverse effects of excessive slash have also been mentioned by Arnold e t al . [1964]. (Slash remaining after bulldozing ordinarily is not a problem; similarly, if slash is winrowed, a much smaller land area is affected.) Basic Data — The data used in this section were collected from one hundred and sixteen (one tenth acre) plots located on pinyon-j uniper control projects throughout the five state area. Thirteen plots were deleted from the statis¬ tical analysis; nine which had been subject to more than one treatment and four which exhibited terain difficulties non-typical for the site area. Field Measurements — The following data were collected from each 10 x 43.6 plot: (a) diameter outside bark at 1 foot by species for all living and dead trees; (b) number of trees under one foot (1’) by species for living and dead trees; (c) trees were recorded as live (standing) or live (on ground); (d) estimate of slash cover;2 (e) whenever possible three (3) tree disks were _ _ _ _ _ _ cut lSo much fuel wood had been/ from some of the cablings (mainly BIA areas) that kill and slash percentages were difficult to estimate. 2This estimate was obtained by converting each pile of debris into the area of a rectangle. For single trees the slash cover was considered 75 percent of the rectangular area covered by the crown. For large piles of slash, the area covered was considered 100 percent of the rectangular area. also collected on each site. 1 6. a. Percentage Kill-Tree Diameter Correlation Investigation of the relationships between a measured tree characteristic and percentage kill took several forms. It was found that kill percentages associated with various control techniques bear little relation to basal areas, average diameters per acre, or total number of trees per acre. The most promis¬ ing approach requires that percent kill be related to percent of tree stand - 7 inches in diameter at 1 foot. This approach is not affected by differences between ecological provinces. The plot data were then analyzed statistically in the following model for a linear regression: log Y = log bo + b]_ log X , where Y = percentage kill X = percentage of stand ^ 7 inches diameter at 1 foot. Each control method was analyzed separately: chaining one way (54 plots); chaining two ways (22 plots) ; burning (18 plots) ; and cabling (9 plots) . ^ Analysis and Discussion — The results of machine analysis of the tree kill data are : 1. Chaining one way: log Y = log 6.18 + 0.6113 (log X) R2 = 0.898 2. Chaining two ways: log Y = log 16.5 + 0.4035 (log X) R2 = 0.924 3. Burned: Formula is not shown as R^ ; was only 0.276 ^-The collection area was not limited to the fixed plot. The criterion for selecting a disk was that it come from a live, standing tree, relatively free of stem damage. ) “Cabling observations were two few for statistical analysis. 128 Figure 6.a.l Kill and one way chaining IIT)I ssaj, 129 Percent of Stand Figure 6.a.2> Kill and two way chaining X X 03JX aSpquaoaaj 130 Percent of Stand Figure 6. a. 3. Kill and cabling 1 1 T>i 99^1 aSe^uaoaaj 131 Percent of Stand The results for sites which were burned indicated, as might be expected, that there is no consistent relationship between percentage kill and percent of stand - 7 inches in diameter. There was no statistical difference in tree kill percentages when the data were stratified by provinces. Figures 6.a.l and 6. a. 2 show the calculated curves for chaining one way and two ways. Figure 6. a. 3. is a suggested curve for cabling showing distribution of the nine (9) observations. The more comprehensive the control method, the greater the percent kill of the smaller diameter classes. At the extreme, burning, diameter relation¬ ships are of no significance. It must be concluded that it is possible to predict kill levels that can be achieved through chaining. For the present, cabling results remain tentative. Depending upon the homogeneity of the proposed site, a few or several one- tenth acre plots must be established to sample variations in stand diameter classes. The data collected on each plot should fulfill the requirements indicated by the following format. Table 6.a.l. Suggested form for collecting potential tree kill data Diameter at 1 foot 1 2 3 4 5 6 7 8 9 10 11 12 and etc. Number piny on _ Number juniper _ Sub-totals Number of trees less than 1 foot P inyon _ _ Juniper _ _ Sub-total _ Number of trees 2 7 inches in diameter _ _ Total number of trees _ Percent stand 2. 7 inches diameter The percent tree kill that any land manager is willing to accept should be 132 one of the prime criteria by which a stand is judged worthy of expenditures for tree control. The following table provides some appreciation of the range over which kill percentages will move. Table 6. a. 2. Percent of stand above 7" necessary to achieve a given kill level Control method Necessary percent of stand over 7 inches diameter @ 1 foot Chaining one way 30 percent 60 percent 85 percent Chaining two ways 15 percent 45 percent 78 percent Cabling 52 percent 85 percent 100 percent Acceptable percent tree kill 50 percent 75 percent 95 percent These data are generally applicable to current management trends and, once the broad policy decision of the minimum acceptable level of tree kill has been determined, it should be possible to examine each proposed tree control site in the manner suggested. Recommendation for future studies — It would be useful to collect additional ob¬ servations (particularly with respect to cabling experience) ; regression equations could be developed and improved as necessary. 6.b. Direct Growth Responses Data collected from live residual trees were analyzed to test the relation¬ ships between sizes and species. Accordingly, the diameter at 1 foot of all living trees on 103 eradication plots, excluding the burned sites, were analyzed to determine means and variances. In addition to the above, disks were collected from 173 trees on 60 of the above mentioned plots in an attempt to determine if any relationship existed 133 between tree diameters and growth increments following conversion. Unfortunately, it was too time consuming to collect an adequate number of "control" discs in woodland stands adjacent to each plot. Only some generalized conclusions can be drawn. Analysis and Discussion — It is unlikely that pinyon pine under 3 inches in dia¬ meter will be knocked down by chaining or cabling. Trees in the 3-5 inch diameter class will be knocked down, but they may not die. Junipers smaller than 3 inches in diameter will probably remain erect. Those in the 6-9 inch diameter classes will be knocked down but not necessarily killed. These are some of the conclusions suggested by the data in Table 6.b.l. The major difference between species was in terms of trees left alive on the ground. Pinyon appeared to be more susceptible to mortality after having been pushed over. This trait may be due to differences in root syBt^ms, and relative inability to recover from stem injuries inflicted by the conversion apparatus. Juniper trees appear to be quite tenacious and unless the root sys¬ tem is severely (not just partially) injured, they may be expected to survive (even those in the 6-9 inch diameter classes) . A live tree on the ground probably affects the site just as much as a live standing tree does. Table 6.b.l. Diameter characteristics — residual trees (85 plots) Standing trees Downed trees Species Total No. Live % Live Mean dia¬ meter Vari¬ ance Total No. Live % Live Mean Dia¬ meter Vari¬ ance Pinyon 170 156 92 1.9" +1.17 77 18 24 3.1 +2.34 Juniper 229 208 91 2.3" +1.24 329 105 32 5.9 +2.98 This summary of residual tree data demonstrates the importance of selecting the 7-inch diameter class as the criterion upon which to base estimates 6f tree kill. 134 Table 6.b.2 summarizes the results of an attempt to relate tree "release" and subsequent growth rates to actual conversion dates. Data from 60 conver¬ sion sites were stratified in such a manner as to show the number of maximum growing seasons since the time of conversion. The diameter classes are the estimated diameter class (D.O.B.) of individual trees at the time of conver¬ sion. On each disc the number of rings exhibiting a marked increase in growth rates was determined by a student who had no knowledge of conversion site histories . Despite what often appear to be obvious evidences of "release" in the growth rings of many discs, the present analysis indicates that there is no significant difference in percent response between species or even between the diameter classes.'*" The most significant result is that the major portion of instances of apparent response took place at the beginning of the fifth grow¬ ing season following control. Only 27 percent of the sample showed response attributed to the control technique before the fifth year following control. After the fifth post-eradication growing season, the incidence of apparent response was 79 percent. Choice of any year following the fifth produced nearly the same result. Figure 6.b.l is a picture of a disc taken from a Juniperus osteosperma on the Navajo Indian Reservation in Arizona. The site was converted in 1957; the disc was collected in September 1965, or 9 growing seasons later. Obvi¬ ously, not all discs exhibited as much apparent "release." Recommendations for future studies — Set up permanent study plots on the older conversion sites and determine how long growth response will last. 6.c. Conversion Site "Longevity" Since few definite conclusions about direct growth response of residual can ^Nevertheless , it is believed that additional observations, coupled with "control" discs, would produce positive results. 135 Table 6.b.2. 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'd- m m p> 00 Ht 00 m CO D CO U t-4 5“ •H C 8 O D D }m 4-> 4J O CO 4J c H /~s Ov LO o Sm c o o }-l D > o o XJ CO CO rH CO s-s 00 CD 00 CO u o <4-1 D 00 4-1 O D 4-> o >M a. o vO x: CO D V4 d oo •r4 Pm O CO 4-) e M VO U-\ ov O S-l 4-» C o o CO •rH •H C M }M D > O O X co cO r— i CO *5 00 CM 161 REFERENCES 1 il) Aro, Richard S, Conversion of Pinyon— Juniper Woodland to Grassland. Water Resources Division, U. S, Geological Survey. Denver, Colorado. (Unpublished, preliminary draft) Summer, 1965, 123 pp. Arnold, J. F. and W, L. Schroeder. Juniper Control Increases Forage Production on the Fort Apache Indian Reservation. Rocky Mountain Forest and Range Experiment Station, Station Paper No. 18. — - - _, Donald A. Jameson, and E. E, Ried. The Pinyon-Juniper type of Arizona, Effects of Grazing, Fire and Tree Control. Production Research Report No. 84. U.S.D.A., Sept. 1964, 28 pp. Corner, M. L. Controlling Pinyon-Juniper on Southwestern Rangelands. Arizona Agricultural Experiment Station Report 210. 28 pp . Corner, M. L. Optimum Timing of Long-term Resource Improvements. Journal of Farm Econ. 45(4), Nov. 1963, p. 732. Hull, A. C, and C. W. Doran. Preliminary Guide to Reseeding Pinyon-Juniper Lands of Western Colorado. Rocky Mountain Forest and Range Experiment Station, Station Paper No. 4. 