Historic, Archive Document Do not assume content reflects current scientific knowledge, policies, or practices. & jrestry Research West Forest Service U.S. Department of Agriculture June 1982 .< — -i Forestry Research West Forest Service U.S. Department of Agriculture June 1982 In This Issue page Prognosis: fortune-teller for forest stands 1 Timber harvesting and water quality in the Bull Run Municipal Watershed 4 Classifying plant communities — a new way 8 Tree diseases — bane of aspen 12 New publications 15 Cover Aspen trees are popular and important to our western forests. They are also very susceptible to diseases. Scien¬ tists at the Rocky Mountain Station have been studying several aspen diseases since the 1960's, and have helped identify several of them. Read more about it on page 12. To Order Publications Single copies of publications referred to in this magazine are available without charge from the issuing station unless another source is indicated. When requesting a publication, give author, title and number. Each station compiles periodic lists of new publications. To get on the mailing list write to the director at each station. Subscriptions Subscriptions to this magazine will be sent at no charge. Write To: Forestry Research West 240 West Prospect Street Fort Collins, Colorado 80526 To change address, notify the magazine as early as possible. Send mailing label from this magazine and new address. Don’t forget to include your Zip Code. Permission to reprint articles is not required, but credit should be given to the Forest Service, U.S. DA Mention of commercial products is for information only. No endorsement by the U.S.D.A. is implied. A report for land managers on recent developments in forestry research at the four western Experiment Stations of the Forest Service, U.S. Department of Agriculture Western Forest Experiment Stations Pacific Northwest Forest and Range Experiment Station (PNW) 809 N.E. 6th Ave. Portland, Oregon 97232 Pacific Southwest Forest and Range Experiment Station (PSW) P.O. Box 245 Berkeley, California 94701 Intermountain Forestand Range Experiment Station (INT) 507 25th Street Ogden, Utah 84401 Rocky Mountain Forest and Range Experiment Station (RM), Drawer FRW 240 West Prospect Street Fort Collins, Colorado 80526 Prognosis: fortune-teller for forest stands by Delpha Noble Intermountain Station Prognoses — forecasts of a future course or development based on knowledge — today are playing an in¬ creasingly important role in forest planning. How will the forest respond to silvicultural practices such as re¬ generation harvests, site preparation, planting, thinning, weeding or pest control? Where should investments be made? Have past practices turned out as expected? Managers of public and private forest lands are obtaining answers to these and similar questions by using the Prognosis Model for Stand Develop¬ ment developed by researchers at the Intermountain Station's Forestry Sciences Laboratory, Moscow, Idaho. The model, a valuable tool for pro¬ ducing growth and yield tables, fore¬ casts stand development strategies by simulating