1950. Parker, K, W. Juniper Comes to Grasslands. American Cattle Producers. November 1945, pp. 12-14. " 162 7. RANGE EVALUATION OF PINY ON- JUNIPER CONVERSIONS Grazing by domestic livestock and wildlife has been the most important use made of the pinyon-j uniper type; a primary question, therefore, is how to improve grazing conditions. All intelligent decisions about the worth of converting woodlands stands to grass require evaluation of understory pro¬ duction potentials. Given the wide climatic and edaphic variation in the five state area, inadequate knowledge of grazing histories, and a near absence of sites that express site potentials, range managers are apt to conclude that it is unusu¬ ally difficult to predict future benefits from grazing management alone. However, one relationship stands out throughout the woodland type: understory production (especially grass production) is inversely proportional to an increase in percent of tree canopy. A production-canopy curve based upon grass production on the sites having the highest range condition at various canopy levels facilitates estimates of grass yield potentials achievable through management of particular tree stands. Since current understory pro¬ duction and percent of tree canopy are readily ascertained, it is a straight¬ forward task to make comparisons with potential yields. If the potentials are great enough, it may be decided that tree control is unnecessary. Greatest increases in grass production following control will be obtained where trees are thickest, for such woodland stands have relatively the least amounts of existing forage, regardless of management. Arnold e_t al_. [1964] substantiate the inverse relationship between per¬ cent of tree canopy and forage yield. In northern and central Arizona, air dry weights of understory grasses and forbs vary from 620 pounds herbage per 163 acre, where there's an absence of canopy intercepts, to 40 and 65 percent less with 10 and 30 percent canopy intercepts. On transects with a 50 percent inter cept, the herbage yield of grasses and forbs was 82 percent less than yields free of tree influence. Using data from the Apache reservation, Arnold and Shroeder [1955] found that the relationship of herbage yields to the number of trees per acre took the same inverse form. Air dry herbage under little or no tree cover was approximately 600-700 pounds per acre, but leveled off below 100 pounds when densities reached 400-500 trees per acre. An individual tree influences both herbage production in pounds of forage and composition of species far beyond its canopy. Arnold [1964] measured this influence from a 19 foot juniper tree and found a sizable area immediately beyond the competition of roothairs from the long laterial roots. As the micro climate changes with distance from the tree stem, there is a change in species composition. More tree rootlets grow in the openings than directly under tree crowns.. They may literally fill the surface soil in the openings of fairly dense stands of trees [Plummer, 1958], 7. a. Herbage Production - Percent Tree Canopy Relationships — H. E. Isaacson Figures 7.a.l, 7. a. 2, and 7. a. 3 show the relationship of maximum grass production to percent canopy of pinyon and juniper by ecological province, Escalante-Sevier , La Sal, and Coronado. Site data used for these curves are those reflecting the highest range conditions observed in each province. The situations depicted should not be confused with ultimate potential of a site, for these curves do not reflect conditions that may be found in relict areas. 7 . b . Bunch Grass — Short Grass: Relationship to Tree Cover — H. E. Isaacson Short grasses such as blue grama and galleta grass were never observed growing in the litter directly beneath trees (Figure 7.b.l). Blue grama, Bouteloua gracilis , seems to be particularly affected by 164 Air dry forage production Air dry forage production 900 " 165 Figure 7 . b . 1 . Native shortgrass is never found directly under trees. 166 shading [Johnson, 1962] and is seldom found under plants with dense canopies. Some grasses, such as mutton grass, Poa fendleriana, (a bunch grass) are often found only under trees. Indeed, the present study confirms the notion 4 that jji general bunch grasses are less influenced by tree canopy than are short (sod-forming) grasses. Figures 7.b.2 and 7.b.3 show squirrel tail, Sitanian hystrix, and Sandberg bluegrass, Poa secunda, growing in 4 and 2 inches of litter respectively on a Nevada site. While it is true that indi¬ vidual plants lack vigor where influenced by shade or tree roots, they still maintain themselves. Thus, only beyond the tree laterial root zone, in open stands, are plants vigorous. However, take away the influence of a live, competitive tree, and leaf litter provides an excellent site for bunchgrass. Figure 7.b.4 shows excellent grass cover and vigor under a dead pinyon. In the Escalante-Sevier province the species are mainly bunchgrasses . Grass production is seldom very heavy because major grass species left are squirrel tail, Sitanian hystrix, and Sandberg bluegrass, Poa secunda, neither of which attains much stature. Bluebunch wheatgrass and Idaho fescue, higher producers, are often only a remnant in the composition. Canopies of 20 to 50 percent (Figure 7.a.l) appear to set the range of consideration for maximum increased production following eradication treatment. Bunch grass species are also more prominent in the La Sal province, but generally production is higher than in the Escalante-Sevier province. The reason is probably a combination of more favorable precipitation distribution (early spring and mid-summer high periods) and grass species found in the woodland type. Major species in the La Sal province are fairly high producing bunchgrasses and consist of: bluebunch wheatgrass, Agropyron spicatum, beard¬ less wheat grass, Agropyron inerme, Indian ricegrass, Oryzopsis hymenaides, and mutton grass, Poa fendleriana. Canopies of 30 to 60 percent appear to be the range where greatest 167 Figure 7.b.2. Squirreltail growing in 4 inches of litter on a Nevada pinyon- juniper site. Figure 7.b.3. Sandberg bluegrass growing in 2 inches of litter on a Nevada pinyon- juniper site. Figure 7.b.4. Native bunchgrass looks vigorous growing in litter under a dead pinyon. 168 increases in production can be obtained through some form of eradication treatment of the trees (Figure 7. a. 2). The most outstanding characteristic of the Coronado province in terms of understory growth is the universal cover of grass, especially blue grama (Boutelava gracilis) . Even when abused, sites sustain fairly good grass den¬ sity and total grass production is high. However, the leaves of the plants seldom grow very tall so usable forage for livestock is reduced, even granting high density. Maximum improvement through manipulation of the site appears to be in canopies from 30 to 50 percent (Figure 7. a. 3). Discussion — Apparently within the true pinyon-j uniper woodland, understory vegetative production was never very heavy. Even where protected from live¬ stock grazing, plants are not robust where they compete with the trees. Once canopy percentages get in the neighborhood of 25 percent, most of the area between trees must be affected by tree roots or canopy shade. Plants facing this type of competition will deteriorate rapidly from a combination of climatic stress, grazing, and ever increasing tree competition. Once the understory resource has been depleted, improvements through grazing management practices will probably be imperceptive . Only in open stands were tree com¬ petition is low and understory seed stock still present, will response to management be visible in the short run. 7.c. Variation in Grass Production Associated with Conversion Methods — H. E. Isaacson This portion of the study provides site qualification measurements that will aid in selecting woodland sites that have the potential for successful conversion to grass. Tree removal treatments varied greatly; they ran the gamut of dozing 169 individual trees to chaining trees with heavy anchor chains and windrowing slash with bulldozers. Grass planting techniques were confined to broadcasting seed before or after tree removal or drilling seed on cleared areas. To sim¬ plify measuring production benefits from treatments and to provide a suitable sample size, all combinations were categorized into three major site manipula¬ tion practices: 1. Remove tree competition only0 2. Broadcast introduced grass seed and remove tree competition. 3. Chain or cable trees, windrow slash and drill introduced grass seed. Removing Tree Competition Only — This treatment shows less dramatic change than the other two treatments. All mechanical tree killing practices are included in the sample (bulldozing, cabling either once or twice and chaining once or twice) . The bulldozing technique was used mainly on the so-called tree invasion sites and resulting tree kill was high, only seedlings were missed. Chaining either single or double killed most trees with a stem diameter of 3 inches or larger at one foot height. Trees from 3 to 5 inches diameter may survive cabling. As slash builds up from greater tree stand densities, kill of younger trees drops off. Pulling trees over will have a long-term influence only if the tree kill is high. Old, fairly even-aged stands will be best for cabling or chaining. Any stand with a lot of saplings requires additional treatment for lasting benefits. Percent kill was high enough on projects visited so that production potentials were probably not affected by the remaining live trees. The rate of increase in native herbage yields following juniper control treatments in Arizona was indicated through chronological evaluation made by Arnold and Schroeder [1955], Areas that had been cleared for two growing seasons produced an average of 82 pounds of herbage per acre more than areas 170 cleared for one growing season. After eight seasons, the average increase in herbage yield tapered off at a total production level of about 650 to 700 air-dry pounds per acre. Arnold _et_ al. [1964] conclude that maximum production following tree removal occurs 5 to 10 years after control and maximum production in northern Arizona can be expected at around 700 pounds air-dry herbage per acre. Tree control without reseeding was not used extensively in the Escalante- Sevier and La Sal provinces. Where employed the highest increases in native ti grass production were observed from bunchgrass understory but generally results were eratic. Certain tremendous increases, from 150 pounds of air-dry grass to 850 pounds, occurred where there was an excellent stand of good native grass species (Indian ricegrass, bluebunch wheatgrass, or Mutton grass) under the trees. Combinations of these species common to their provinces made up 40 to 50 percent of the understory composition and were uniformly distributed throughout the woodland stand. The number of observations of this practice in provinces 1 and 2 were too few to allow data analysis. Tables 7.C.1, 7.C.4, and 7.C.7 show whether or not the treatment produced a significant increase in grass production and basal area for each province. Tree control only is by far the most common treatment in the Coronado province. There are many more projects of this type than the 40 that were visited . Broadcasting Grass Seed and Removing Tree Competition — When proper sites are selected, this combination of treatment and reseeding is very effective. Grouped here are projects cabled or chained (single or double) before or after grass seed broadcasting, (generally from aircraft). Evaluation of seeding results is not as simple as in the case of the other two major combinations. Introduced grass establishment is seldom uniform due to the presence of slash. 171 lack of uniformity of seed distribution and competition of native plants. Plots were located to reflect average conditions on as uniform areas as possi¬ ble. The grass species planted was mainly crested wheatgrass; projects where other species were planted are footnoted in the tables and figures. In both the Escalante-Sevier and Coronado provinces this treatment did not consistently show a significant increase in seeded species production over the native production on the comparison site, so there were too few observations for each of these provinces to allow statistical analysis. Tables 7.C.2, 7.C.5, and 7.C.8 show if significant increases in grass production and basal area fol¬ lowed this type of treatment in each province. The high degree of success from broadcast seeding in the La Sal province is of great interest, particularly since the treatmen| is much less expensive than windrowing slash before drilling grass seed. Cham or Cable Trees, Windrow Slash and Drill Grass Seed-- This is the ultimate seeding practice in the pmyon-j uniper type; every project visited with this treatment was a success. There is greater latitude in site choices if this treatment is used. Grass production on a given site is more uniform and usable surface area also is greater. Knowledge of important site factors renders results from this type project fairly predictable. Each site reflects a dif¬ ferent environmental complex with different productive potential. Eckert et al . [ i 9 6 1 j measured responses of Agropyron cnstatum and Agropyron desertorum at three different sites in eastern Nevada and found grass production was consis¬ tently different over a period of 17 years. Soil profile characteristics and slope appeared to explain a great deal of the variation in grass production. Greatest production was found on a deep profile with a low gravel content receiving additional moisture from runoff of steeper slopes. 172 In the southwest, Reynolds and Springfield [1953] observed potential production of crested wheatgrass herbage varied widely with growing condi¬ tions, mainly with differences in precipitation. On 11 sites in three vege- ( tative types, Ponderosa pine, big sagebrush, and pinyon-j uniper , air-dry herbage production increased as precipitation increased within the same vege¬ tative type. However, a precipitation range of 14 to 17 inches in the sage¬ brush type produced as much herbage as 17 to 24 inches in the Ponderosa pine type. Production in the pinyon-j uniper type in 1949 wps as follows: Air-dry Location Elevation Precipitation Herbage Production Glorieta Mesa, N. M. 7,380 f t . 16 in . Dog Knobs, Arizona 6,400 ft • 15 in „ Corona, N. M. 6,670 l-h ft • 15 in» 800 lbs/acre 640 lbs/acre 520 lbs/acre Production in the pinyon-j uniper type was much lower than the other types. Too few seeded projects of this nature were available in the La Sal and Coronado provinces to develop an analysis of how site factors contribute to resulting grass production. Where observed in the La Sal province, the technique was always successful, and resulting grass production was signifi¬ cantly greater than broadcasting seed when the two practices were carried out on the same site (Table 7.C.10). Seeding grass species, especially introduced species, requires a unique site in the Coronado province, even if drilled. Total average annual preci¬ pitation requirements appear to be 15 inches or higher on sites that receive fairly heavy late winter precipitation [Springfield, 1965] . Results from this treatment (Tables 7.C.3, 7.C.6, and 7.C.9) from all the provinces were tested to see if the treatment produced a significant increase in grass production and glass basal area. 173 X 03 X 0) o 34 DU 34 03 •H O 0) C/3 I CU 4-1 d cd * - i 03 a 03 W CU X X d °i— I 03 X a 4 •K “K u 03 03 ■3C ■fc •K ■X X (U ON X 00 03 34 • 9 • • 03 03 ON X CO 34 X d P X d • 9 03 U -K J/ X X » — 1 ’ — 1 X O 03 < — i u — / 03 34 i — 1 O 0) 34 03 9 X 03 r'- X X X 03 rH d a) • » e • 34 o o 34 rH o o -C3" X 34 a 03 X 03 d 03 > o X ■X o X X G’x cu 03 6 B Mi 34 d o o X a 03 r-^ O 34 34 03 X X X X X • *X d 03 • °rl X — 1 T— 1 X 4-3 X 03 03 I— 1 £ t — i > > P CU 03 03 1 — 1 ’ — 1 X 03 CU X 03 34 * — 1 m 4-1 iD X X X o o o3 03 03 03 03 X • • CU s — l —4 1 — 1 i — 1 X o o S-i °rl x £ 03 03 X X X X X X 03 o X X 4C a 03 o3 d ■X °r4 03 03 X 03 -K £ a C3 a) d d B 03 X d d d o o 4-1 3-4 o O 34 rX °H 03 X p X X cu <4-4 03 d d X u a 3-1 X r—l -i—i •rl p P H 7”H X 03 03 03 X X o3 X X o3 o o CJ a CJ > 34 34 ex ex X 03 03 03 X 03 03 X 03 0) X 34 34 03 « • • 03 X X 03 a X 03 X X 54 4-1 X X X °r4 03 a) 03 CJ s S 03 > > CU 34 o o •X °r4 6 ’rl d 03 o 03 o X X X o3 44 03 CJ CJ 03 d 03 o5 z X X P x X "rl x d d GO GO f— I X o d o3 U »pt P 4-1 CO C/3 C/3 ■K -X 4C ■K * 03 cu 34 03 174 X) P £ co 0) •H a cu a CO x CL) a p x o p x p •H £ p CO £ a x P O P X P P P £ p P X p 03 CJ co W P o •p p a P x o p PH CO CO 03 P 00 X a) p 03 QJ P H S'? o O 1 — 1 4< 4c p P 03 03 4< •K 4C p P CO QJ rH X \ — 1 o CN X CN c P 03 P • • • • • • • • o 9 o o CQ 03 CO t — 1 St rH CN o CN r— 1 o CJ o cu a o p p c o x > 03 4< 4< t •a •H 4< 4< 4< 4< ■a P CO CN CN CN 00 CN CT\ cD o CT\ CTs cfl r-P X 00 co I-" r-» st CO rH X H CN St 1 - 1 6s? 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Site data from 28 chaining, windrowing, and drilling projects in the Escalante-Sevier province, 36 broadcast and chain projects in the La Sal province, and 39 cabling or chaining only projects in the Coronado Province were used. The dependent and jr independent variables for the three regressions are shown in Table 7.d,i. An explanat ional listing of these variables is found at the end of this section (Table 7 . d . 6) . The cross-sectional data employed in the regression analysis almost cer¬ tainly exhibits multicolinearity; observations of individual variables are not truly independent. It is possible to attempt to allow for interactions among variables by combining them in different fashions (indeed linear combinations have been employed extensively in the present instance: X2*Xg, X^'X^q, etc.). Such combinations may lead to improvements in calculated coefficients of determination, but the interaction terms themselves become difficult to inter¬ pret and explain. The interaction terms actually employed are those thought to have the strongest effect on the dependent variable in question. Choices were based on the methods employed by Hurst and Pederson [1964]. The exact interrela¬ tionships that each choice implies have not been worked out, and no inter¬ pretation will be given in this particular report. The machine program computed regression coefficients, mean squares, 2 error terms, and r s for all of the variables (as listed in Table 7.d.l) for each separate province. The variable explaining the least amount of variance was then automatically dropped and the computations were repeated. 189 Table 7.d.l. Dependent and independent variables used in multiple regres- sions by province Dependent variables Dependent variables used by province Escalante- Sevier La Sal Coronado *1 Production seeded grass (drilled) X Y2 Production seeded grass (broadcast) X Y3 Production native grass X Independent variables Independent variables used by province Escalante- La Sal Coronado Sevier *1 Average annual precipitation Only used in interaction x2 Depth A layer Only used in interaction x3 Depth A and B layer X X X X4 Texture A horizon X X X X5 Development of B horizon X X X x6 Latitude X X X x7 Stoniness A horizon X X X x8 Sternness surface X X X x9 Pinyon site index X X X x10 Juniper site index X X X X11 Precipitation x depth A X X X x12 Precipitation x latitude X X X x13 Precipitation x stoniness A X X X x14 Precipitation x stoniness surface X X X x15 Precipitation x pinyon site index X X X x16 Precipitation x juniper site index X X X x17 Depth A3 x stoniness surface X X X x18 Depth A3 x juniper site index X X X x19 Development B x pinyon site index X X X Xo o Development B x juniper site index X X X X21 Pinyon site index x juniper site index X X X x22 Native grass production prior to treatment X X x23 Native grass production prior to treatment^ X X x24 Precipitation x grass production prior X X x25 Latitude x grass production prior X X x26 Pinyon site index x grass production prior X X x27 Latitude x grass production prior X X TOTALS 19 25 25 190 The program continued in this "step-wise" fashion until only one independent variable remained. At each "step" the coefficient of determination of the model fell until, the final, residual variable was ordinarly shown to explain 4 10-20 percent of the total variation in Y (grass production) . Table 7.d.2a. Partial correlations of residual variables with seeded grass production in the Escalante-Sevier province and drill) (chain, windrow, Residual variables R X3 Depth A + B horizon .627 X21 Pinyon ht. x pinyon site index .301 x5 Development of B horizon .047 Xl9 Development of B horizon x pinyon site index .234 x15 Precipitation x pinyon site index .315 x8 Stoniness of surface .005 X9 Pinyon site index .193 X16 Precipitation x juniper site index .657 X14 Precipitation x stoniness of surface .072 By scanning the output data in reverse order, it was possible to choose the particular regression model with the fewest number of independent vari¬ ables consistent with some desired r^ value. Or, to put it another way, all the variables which seemed to make the least contribution to the estimating equation could be dropped out. Residual variables which remained in the step-wise program the longest are displayed for each control practice and appropriate province in Table 7.d.2 (a, b, and c) . 191 L C1 1 J 1 e /.d.zb. Partial correlation of residual variables with seeded grass - - production in the La Sal province (broadcast and chain) Residual variables t> X£6 Pinyon site class x grass production prior to .737 treatment X15 Precipitation x pinyon site index -.052 X22 Grass production prior to treatment -.062 x16 Precipitation x juniper site index .449 X21 Pinyon site index x juniper site index -.047 Xg Stoniness of surface 394 X17 Depth A horizon x stoniness surface -.052 X 3 q Juniper site index 059 i able /,d,2c. Partial correlation of residual variables with native grass . . -■ production in the Coronado province (chain or cable only) Residual variables x26 Pinyon site index x grass production prior to treatment .651 X13 Precipitation x stoniness surface .506 x24 Precipitation x grass production prior to treatment .624 x6 Latitude -.367 X7 Stoniness A horizon .503 x8 Stoniness of surface .423 X14 Precipitation x stoniness of surface .421 192 Table 7.d.3a. Residual variables and regression coefficients for selected control practices - Escalante-Sevier (chain, windrow, and drill) Variable Regression coefficient X3 Depth A and B horizon 1094.4752** X2i Pinyon sites ht. x juniper site index - 28.2317** x5 Development of B horizon +2260.4283** X19 Development of B x pinyon site index - 112.5741** x15 Precipitation x pinyon site index + 28.8118** x8 Stoniness surface - 300.2593* x9 Pinyon site index + 553.6036** x16 Precipitation x juniper site index + 41.8800** X14 Precipitation x stoniness surface + 21.3885* Table 7.d.3b. Residual variables and regression coefficients for selected control practices - La Sal (broadcast and chain) Variable Regression coefficient X20 Pinyon site index x grass production prior Precipitation x pinyon site index X22 Grass production prior X^£ Precipitation x juniper site index X21 Pinyon site index x juniper site index Xg Stoniness surface X^7 Depth x stoniness surface X-^q Juniper site index + 1.2806** +12.1509** -32.5088** - 6 , 7530ns -12.1740** -63,4908** + 7.5444** +421.6531* Table 7.d.3c. Residual variables and regression coefficients for selected control practices - Coronado (chain and cabled) Variable Regression coefficient x26 Pinyon site index x grass-production prior + 0.1299** X13 Precipitation x stoniness A - 2.4041** x24 Precipitation x grass production prior - 0.1167** x6 Latitude - 6.8787** x7 Stoniness A horizon +41.7481** Xg Stoniness surface -72.5863** X14 Precipitation x stoniness surface + 4.7158** **Signif leant at 0.05 *Signif leant at 0,01 level . level . 193 Table 7,d,4. Estimating equations for forage response E seal ant e-Sevier Chain, windrow, drill La Sal Broadcast and chain Coronado Chain only Y]_ and Y2 are Yl = 2978.70 - 1094.48 X3 - 28.23 X21 .861 .742 + 2260.43 X5 - 112.57 X19 + 28.81 X15 - 300.26 Xg 4- 553.60 X9 + 41.88 X16 + 21.39 X14 Y2 = 3949.81 + 1.28 X26 + 12.15 X15 .885 .783 - 32.51 X22 - 6.75 X16 - 12.17 X2l - 63.49 X8 + 7.54 X17 + 421.65 X1Q Y3 = 240.86 + 0.13 X26 - 2.40 X13 .904 .816 - 0.19 X24 - 6.88 X6 + 41.75 Xy - 72.59 X8 + 4.72 Xu seeded grass production and Y3 is native grass production. 194 Results — With all original variables included [Table 7.d.l], the coefficient of determination for each model was greater than 0.90. Models containing only the residual variables have rz ' s of approximately 0.74, 0.78, and 0.82 i for each practice, respectively. Table 7.d.3 (a, b, and c) contains these coefficients along with the results of F tests on B values. Except for one instance, all of these regression coefficients were significant at the 0.01 or 0.05 levels. Estimating equations are in Table 7.d.4. In some instances the algebraic signs of the regression coefficients are r the reverse of what might otherwise be expected. These signs may be com¬ pared with those of the simple correlation coefficients shown in Table 7.d.2 (a, b, and c) , which, by and large, have the signs that would be thought nor¬ mal. The "reversed" signs in the estimating equations simply prove that interaction between the ’ s in question and at least one other variable is so great that the expected sign is "swamped out." Conclusion — These estimating equations are based on collection of only one year's data. They should be used with caution. As an experiment, the site factors associated with a number of 1964 grass production observations were introduced into the appropriate estimating equations. The 1964 data were taken from control projects also visited in 1965. The expected production, A Y, was compared with actual production in a Chi square test (even though the sample sizes were small: 3 to 6 degrees of freedom). An example of the results is shown in Table 7.d.5. Only Escalante-Sevier data need be shown. The null hypothesis is that there is no significant difference between actual and expected production within the same province when utilizing the O same tree control method. But since any x above 16.0 (with 3 degrees of freedom) means that there is virtually a 100 percent chance that the sam¬ ple of actual observations did not come from the expected population, the 195 hypothesis would be rejected. On purely statistical grounds it would be rejected with respect to the results obtained using 1964 La Sal and Coronado data as well. Part of the difficulty inherent in the application of the developed esti- mating equations is tied to site Table 7,d.5o Chi-square test of ine 1964 data factor interactions. But more important is Escalante-Sevier estimating equation employ' Study Grass production (lbs acre) 1 2 (2-1) 2 number Expected Actual 1 176 577 527 4.33 171 1323 341 728.9 173 232 118 56.0 182 770 811 2.28 X2 = 791.4 that cross-sectional data do not capture the great annual fluctuations in forage prouction„ What is needed are time series data from a variety of projects. Then the estimating equations could be linked to an average of several year's production figures. Nonetheless, it is possible to learn a good deal about conversion alter¬ natives from an analysis of the quantity of cross-sectional data accumulated during the course of the present study. Section 8 of this report has been developed to provide recommendations concerning the role of individual site factors for enhancing success in seeding and conversion projects. These recommendations should prove especially useful in the selection of eradica¬ tion and seeding sites. 7.e. How Tree Removal Affects the Amount of Usable Acreage — H. E. Isaacson All three of the basic tree removal treatments considered take portions 196 of the conversion project completely of production because of downed tree material. Treatments that do not involve piling or windrowing downed material also restrict utilization of forage by livestock because of coverage by dead tree crowns. This is not a permanent loss; the tree crown deterioration process allows most of this forage to become available in about 5 years where there is pressure from cattle, but the time process may be extended with light use or with smaller livestock. On seeding projects where downed trees were windrowed, a rough measure- i ment of several portions of these projects was made to determine the amount of area taken up by piled debris. Windrowing causes 3-10 percent of the area to be nonproductive. If these piles are burned, the bare strips will probably fill in with some form of vegetation; however, it will take consider¬ able time for grass to be dominant. A higher percentage of nonproductive or unavailable area is generally associated with projects that are not windrowed. An estimate was made in each of the 9.6 square foot grass production plots of the percentage of the area in the plot that heavy debris made unproductive or unavailable to large grazing animals. These estimates were averaged for each project and it was found that the percent of unusable acreage ranges from approximately 5 to 35 percent. In order to provide a guide for unusability predictions where no windrow¬ ing is planned, the tree canopy percentages of the adjacent woodland stands were plotted against unusability on various projects. For the first five years following conversion, unusable acreage will be at the rate of 9.3* (% crown canopy per acre) and thereafter at the rate of 0.7«(% crown canopy per acre) . 197 Table 7.d.6. Listing of regression variables used singly or in combination X-^ Precipitation in inches X£ Depth of A horizon in inches X3 Depth of the A and B horizon in inches X4 Texture of the A horizon, valued as follows: 1. Loamy-sand to sand 2. Silty-clay to clay 3. Sandy-loam 4. Sandy-clay, silty-clay loam and clay-loam 5. Sandy-clay, silty-loam, silt and loam X5 Development of the B horizon, valued as follows: 1. Well developed layer 2. Well defined B-^ or B^ layer 3. Poorly developed B or Bo layer 4. Possesses some B horizon properties (A3 or Ac horizon) 5. Little or no evidence of B horizon X^ Latitude - The numbering system initiated at the extreme south end of the province and increased one for each 10' in latitude. Example: 37° 00' = 1; 73" 10' = 2, etc. Xy Stoniness in the A horizon in percent Xg Stoniness on the surface in percent area covered X9 Pinyon site index - This is the height of trees with a 10 inch stem dia¬ meter measured one foot from the ground and is given in feet. X^Q Juniper site index - This is the height of trees with a 10 inch stem diameter measured one foot from the ground and is given in inches and feet . X22 This is an estimate of air-dry grass production per acre in pounds per acre on the project area prior to treatment. This was taken from the untreated area adjacent to projects 198 REFERENCES Arnold, J. F. 1964. "Zonation of understory vegetation around a juniper tree." Journal of Range Management 17"(1) : 41-42 . Arnold, J. F. , D. A. Jameson, and E, H„ Reid. 1964. "The pinyon-j uniper type of Arizona: Effects of grazing, fire, and tree control," U.S ,D.A Forest Service Production Research Report No. 84, p. 28. Arnold, J. F. and W. L. Schroeder. 1955. "Juniper control increases forage production on the Fort Apache Indian reservation," Rocky Mountain Forest and Range Experiment Station Paper, U. S. Forest Service Paper No. 18, p. 35. Eckert, R. E. Jr., A. T. Bleak, J. H. Robertson, and E. A. Naphan. 1961. "Response of Agropyron cris tatum, A. desertorum, and other range grasses to three different sites in eastern Nevada." Ecology 42 (4) : 775- 782 . Frischrecht, Neil C. and A. Perry Plummer. 1949. "A simplified technique for determining herbage production on range and pasture land." Agron, J ournal 41(2) :63-65. Huret, R. L. and M. W. Pedersen. 1964. "Alfalfa seed reductions or a func¬ tion of genetic and environmental characteristics." Advancing Frontiers of Plant Science, Vol. 8, 41-54. Iorns, W. V. , C. H. Hembree, D. A. Phoenix, and G. L. Oakland. 1964. "Water resources of the upper Colorado river basin — 'basic data." Plate Volume, U.S.G.S. Professional Paper 442. Johnsen, T. N. , Jr. 1962. "One-seeded juniper invasion of northern Arizona grasslands." Ecology Monographs 32:187-207. Pechanec, J. F. and G. D. Pickford. 1937, "A weight estimate method for the determination of range or pasture production." Journal Am. Soc, of Agron. 29(11) 894-904. Plummer, A. P. 1958. "Restoration of j uniper-pinyon ranges in Utah," Pro¬ ceedings of American Foresters, Salt Lake City, Utah, Reynolds, H. G. and H. W. Springfield. 1953. "Reseeding southwestern range lands with crested wheatgrass." U.S.D.A. Farmers Bulletin No. 2056, p. 20, Springfield, H~ W. 1965. "Adaptability of forage species for pinyon~j uniper sites in New Mexico." Rocky Mountain Forest and Range Experiment Station, U, S, Forest Service Research Note R.M.-57. Water Supply Forecast Unit and Office of State Climatologist, Bureau, Salt. Lake City, Utah. Isohyetal map of Normal Annual 1931-1960 for the state of Utah. U. S. Weather Precipitation , Water Supply Forecast Unit and Office of State Climatologist, Bureau, Salt Lake City, Utah. Isohyetal map of Normal Annual 1931-1960 for the state of Arizona, U. S, Weather Precipitation , 199 8, CONVERSION DECISION i RECOMMENDATIONS Except for special cases, the best current use of pinyon- juniper lands in the Great Basin and Colorado Plateau is to provide forage for grazing animals. Rehabilitation programs will be based upon potential of an individual site to respond to either livestock control as a means of improving range health or tree eradication to increase forage production, A decision to manipulate the cover t type must be based on sound ecological principles. This section provides guidance for making alternative management decisions. If eradication of a woodland stand is contemplated, consideration should be given to the site qualifications nec= essary to promote success and the technique combinations applicable to the chosen area , 8. a. General Considerations When Choosing Conversion Sites -- E„ Eber hard , R, J, Rivers, and H„ E, Isaacson A general requirement is to restrict choices to areas of uniform site condi¬ tions with slopes less than 15 percent. On Individual sites it is necessary to determine average percent tree canopy cover per acre and the pounds per acre yield of understory grass vegetation., This should be accomplished by methods similar to those used in collecting data for this study. Potential forage production is estimated from the proper canopy / grass production curve in Figures 7,a,l, 7. a. 2, and 7. a ,3, Providing there is a fair seed stock of valuable forage plants left, a prediction of the potential forage increases that are possible through management practice can then be made. If sufficient potential exists, the benefits from increased production can be balanced against grazing deferment "losses" that must be incurred during che 5-8 year rehabilitation period. If existing range conditions are deteriorated or the potential is low due to heavy canopy, tree eradication with some form of seeding practice may be the 201 only way to improve forage production. In the process, watershed benefits may be quite worthwhile, In portions of the pinyon-j uniper woodlands, understory plants are almost non-existent. Topsoil between individual tree litter cover is susceptible to erosion. Tree roots do not have the same restraining effect on soil loss as grass « The chaining process alone, leaving a mass of protective litter, improves watershed con¬ ditions on sites of less than 15 percent slope. If drilling is not contemplated, sites with a high percentage of pin- yon should be given first consideration, not only because precipitation levels might be better, but also because the re-growth characteristics of pinyon should permit greater conversion longevity. While the general rule is to pre¬ dict kill on the basis of number of stems per acre - 7", in no case should chaining or cabling (without slash treatment) be attempted where the tree stand contains 250-300 stems per acre in the 3" and lower diameter classes; longevity of such conversions might only be 20 to 30 years. Longevity can be estimated in a rough fashion by referring to Figures 6,c.4 through 6,c.7 (based on residual tree growth to reach specific percentages of canopy closure) If possible, the slash on non-drilled conversions should be burned. This will tend to increase kill percentage and lower the amount of heavy slash cover If these first steps substantiate the feasibility of eradicating the tree stand, the following guide should be considered for greatest possibility of success . 8.b. Treatment Choice by Province — H. E. Isaacson Escalante-Sevier Province — A. Chain or cable only - Visits were made to only 5 projects which had received this treatment. Four of the five showed a sig¬ nificant increase in production (Table 7.C.1), yet total grass production after treatment was low on all but two. Prior to treatment, these two were open tree 202 stands with good grass cover. Bluebunch wheatgrass and Indian ricegrass made up 40 percent of the understory composition. The recommendation should be to remove tree competition where good productive species already exist. B, Broadcast introduced grass seed and chain or cable - This treatment showed erratic results in this province. Only 2 of 10 projects (Table 7.c. 2) show fairly high production of seeded grass. On a homogeneous site, this prac¬ tice was applied over a period of several years and results differed greatly. Apparently a good year (precipitation wise) is necessary for seeded grass > establishment. A higher degree of success occurs on the windward side (east side) of mountain ranges in a precipitation zone 14 inches or higher. This treatment would only be recommended on extremely favorable sites. C. Chain, windrow slash and drill introduced grass seed - This technique was used extensively in this province. It is the only treatment consistently successful in the pinyon-j uniper type. Latitude may have an affect on produc¬ tion as will site quality. Treatment is highly recommended on qualified sites. Care should be taken in choosing sites because the treatment removes all vege¬ tation prior to seeding. Important browse ranges should not be so intensively treated. La Sal Province-- A. Chain or cable only - This practice is somewhat more suc¬ cessful than in the Escalante-Sevier province. It is recommended only where a good stand of native bunch grass will provide a source of seed. The following species, Indian ricegrass, mutton grass, bluebunch wheatgrass, or beardless wheatgrass, should make up at least 40 percent of the understory composition and should be uniformly distributed. B. Broadcast introduced grass seed and chain or cable - This is the most common practice in the province and is consistently successful on high quality sites. While more forage is produced by clearing and drilling, the broadcast¬ ing technique is cheaper (Table 7.C.10 shows the significant difference in 203 grass production between the treatments on the same sites) . It is highly recom¬ mended on suitable sites. C. Chain, windrow slash, and drill introduced grass seed - Most of the observations of this technique were not eradication projects but involved clearings along power lines and roads. It proved highly successful and is recommended if cost is not a limiting factor. Coronado Province — A. Chain or cable only - With the existing good cover of grass (blue grama, side oatsgrama, galletta grass, and mutton grass) generally found in pinyon-j uniper woodlands, this practice has been used extensively to release the native species. Table 7.C.7 shows highly significant increases in the majority of projects but less than half show significant increases in grass basal area over those of the comparison plots. Thus, much of the increase in pro¬ duction comes from gains in vigor of the existing grass stand. This treatment is recommended for the Coronado province because of the lack of success in estab¬ lishing introduced grass species. Production increases are not as dramatic as successful seeding projects in the other provinces, but production gains comple¬ ment a practice otherwise necessary to halt invasion of short grass ranges, B. Broadcast introduced grass seed and chain or cable - Few of these pro¬ jects show much promise; successful ones were in precipitation zones of 15-18 inches. The practice of burning the area prior to broadcast seeding with crested wheatgrass proved successful on the Haulipi Indian reservation. Recom¬ mendation would be to seed crested wheatgrass or Siberian wheatgrass at sites where the known winter and spring precipitation is sufficient. These conditions are rarely met in the pinyon-j uniper zone of this province. No lovegrass seed- ings visited in the province were considered successful. C. Chain, windrow slash, and drill introduced grass seed - This practice is not common but several places along power lines south of Farmington, New Mexico, provided comparisons of broadcasting versus drilling grass seed. The 204 treatment would be recommended on the same sites as for the broadcast technique,, 8.c. Precipitation Recommendations by Province — H. E. Isaacson A good estimate of average annual precipitation at a proposed conversion location is available from isohyetal maps of Utah and Arizona which have been published by the Water Supply Forecast Unit, U. S. Weather Bureau, Salt Lake City, Utah. A similar group of maps covering western Colorado and northwestern New Mexico are attached to the Upper Colorado River Basin Report, U.S.G.S,. Pro¬ fessional Paper 442 [lorn and Hembre, 1964]. Estimates for Nevada will have to * be made using the best information available. Tables 8.c.l, 8.C.2, and 8.c.3 show how certain species common to the pin- yon-juniper type are related to precipitation zones in each province. This knowledge will be of assistance when making precipitation estimates in the field. Of primary importance when seeding grass throughout the study area is seasonal distribution of precipitation. It is probably the main environmental factor involved in the success of failure of establishing stands of grass. The introduced grass species measured in the study area (mainly crested wheatgrass and intermediate wheatgrass) require early spring moisture to become established. % Province No. 1 (Escalante-Sevier) — The recommended seeding practice (Table 8 e.l) in this province is drilling. This technique proves successful for crested wheatgrass when the average annual precipitation is 12 inches or more. Although intermediate wheatgrass has been successful at sites receiving as little as 12 inches precipitation, the recommended level is 14 to 16 inches. If a broadcast crested wheat project is attempted, it would be planned for a site that receives 14 or more inches of precipitation. Province No. 2 (La Sal Province) — If the grass seed is to be drilled following tree removal, the precipitation requirement is 12 inches for crested wheatgrass and 14 inches for intermediate wheatgrass. Projects that are broadcast sown 205 a CD p cm P P P P CO cO O 4-1 XI p a> P to X o P cm p ai CO a) °H a cd CM CO 00 vo cO M-t P L r> °H i — I CO PO i-i C Csl CO CD 40 a P cr< X XXX XXX X X X X X X X X CO > p P CD P CO p up co 4-1 CD p • 1 — 1 1 P P X B p CM CO O CD 4-» 4-J •p P DP CM 4M 4-1 a) P P X O P 00 • CO CO •H P 6 1 P 40 p CO N p P P CO CO P p 40 X p •H B • CD P X p W a P p p P CO X P 40 P CM a •H CM •H °ri »rl p P •H p O p °H CM 40 °H p (D P CO CO p p a CO > P o p CO O p P p 40 P •p CD <3 < CM co P-1 o CP < PQ Q Pm < CO Pm CJ p P CO o O CO g CO p g 4-1 CO p X o P P CO CO 00 P u 4-> P CO CO 4-1 P 00 P p P 00 40 40 X CD P p CD >•> o • CO CO 40 “rl P 00 00 JP P p CD 40 1 — 1 CD p p CO P rH CD CD £ 4J P p P P * 6 p p p 4-1 40 o P o CM X CD IX CJ B u CO P 40 40 p •H i — l 40 o CO o 40 p CO • CD P CD CD 40 X 00 P 40 a p -X \ — 1 p CD P 00 00 00 CD p P P 40 CD CD CM “rl o P p P p P p P P p B P CM a 40 P CD CD o CO CO CD P 40 P X 40 p 1 - 1 "rl O 4-1 T“ 1 CM g 4-1 °P X °rl p a) CO i-H > & 40 P 40 CO g 00 4-1 P P X > P 1 — 1 £ t— 1 p O P P P o o °H cr P p CD pH p o CD P X o H o PQ 1-1 pp CO CO X & PQ PQ H CO CO X S 206 Table 8,c,2. Common species of the La Sal province as they are related to average annual precipitation c D 1 1 1 l i 1 I 1 1 1 1 I 1 1 1 i I 1 1 1 1 1 1 i CN 1 1 1 I 1 1 l 1 1 1 1 1 i i 1 1 1 1 1 1 1 1 i l 1 1 1 1 I 1 i i i i 1 1 s 1 1 1 1 1 1 1 1 1 i I ON 1 1 1 ! 1 1 l l 1 1 1 1 i i 1 1 1 1 1 1 1 1 i I 1 1 1 1 1 1 i i i i 1 1 1 1 1 1 1 1 1 1 ! 1 i i , — 1 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 1 i p 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 1 i o 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 1 i t i 18 1 1 1 1 1 1 1 l 1 1 1 1 i i 1 1 1 1 1 1 1 1 i 1 1 1 1 1 1 i i i i 1 1 1 1 1 1 1 1 1 1 1 X i X P 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 ■u 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 x 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 CX X — 1 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 a 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 1 1 re 16 1 1 1 1 1 1 l l 1 1 1 1 i i 1 1 1 1 1 1 1 1 i i 1 1 1 1 1 1 i i i i 1 1 1 1 1 1 1 1 1 X PL, 1 1 1 1 1 1 l I 1 1 1 1 i 1 1 I 1 1 1 1 1 1 i l 1 1 1 1 1 1 i ■ i ■ 1 1 1 1 1 1 1 | r— 1 LP) 1 1 1 1 1 1 1 l 1 1 1 1 1 i 1 1 1 1 1 1 1 1 1 I 1 1 1 1 1 1 1 i 1 i 1 1 1 1 1 1 1 1 CCS r — 1 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 X P 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 P 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 p mT 1 1 1 l 1 1 i 1 1 1 1 i 1 1 1 i i 1 1 1 C r H 1 1 1 1 1 1 l 1 1 1 1 i 1 1 1 1 1 1 1 1 1 X X X X X X X X X a> 1 1 1 1 1 1 1 1 1 1 1 1 1 i 1 1 1 1 1 1 1 1 60 CO 1 1 1 l 1 1 i 1 1 1 1 03 r -1 1 1 l 1 1 i 1 1 1 1 P 1 1 1 l 1 1 i 1 1 1 1 a) 1 1 1 l 1 1 i 1 1 1 1 > CM 1 1 1 l 1 1 i 1 1 1 1 <3 r -i 1 1 1 1 1 1 l l 1 1 1 1 X X X X X •N X r -i 1 1 1 1 1 1 l l 1 1 1 1 d) r— 1 1 1 1 l 1 1 X 1 1 1 l 1 1 P 1 1 1 l 1 1 M < D 1 1 1 l 1 1 p H 1 1 1 1 1 1 l l 1 1 1 1 ON 1 X 1 X 1 X l X 1 X 1 X £ P £ p a} CO CO 4-J CO ■u cu p o P CO P X CO p £ p CX P 4-1 X ■M X 4-1 P p ex p CO p CO P X O H P 4-J CU 4-J CO • 4-J o a gH 60 o 0) P •p4 P 4-J P E p CX p 1— 1 ,jH P £ p CL) X • p (U a P P CJ p • o CO CX 4-1 r— 1 p i-H CO P CO £ •H CX 4-1 £ p P N p p p P 4-1 CO X P 60 p CO °rH CO CO p p ex P CX £ N £ cu * p p p p p (U CO CJ CX • CO p P “rl P a X , — i P CO p i — i 4-1 p p p ex a •H CO CX °p4 p 60 P X ex es P •H p p p X o o O p °rH PS o P CX CO P tX ex o CJ CO CO p CO o p P p p £ p p CJ 60 •H CO CO CX p CO o X CO ex X °rH CX i — I CU X X X (U CJ o p P P p o CJ p £ P P £ £ p o ex CO CO CO CO X p P p p p p P p cu CO 60 60 o 60 4-J CO 4-1 4-1 £ o CO p P P a> X P CU CU P pp , — 1 p X a) •rl r— 1 p N P CO p a X 0 60 u P X) P 4J 4-> p p p X o p r~ i P ex x X •H £ , — 1 p 4-J p u •H o cr p H P °rl r— 1 cu PS r— 1 p ex, 207 Pi cd] D a, a, Pij djjl cd] Pi 04 >\\ Pi O 4-1 X) O Pi O X) Pi Pi O Pi O O a; JC 4-1 4H O CO 04 -H 04 04 col O CN CTN o •H 00 4-4 cd 4-1 •H pp rH °rl o 0) VO Pi rH CP t — l IT) cd ! - 1 p! Pi Pi cd 1 - 1 a) 60 CO pi i — 1 Pi 0) > C\J pi rH #\ CO \ — 1 04 rH rC C4 Pi o (—4 rH X X X X X X X X XX X X X X X X X X X X X X CO °r4 CO pp Pi 04 rH ai 44 rH P) X) CO 0) CO d • o qq cj cd rH 3 Pi CO Pi X) •H Pi pi PP °rH 4-J 0) 4-1 qr4 04 X •H 44 Pi Pi PP Pi pi d) PI i — 1 a o 44 pi 44 44 CO • u 44 a E 04 •H •H •H Pi Pi *rl 44 pq Pi a pp •H »r-l cd pi PJ 0) 44 Pi 04 O •H • Pi 44 44 o CO pp i — 1 c q3 CO CO pi qr4 P3 Pi 44 e E e CO pp 04 °H CO CO E o CO 04 o O 2 o Pi Pi P CO 04 CP 04 PP X) E "rl pp n N Pi rH H rH 4-J 60 a Pi PP E CO •H CO Pi CO CO Pi Pi g ®r-l ql > >» CL) Pi Pi Pi Pi pq CO 4h CO Pi Pi a • Pi q> pi 04 Pi Pi 0) 04 Pi ■i-) Pi 44 Pi PP jq N Q) 4-J 13 -Q o 60 Pi xi q> xi 60 Pi i — 1 Pi 44 CO Pi Pi pq O Pi g °rl £ (J rj Pi CJ qH rH H cr Pi rH qq cd qq •H 04 Pi 04 rH Pi 04 p) Pi H u PH o nil PQ pq CO CO M <3 H CJ CO PQ & Q IX <3 CO CO CJ <3 Pq < Ph 208 generally require 14 inches or more., Intermediate wheatgrass can also be used in the seed mixture on the more favorable sites. 4 Province No. 3 (Coronado)-* Any introduction of created wheatgrass appears to require 15 inches of precipitation. The sites must receive fairly heavy win¬ ter and spring moisture. The annual growth period for this province is in the spring;, which is unfavorable for growing crested wheatgrass. / 8.d, Soil Factor Recommendations -- E. J. Eberhard Where seeding is contemplated, all the following factors must be considered Total depth-- Sixteen inches is recommended, but success has been observed with 12-16 inches (texture was medium to fairly heavy) where the soil has a definite B horizon to prevent loss of moisture into the sub-soil. Depth of A layer-- Recommend 7-12 inches but in higher precipitation zones (16 inches or more) 5 inches may be sufficient with a well developed B horizon. Texture of the A horizon-- Good seeded grass production has been achieved on a variety of soil textures. Sandy loam to clay loam spans the texture classes where seedings should be attempted. Outside these textural extremes a decision to seed is questionable. On lighter textured soils (sandy loam) a definite B horizon is necessary for grass establishment and good production. Development of B horizon-- Recommend at least a weakly developed B horizon. A strong B horizon holds the soil moisture in the root zone for longer periods of time during seasonal growth. Tree site index-- The height of both pinyon and juniper trees at a specific trunk diameter at the one foot height should be a good expression of site productivity for seeded grass. But the study did not confirm this relationship 209 Pinyon trees taller than 24 feet with 10 inch diameters measured one foot from the ground were generally associated with high grass production. Juniper should be over 20 feet high at 10 inches to make the same assumption. 8 o e o Tabulated Recommendations -- H. E» Isaacson The information in Tables 8.e.l and 8„e„2 is meant to guide choice of site for growing seeded grass in the woodland type (no seeding recommendations are given for Coronado province). Few sites will live up to all the recommended site factors. If some of the factors fall a little short or into the "possi¬ ble" column, success will probably still be achieved. There are no sharp boundaries where site factors will always predict success or certain failure. Factors interact and some factor limitations will be offset by other factor potentials. Tables 8.e.3, 8.e.4} and 8.e.5 illustrate how "within treatment" seeded grass production varied with site factors. 210 Table 8.e.le Recommendations for seeding plnyon-j uniper stands in the Escalante-Sevler Province 03 4- 1 d 0) 0 4J 03 03 5- i H d 1 X 03 X X 54 o 1 — 1 03 X c 1 03 54 • d 03 03 03 X 1 54 1 X ex 03 o X 60 o 03 4-1 03 X 4-4 54 X X d 03 X 03 03 03 4-3 ex 03 4-1 03 d X CJ 03 •X > 03 X 03 03 03 o 03 d 03 o o 03 o X •X 03 03 X X X B B . — i X °rl X 03 d pN X H X 54 X O CJ a 03 03 03 b [3 X r— 4 d d 03 4-4 d d d d O O > o 03 o 03 d •rH 03 d 03 °H •H °H r— 1 rH 03 X X 03 X X ex o 03 £ g X 03 X X . — 1 X X O g + + pN 4-3 03 03 03 03 03 03 r— 4 0 d 5-4 X o T— 1 X 03 rH 03 03 •rH 03 d 60 6 03 03 B d 03 X 03 u 1 vO d rH rH 03 o3 X 03 •rH d d X X 0) o d 03 03 CN) rH 03 a 03 54 54 03 54 •rH rH •rH o X •H 03 PC rH C/3 CJ 60 6 60 X X o 03 03 rH X 03 > 0) 03 > X u X , — 1 X 03 X o >•> 03 03 . — 1 1 X 03 X 03 X X 03 X 03 a) “H i — I 5-i X X CJ 5-i O d ‘X ro x cj X d 03 X a; oj w a 03 CO r— I 03 X 03 03 5-1 cj 60 5-4 4- ) O 03 o3 cj d X) -H o3 03 O x 5- i CJ PQ 03 H X 03 a x x d o 03 X O 03 5-4 O 4-1 cj o3 MH 03 CJ •X 60 O r— I o cj w 03 03 rH X •H 03 03 O P-4 X 03 X d 03 O a 03 pp; 03 03 03 O P4 03 03 03 03 03 03 XXX a a o o3 oj 03 d d a o O X) o 4-1 b 6 cl o rH Q3 > 03 03 X b •H •rH •rH . — i rH X 03 ®H 03 03 u 03 > r\ >•* 03 03 X O 03 X d d X >-> X X 03 X 03 d o 03 X 03 jH o i — i rH r-'- X o3 X X 03 03 M . — l X P4 X o H °H 1 I 1 d . — i 03 03 03 X > 03 X CNI CNI LO 03 O 03 X 60 X 03 o3 X a rH r-H C/3 & CJ 03 CJ 03 •rH d X d 03 d X d X d o pN •rH pN 03 •X o X 1 o 03 X X X X o 03 X 03 E rH X a) • o 03 ex X CL 03 03 X d o X X X 03 03 03 O 03 X •rH X o d o B 03 03 03 03 6 B rH X rH 03 e 03 60 o o 03 03 03 X X X 03 03 03 £ d 03 03 Cl. 60 O 03 a a a o O > 03 X d 03 X 03 rH 03 X d d d , — 1 rH 03 X 03 X •X CJ o X Pn oj 60 •H •rH •rH X 03 03 X 0) o3 CJ CL, X P>N X rN Pn X 03 X d 03 e 03 X rH + + + X 03 rH 03 0) X X d 03 , — 1 Pn 03 > d X 03 d X rH 03 X 03 d d a rH X 03 d X 03 •r-4 d 03 4-1 03 03 03 d-, 5-4 X d O 4-» O O M-4 d MH 60 O "X O 03 X 03 X 5-i d 03 C 03 03 03 03 X W 54 44 12 C/3 O C/3 d o N •rH 54 O X X O PQ X d N X CL, o •X m 03 d o) N X o 03 o X •X o 03 •X X X X X < — 1 o d O d *x X < 03 X • • X o 6 03 •X 03 < 03 CL 03 X CL, X o 03 d •X , — 1 X d rH *H 0) CJ 03 X X 03 CJ g 0) X CL X P> 03 g X o 0) 03 03 CL o p4 Eh Q H Q C/3 o cj - d 03 5-4 03 03 03 03 X 03 a d CL. 4.4 03 03 03 X 4-4 54 03 > d o X °rl a 03 03 u d 03 X X 03 X 54 03 03 <44 03 03 X 03 4-3 03 O 54 23 03 X °H d X d X o3 03 d X 03 X 03 o X X 03 03 X a) 03 •X X a X 03 o d •X 03 X X 03 03 03 X d 03 60 X X d a °H o MH o CJ »H °H d d X -H X 03 03 CL d °x X d 60 03 03 o d 03 X r/3 X •X X •X 03 X d C/3 03 03 03 X rH X 03 XI 03 03 03 03 X 03 X X 03 X 03 d o rH d 03 o X °H o X •X o X 03 03 d X •X a o •X X d 03 X d 03 X X r o X 03 CJ X CJ CJ X d 0) & X > 03 03 o OJ 03 X X X £ a) X 03 CL O X X X X r\ d 03 CL 03 03 • C\ X d B 03 d o o B X o X o 60 jH 03 60 a X B 03 03 a o X X > d 03 03 •X X • X X X o X X d o 03 X d w 03 E E CL 03 03 0 X CJ 0 0 03 X o 03 03 CJ 03 03 03 X X X 60 X 211 Table 8.e.2. Recommendations for seeding pinvon-i unlper stands in the La Sal Province CO a) 1 CO > 03 P CU •H 03 o CU CU 03 CJ P d p CM p d a 60 03 03 03 CO CO CO O d 03 33 d a 03 a) cu CU £ £ rH °rl CO •i-l 43 03 43 43 43 03 03 (U r\ p P 03 co d CJ a O O > cd o CU 03 43 a •r-l •H CU U a a 03 o5 CU £ cu d P P P !— 1 d d d O O 03 p 03 •r-l CJ O 43 “rH •H «H r— 1 rH 03 43 43 3) •H P^ CU CO CU P •H 03 d CO -3" vO >> P>^ i — i P CO 43 43 O CO i — 1 i — 1 03 03 4*3 CO 03 P P d P 03 O 1 | 1 d tp 03 (U p cu •rH CM 43 Pm CN CN m 03 o cu p 60 d •H O 1 — 1 r-H C/3 & H > CU CO 03 p CO (U CU •r-l 03 p 43 d P 03 •rH 60 4-1 03 1 P MH d O CU P O CU ( — 1 03 P CM o3 P 03 cd £ d od CO CO CO O r-H CO p a (U d d d i — 1 X — 1 cu 03 03 cd d H g •H °H •H 03 CU CO £ r’-r 43 o 03 g P’'* p^ P CO 03 d o + + + 03 03 1 - 1 CO 03 cu d P cu 03 a d r-H 1—1 43 43 CU MH 03 P P d co a 03 P •rH CO CU P P 03 P CM 1 O 43 03 •r-l o CU CO 03 a a a 03 03 cu b a i — l H r— 1 03 cu d d d O O 03 p cj f— 1 °H “H •r-l r— H 03 CO CO CM 03 03 43 (U CO °rl •r-l oJ °H 43 I — 1 P CO 43 CU CO o CO X — l l“H r- 03 03 4*3 CO 03 P CU P 03 p CO 1 1 1 d r— H 0) CU p P •i—l 43 PQ o CN CN LO 03 O cu p 60 O d CO PM i — 1 x — 1 CO & CJ P p P d X CU °H a) '‘H CU 43 rH P P 43 rH p 03 03 i— 1 1— 1 d CU CJ 03 CO 43 O CO p^ p Mh o CU P o CP 03 r-H 33 CO d £ O r-H 00 o P CO g 43 CO o o d 00 CU P H p • CU •H 43 d o cu 03 43 •rH o p o od p P •H p d CJ o Ip p p a) CU a • 0\ 03 cu 03 d (U °rl CO CJ > 43 33 d 43 43 P 33 CM d -H 03 CU £ 03 o u 3 C/3 43 C/3 P Q MH H O •r-l 43 03 P P cu a cu CM o 4d o3 03 33 P d P d CO 03 O 43 o CQ (U CU CO O • P P d N 03 MH 43 g 03 P p o PM o bH MH cd cd 03 o3 •H 43 p CU g rH CU P o P O CU (U CU o CM o •H CU MH w PM H O H Q 43 CO CJ £ CO cd 212 Table 8.e.3. Examples of low, fair, and high productive grass stands in the Escalante-Sevier province follow- ing treatment by windrowing slash and drilling crested wheatgrass seed after chaining Degree of success3 i T-U • T) d) Xl H G O G rG G X G CU 0) +j G G o CU o cu aH X Pn G G , 4-4 G G G o cu XI G B •G •H G CU 4J PU CO 4-1 U a. H G CU CJ G o cu cu cu G 'v. B r— 1 •H Pn o G XI ♦ CO CO CO G cu a G cu 4-4 O CO CU CU ai O > CU 1 - 1 4-4 G G X X rG rH CU 4-1 44 G ■rl G CU i — I cj cj O XI CU CU $ G r— 1 00 o G G •h m S'? IP O CO G a) S'-? CN oo H o CU G CC iG ut r— 1 i — 1 rH CO £ LO CN i—4 00 r— 4 ■”3 G O X rG cu O cu 4-4 4-1 CJ a rG rH X) CU CU G G CJ cu CU •p-i •H G G IN 4-1 B^S S'? °rl O S'? O 00 CN O rH o o CO CO rH CN i— 1 VP UP CJ cu CN r— 1 G o •H CU 4—1 G o a G G XJ O CO G rP CU r-4 £ CN O X X X cu 4-1 4-1 o o CJ XI CU •G •G G rH G rG CJ G O CU O 4-1 G CU G CO G Po PQ rG 4U G MU o CU G G Pn °G rG G rH 4-1 < * 1 — 1 CU 4-1 4-4 P’'! G • 4-1 G o G CU rU < O G G B u rH $H G O CU CU CU 4-1 •G G o w co eg CU EG Q H Q CO CU X CJ XJ CU 4-1 CO a) G u G O °G 4-1 O G XJ o G cu Pn g X3 I G “H <3 G 213 Table 8.e.4. Examples of failure, fair success, and successful grass stand in the La Sal province for the _ treatment of broadcasting crested wheatgrass seed prior to chaining trees TO G a) TO (U cO a) G Q) 4-1 4-1 G G a •H CO o 4-1 o CO cO X tH 1 - 1 '■ — . CO CO CO 0) a) G G CO a) 0) G 4-1 rO JG rG rG a) 4-1 4-1 (U CO i— 4 o u a B TO CU CU 1 - 1 CO S'-? G G G G a) 0) t- 1 cu O 04 •G jG •H °G i — I O 4-4 4-1 G CU G G O G CO TO G TO cO o •G CO G CJ G CO N G cO co cO cO CO CO CO cO °H O 4-4 G 4-1 - — CU cu CU CO o G •G toO CO • rG rG rG -G 4-4 O O 4-1 G rO a a u 4-1 cu CU a) 4-» rG cO O TO G 1 - 1 G G G CO G (U cu 4-1 4-4 CU •G B^S •G °H qH O o 6s? 4-4 44 rG PQ •G TO CO cO B S3 LO •G P G CU P O » — 1 Cu X > O G G g a I — 4 G G O Xd p -id P i — l -id -id rP !— 1 CU p p id H p • a o o a Xd CU cu •H <*) o P o id P P Po CU cu -id -C o «h °H •H Xd p 4-1 4-1 Po 0) id 60 60 CM b^? id o rH °H cd •H °H i — 1 s-s vO uo o cD cd o S'-? i—1 CN id -id Jd CU Pd NT CO i— 1 CO co p uo CO CN O p p -id p P id o p CU p O CU B CJ • P p cd id P o o p o a cd i— H N P CO CO CO CU Pi H xd • CU cu CU > cd p O CO dd 4d dd CU p P cu o P -Q o CJ o xd cu cu > -£d C4 i — 1 id id id cu (U •H •H •H p P 4-1 4-1 pd p o B^2 i — i o rH •H O 6s? vD ^D CD •H o B^S O id CO cd co 00 CN ! — 1 CN CO p uo CN t — i o •H p4 e CO xd xd p p id id id O cd cd id cu P CO O CU B a id “H P p cd o o P CJ o p N O o cd X3 rH p P CO CO CO id CU Pi P xd cd o O CO dd rP jd CO (U P p cu -c 0 cu cu PQ p °H *H 6 Pi p 4-1 Po p £ o ' B^2 cd cd r— 1 > •H -id p -p P O • i — i p P p o id • p cd o cd p jd C cu CO p -id • • u id p CU B CO -id CO •H cd •H xd C (U p cu p p 60 cj P p o id td CU id O CU °H tH -p P rH H o p cu rH P. cu O cd p p cu id Po •H B o o o id id B u r— 1 p p o cu cu cu p H p o w an H p H a H Q CO p lx> CJ 215 Air-dry production crested wheatgrass in lbs. /acre. 9. VOLUME-TABLES AND TREE PRODUCTS R. J. Rivers That pinyon-j uniper woodlands do have usable products is not disputed. The questions of how much and how valuable are debatable. Unfortunately, the answer to "how much" of any given product these lands have can only be answered with a woodland inventory. "How valuable" depends on market demands and trends in competition from substitutes. (See Vol„ II of the report.) Traditional products are pine nuts, fuel wood, mine props, fence posts, and Christmas trees. (In recent years some research has been done to determine the technological factors associated with charcoal and essential oil potential of these trees,) Since most of these products are marketed or utilized when within, fairly narrow dimension ranges, management decisions must be based on some know¬ ledge of growth rates. At present, data concerning the time it takes to produce a given woodland product are scarce. Chapman and Behre [1918] indicate that 150- 170 years are required to produce a commercial grade mine prop, and approximately 73 years to produce a commercial (juniper) fence post. Several volume tables for P-J woodlands are available. Probably the most thorough were prepared by the Soil Conservation Service [Howell, 1940], Karl E. Moessner of the Forest Service has also prepared aerial volume tables for P-J stands [#69] . These volume tables are unique in that they facilitate aerial surveys of woodland stands for potential products such as fence posts, 9, a. Volume Tables The volume tables presented in this discussion were developed from basic data presented in Table 8, page 36, and Table 10, page 38, of S.C.S. Regional Bulletin No. 71 [Howell, 1940], Therefore, a brief discussion of the field sampling methods used in that study is in order. 217 The data were collected from 39 sites found in Arizona and New Mexico. The trees used in volume determination were cut to 4' lengths and down to a 2" dia¬ meter. Volume was calculated using Huber’s formula [reference 6]. Cubic volume per tree for given diameter classes was next calculated. Since only partial coverage of height and diameter classes was provided, the original number of volume observations has been increased by applying Schunacher’s formula to the original height-diameter measurements. This analysis developed the constants necessary to predict volume for any chosen height-diameter relationship [reference 7]. Log V = Log a + b Log D + c log H , where V = Volume in cubic feet D = diameter H = height. Juniper : log Y = 04.6258 + 2.270 (log D) + 0.359 (log H) Piny on: log Y = -11,4321 + 0.2039 (log D) + 4.0513 (log H) . These formulas plus the appropriate conversion factors (to convert cubic feet to cords) were used in the construction of the Volume Tables presented in tables 9. a, 1 to 9. a. 4, The Juniper Volume Tables were constructed from data listed as Juniperus monosperma, however, it is likely that the trees actually used would now be classified as Juniperus osteosperma. At the time the S.C.S. Bulletin was pub¬ lished, confusion existed over the form and range of these two species. The 218 Table 9.a.l, Pinyon volume tables (cubic feet) Dia. @ 1' 5 10 15 20 Height 25 , 30 35 40 45 2 0,009 0.149 0.771 4 0.011 0.182 0,943 3.025 7,472 6 0,012 0 a 205 1.061 3.403 8.405 17.594 32.855 8 0.013 0.223 1.153 3.700 9.138 19,127 35.717 61.352 98.870 10 0, 014 0.238 1.230 3.948 9.750 20,408 38.108 65.459 105.488 12 0,251 1.297 4.162 10,280 21.517 40.180 69,018 111.224 14 0,262 1,357 4.353 10.750 22.502 42.020 72.178 116,316 16 0.272 1.410 4.525 11,175 23,392 43.681 75.031 120,915 18 1.460 4.682 11.564 24.206 45.201 77.642 125.122 20 1,505 4.828 11.924 24.958 46.606 80.054 129 010 22 1,547 4.963 12.258 25.658 47.913 82,301 132.630 24 1.587 5.091 12.572 26.315 49.140 84.407 136 . 024 26 1.624 5.210 12.868 26.934 50.295 86.392 139,223 28 1.659 5.324 13.148 27.520 51,389 88.271 142.251 30 1.693 5.431 13.414 28,077 52.429 90.058 145,130 32 5.534 13.667 28.608 53.421 91.761 147,876 34 5.632 13.910 29.116 54,370 93.391 150,502 36 5.727 14,143 29.603 55.280 94.954 153,021 Table : 9 , a , 2 . Pinyon volume tables (cords) Dia. rM 4-1 i — i rH H ON n- in •iH 5m CO o p •r— 1 rH o id d 1 1 1 (U d d d cu cd i 1 1 1 rd. o -r— j t> u 5m 5m X CM'—' 5m d a) d a) d CU CU d d >M d cu X N o CM o PM CM o o o d CM CM 4-1 to •iH 5m CU II CJ rd CU X 4-1 5m i — 1 rH i — 1 |-M rM T“— 1 rH d a H rH X) CO d z CO d o 4-1 cu CO d CO O 5m d 44 1 E CM CJ CM d z +j o 5m • r\ CN CO 5m d 4—1 CU cu •H 4-4 a) CO CM rd CO d X (U 5m O 5m co X a o •H •H 54 X d X d 4-1 CU £ CM & d CJ 4-1 CO 5m d CO d MH •H cd O o O •H O d a) CJ PM Pm £ P E • CO 4-1 CO rd CO CM 1 - 1 CO X rH O O 4-J O d CM 5m o CJ o O CM CO d £ o (U 00 x rH 5m X cj CO o G rH G CD X i— 1 CD rH <4H O G 54 rH X O C 4-> < r— 1 O G 4-1 "H CO O °H • 4-1 G • X G rH G 6 CN CO G CO 1 X CD 54 54 X 1 - 1 t— H CD G C G °i— 1 X X G O B G iH X CD CD X CO o cj X o VO o CO 1 too o £ X o G 4-1 cj U~> °rl 54 G p CO O X G p G X o °H •H CD 54 X X 54 X p X CO < CD •H 4-J CD £ G CO CD • CD 54 CD 4-4 T— 1 > X X O I G o cj too CO C CD *1— 1 X X "H G G CO O 1 - 1 •H CJ G X CD G O G toO •H 0) G CO 5-4 54 • 54 a O rH CD CD Fh > P CO CD X CO ®r4 G X CO CD ai 54 X > rH G CD o G > CO 54 CO 54 CJ o CD P CD G •H 5-4 X g X X G P °r4 °H •H i — I CD 6 CO G CO G rH ■ CN ■ 1 E 1 E E X X X CO G CD X G X * G CD CD rH E CD X CD rH ®r4 toO X CO G •X CO G CO CD G CO CJ E CD a a G X CJ G CD G •H X •H • • E 1 - 1 CN •H X 232 REVIEW OF UTAH P-J REPORT The report, "Management Alternatives for Pinyon- Juniper Woodlands - Part A, has been given critical review by several members of the Bureau’s technical staffs. It is a very complex document containing several parts covering different aspects of the P-J type study. The dominant effort emphasized through the report relates to providing a site quality index and making it correlate with all other type evaluation factors: The degree of success here is uncertain and will be discussed more later in this review. To lend some order to our comments, each identified portion of the report will be treated in sequence beginning with the preface. In this intro¬ ductory portion, we note with a touch of apprehension the comment concerning possible inaccuracies in project identifications and tying them with office records. We must assume inconsequential errors in this respect. Also, the frontispiece referred to is a low quality map from which almost nothing can be definitely discerned. A larger scale with better drafting of study locations and other features would have served the intended function . The table of contents would have been more enlightening if the names of the authors of each portion of the report had been appropriately inserted through it. Section 1 augments the preface in describing circumstances and personalities involved in the initiation of the study. Time f . « ' not described as being such that only Bureau are alluded to, but are one year’s collection of each type of data would be possible. This is perhaps the greatest deficiency of the study, prohibiting the evaluation and sampling of annual fluctuations in weather and production. Section 2 is devoted to a description of field methodology for collecting forest, range, climatic, and soil and site data. Most of these procedures and most of the evaluation criteria measured seem entirely satisfactory. However, -the method of selecting plot locations through the site tree designation procedures used appears to bias the data. Evaluations, therefore, would not be representative of typical site conditions. The tallest, most perfect tree found was designated the site tree. Such superior or elite trees hardty typify overall site productivity, and their growth characteristics differ markedly from that of the general tree stand. Section 3 describes the ecological provinces used, some of the main characteristics of the P-J type, and restrictions imposed in sampling. The map showing the provinces is quite crude. It could be readily refined in several respects including province delineation and drafting quality. A disappointment was the discovery that only the flatter and more gently sloping sites (up to 15$) were studied. Obviously this was due to an assumption that steeper sites would not be treated. It apparently was true that steeper slopes had been infrequently treated up to the time of the study, but many of these more mountainous areas can be successfully 2 i / / . ' converted, especially for wildlife habitat development purposes. Such areas are now being treated, but without the benefit of definite study criteria on which to base these operations. The ecology of these portions of the P-J type needs study as well as the flatter areas. Perhaps soils would have taken on greater significance as a controlling element in P-J ecology if these steeper areas with shallower soils had been included in the analyses . In the vegetation composition tables of Section 3? such terms as "abundance classification" and "percent construction" should be defined. Otherwise, data interpretation will remain questionable. Certain other terms used elsewhere in the report are also subject to varying interpretations and should be clarified. Section 4 presents a scheme for site quality classification through use of a tree index. This is the most questionable portion of the report. The rationale behind using a height/diameter index to reflect site pro¬ ductivity needs more detailed and clarifying discussion. First, the objective in determining a site index is not clearly discernible from the information given. The impression is gained from report contents that this index is meant to relate to all possible biological products of the site. This appears to over-extend the capabilities of such an index. Usually forest site indices are related to volume increment of wood, and this may be an objective here. However, more attention seems ■y 3 . to be directed toward correlations with understory production. The report offers the speculation that tree site index should be a good expression of grass productivity, but such is not confirmed by the study. The decision to offer only one site index for the entire P-J type, that being the height/diameter criterion for pinyon only, is viewed with uncertainty. The point is made in the report that the Coronado province out-produces the other two provinces in both trees and understory; how¬ ever, when seeded to introduced species of grass the Escalante and LaSal provinces are far more productive than the Coronado. These circumstances present a series of questions concerning the proposed site quality index. Using an overall index, it follows that a preponderance of the highest rating sites will fall in the Coronado province. If separate height/diameter curves had been provided for each province or subprovince, such rating discrepancies would no doubt have been evident. Since trees grow much more rapidly (as shown by the height/age and diameter/age curves) in the Coronado province than in the LaSal, height growth by the time 10- inch diameter is attained will probably be greater there also. Therefore, some degree of correlation perhaps exists between the height/diameter index and volume increment. This constitutes, at best, an indirect con¬ sideration of the indispensable production element of time. A direct involvement of tree age in the quality index would probably have been desirable, regardless of the problem injected by generally uneven-aged stands . 4 Even though there may be a correlation between index and volume growth of trees (although unproven in the study), the relation between index and seeded grass production must necessarily be erratic. Such plantings are not generally successful in the Coronado province. Index correlations with increased production response of understory species after tree removal is not elucidated even for the leveler sites of the P-J type studied. No evidence nor rationale is presented to back up the apparent assumption that a site index based on tree growth characteristics will satisfactorily predict herbaceous plant production. Any feasible use of the pinyon site index presented would seem to be predicated on its separate derivation for each dissimilar physiographic or climatic region. The three provinces may not be adequate breakdown for this purpose; the subprovinces might. Even then the only hope of this being an adequately sensitive system to reflect productivity must be based on the assumption that tree height growth will accelerate at a greater relative rate with site quality increase than will diameter increment. Otherwise, the index (height/lO" diameter) may tend to remain relatively constant for sites of different productivities. A most helpful addition to the report from the point of view of reviewers would have been the plotting of actual field data on the various graphs. From plotted point dispersions, a better idea could have been obtained of data variability and validity of correlations. A table of correlated values taken from each of the graphs would also have been very helpful, since it is impossible to accurately take such information from the rough illustrations included in the report. 5 . . Section 5 presents a good development of soil site factors important in quality evaluation, and a very enlightening review of pertinent literature. The general study limitations on time and restriction of sampling to gentle slopes made inroads on the completeness of this phase of the study also. An additional bias was injected by taking soil samples from under the crowns of site trees. Other situations in P-J stands were not sampled . Section 6 contains a lot of good information on tree characteristics in relation to control success and describes the means previously used in P-J control operations. Some good guides to predicting success of treat¬ ment are given, such as minimum required tree heights of 10 feet and the percent of 7 inch diameter trees and over needed. The procedure derived for predicting longevity of conversion results was interesting. Here again, however, discrepancies in rates of tree growth in different ecological areas appears to require that specific derivations be made for each dissimilar area. Section 7 presents a good analysis of range forage values based upon the limited data obtained. Careful attention is given to the inverse relation between tree crown cover and forage production, and it was interesting to note the difference in response of shortgrasses and bunchgrasses to tree cover. The discussion of grass production resulting from three different con¬ version methods in the various provinces is most pertinent and presents 6 some definite physical guides for method of treatment after a decision is made to convert to a non-tree cover. (The economic criteria for conversion decisions are included in Part B of the study report.) The hypothetical derivation of estimating equations for forage response is also an interesting proposal. However, the specific equations presented for each conversion method are of questionable validity since they are based on just one year*s production data. Section 8 is apparently based on the presumed conclusions of Part B of the study on economic considerations. It is assumed that, except for special cases, the best current use of the type is to provide forage for livestock and wildlife. Alternatives for management suggested are livestock use control and tree eradication to increase forage. The recommended conversion criteria and discussion of treatment alternatives for each province are generally acceptable and should prove helpful in making P-J management decisions. The main deficiencies relate mostly to conversions for wildlife habitat and watershed protection and to restrictions against treating sites with over \jj0 slope. Some successful conversions on steeper areas with other favorable site qualities were being made at the time the study was in progress, and several have been successfully completed since. These involve shrub seedings as well as grass. 7 ✓ . The other major point of critical interest is the indicated lack of correlation between herbaceous production and the proposed site quality index . Section 9 includes volume tables prepared in Arizona and New Mexico some years ago by the SCS and some cursory information on various P-J woodland product uses. The volume tables would be usable, where derived only, and the value of extending these by further data collection is questionable as explained in the report . Of the products considered, only for Christmas trees was any substantial amount of data collected and only for this product is the recommendation made to extend product studies . This appears to be reasonable until better prospects for other economically feasible uses are developed. Section 10 presents some possible criteria for a woodland inventory and a range production inventory suggestion. The woodland inventory procedures involve classifying P-J type areas for the various multiple uses. The proposals may be useful in establishing a basic management inventory system for such areas. The range forage prediction system is interesting but presumes, among other things, that a valid correlation exists between site index and forage 8 ✓ production. . • The title of Part A, Ecology of the Pinyon- Juniper Type of the Colorado Plateau and the Basin and Range Provinces, implies a broad and comprehensive treatment of P-J ecology. This study is far from such a complete coverage. Imposed time limitations precluded the basic investigations that would necessarily have been included to identify and evaluate the physical and biological factors involved and their interactions. An analysis of historical changes in the type and the identification or development of conversion means to meet current and prospective future needs and use demands would all be part of such a study. It would require an extended period of time to complete a series of such basic investigations. Part A had three expressed objectives . The first, to develop ecological criteria for classification of P-J sites, was met. A set of criteria is presented, although its extent and degree of development was limited by time allocation. The second objective, to develop the minimum essential ecological data needed for management under various alternatives, may be considered as met depending on decisions of management needs which apparently have not been made even yet. A fund of ecological data was amassed during the brief study; and, from a management point of view, it appears minimal. The last objective, to clearly identify the multiple products of woodland ranges, was met. These products were listed, and their relative importance implied by the extent each was treated. Interactions between these uses was not probed to any adequate extent. Again, such in-depth studies would involve results obtainable only over periods of time not here provided. It was apparently assumed that the competitive -complementary- supplementary relations would be covered in Part B on economic analyses. 9 * This study was necessarily restricted to evaluations of existing P-J treatments and uses. This meant limiting field data collection to untreated P-J stands and sites converted to herbaceous cover. The lack of opportunity to make trial treatments and product studies as part of the research project appears to account for inadequate consideration of multiple use alternatives and products. Additional light on the validity of the site quality index is needed, along with some manifestation of the statistical quality of the data collected and used in arriving at conclusions. Mention has been made of the poor quality of many of the report’s illus¬ trations. The document also needs to be carefully edited to eliminate a variety of spelling, punctuation, and composition errors. We hope this review constitutes a fair treatment of the report. We think it points up some problems of importance in adapting the findings for use as Bureau management guides . We regret that a more complete ecological study over an adequate period of time was not provided. 10 ■* Mapping unit Map Slope Management Management Mapping unit designation alternations limitations (minimum) co 01 5-4 O 03 O •vl- vO CD CL to 4-1 01 rC 4-1 rH J3 £ 4-1 cd •H 5-i £ X) rC CO ■P 01 °rl °H £ 54 cd <4-4 > O co 4-1 O 0 CO X) 01 o 01 5-4 5-1 CL CO 4-» 4-J 01 CO CO 0) O Cd 5-i CL B 4-1 4-1 CO g 01 CO X O X Cl "H 0) 01 ®pH 0 a 5-1 •4-4 rC 4-1 cd 01 X CO cd 1— ■ 1 u rH 5-4 01 X X 01 S-i o • ft i— 1 4-1 a o T - 1 Csl •H cd 01 & & Pi I CO H G °rl CO £ ’-H X *T3 aj CO 01 cd £ cd > cd 01 5-4 GO 54 5-( 01 G X cd CO x X 01 4-1 4-1 ci 5-1 CO »H °i— i X °H 13 c 01 01 CO X 0) <4-4 X cd 01 01 u •H CO 01 > CO r- H 5-4 54 54 "rl X 01 <3 01 4-1 • rH 4-1 x cd 1 — 1 H cd • G 5-4 ps rH 3 4-1 + 6-S O 00 CO 01 •H 5-4 cd > X Is a cd H 0) rH rQ cd GO cd G CO cd 01 B 4-1 1 °r4 G CO O £5 CO CD 4-1 CO X 0) > 54 01 co 01 psj 233 *In this case inaccessible means one that could be developed by a proper road system,, Areas that will always remain inaccessible should be designated NM. Upon completion of a broad management classification of the pinyon-juniper woodlands, the next step would be to inventory the areas designated as multiple use and limited management sites. Inventory methods — In Tables 10. a. 2 and 10. a. 3 relationships developed in the present study, which could be utilized in inventory procedures, are displayed. Table 10. a. 2. Pinvon sp . relationships Relationship Site index 11 ' -17 ’ 18 ’ *-23 ? 24 ' -31 ' ll’-20’ 21f-31' Ht/Cr diameter - Section 4 c - - Ht/age (Figures) 6.c.l 6.c.l 6.c.l 10. a. 1 10. a. 1 Ht/diameter (Figures) 9 . b . 1 9.b.l 9.b.l 10. a. 3 10. a. 3 Volume tables - Section 9. a - - Table 10. a. 3. Juniper sp . relationships Relationship 11 '-17 ' Site index 18 ’ -23 ' 24 ’ -31 ' o OJ 1 r—H r— 1 21 ’-31 1 Ht/Cr diameter Ht/age (Figures) Ht/diameter (Figures) Volume tables 6 . c . 2 9.b, 2 u v_- L. L 1. U 11 *"T • v— 6 . c . 2 6 . c . 2 9.b.2 9.b. 2 10. a. 2 10. a. 4 10. a. 2 10. a. 4 uLL L J.U11 y * cl The most suitable photo scale for woodland inventory would be 1:20,000; with this scale it would be possible to determine the tree heights and crown diameter of the dominant trees. It will also be possible to determine crown cover percentages in 5 percent intervals. Given tree heights, ages and dia¬ meters can be estimated. It is then a simple step to obtain volumes. If suitable aerial coverage is not available, it will be necessary to obtain a g neralized estimate of stand height and densities by using the best photos available as well as ground and aerial reconnaissance. 234 The following map designations for the inventory management sites are suggested (Table 10. a. 4). The minimum mapping unit should remain the same as that suggested in Table 10. a. 1. Table 10. a. 4. Crown Cover Suggested inventory management symbols Use with 1:20,000 photos Site indices 11-17’ 18-23' 24 ' -31 ' Use with scale greater than 1:20,000 Site indices 11 ’ -20 ’ 21 '-31 ’ 1-20% 1/1 2/1 3/1 1/1 11/ 1 21 ' -40% 1/2 2/2 3/2 1/2 11/ 2 40% & above 1/3 2/3 3/3 1/3 1 1 / 3 Species designation should be P: stands 80% and more pinyon P-J: stands less than 80% of either species J: stands 80% and more juniper Proper diameter, age and volume associations can be employed for more detailed study and inventory of the sites that have been specifically selected for woodland management. Recommendation — Sufficient material has been developed in the present study to suggest the basic relationships necessary for a preliminary inventory of P-J woodlands. Sufficient field work should be carried out to refine the volume tables and to determine the best working procedures. 10. b. Range Inventory in Pinyon-Juniper Woodlands: A Suggestion — R, Js Rivers and A. LeBaron The purpose of this section is to consider some aspects of range inven¬ tory needs in pinyon-j uniper woodlands. It is an extension of comments made on pages 163-164 supra. One suggestion is to experiment with aerial photos 233 Height (feet) Figure 10. a. 1. Pinyon Height/Age Curves 236 Total-Height Feet Figure 10. a. 2. Juniper Height/Age Curves 237 Height (feet) Figure 10. a. 3. Pinyon Height/Diameter Diameter at one foot 238 Height (feet) Figure 10. a. 4. Juniper Height/Diameter 239 as an inexpensive means of surveying "potentials" for grass production. Since crown diameter or percent crown canopy per acre can be readily estimated from such photos, direct use can be made of Figures 7.a.l, 7. a. 2, and 7. a. 3. If these charts are entered with percent of crown canopy, estimates of "potential" forage production can be obtained for areas within every province. The more elaborate the photo coverage, the more appeal such a system might have. However, the need for range surveys or studies of range "potentials" is not confined to static estimates alone; many times estimates are needed for longer or shorter management periods. Tree canopy/age relationships developed in this study suggest a means whereby time may be brought into calculations involving allotment stocking rates, etc. The necessary relationships are contained in longevity/prediction charts presented in Section 6.c and in the crown-closure/forage production estimates shown in Section 7. a. Both these studies are based on the common denominator of crown closure. The charts developed in Section 6.c were for 50, 30, and 10 percent crown closures. These same values can be read directly from the abscissas of the charts in 7, a , The possibility of combining both sets of information is, therefore, apparent. Using Figures 7.a.l, 7.a»2, and 7. a. 3, it is possible to write Table lO.b.l as follows: Table lO.b.l. Listing of crown closure and production estimates Crown Province Closure 1 23 10% 300 lbs/ac . 530 lbs/ac. 450 lbs/ac . 30% 100 lbs/ac. 230 lbs/ac. 190 lbs/ac . 50% 40 lbs/ac. 80 lbs/ac. 50 lbs/ ac . The next step is to enter the appropriate longevity/predict ion chart and 240 substitute the grass production estimate from Table lO.b.l onto the curve for the corresponding crown closure. Figure 10.b„l illustrates this procedure for 24-31 foot juniper species sites, province 2. This chart is basically Figure 6.c.6a, with the forage production estimates substituted for crown closure percentages. The same procedure may be followed for all 12 longevity charts presented in 6.c.^ The map designation suggested in the previous woodland inventory section could be utilized. The only variation is that instead of a species designa¬ tion, a grass production designation would be used. For example: (A) 0-50 lbs/ac.; (B) 51-100 lbs/ac. ; (C) 101-200 lbs/ac., etc. ^In effect, this procedure makes only the crudest allowance for effects of site differences on forage production; different sites mean only that the "potential' will exist for varying lengths of time. 241 242 Number of Trees Per Acre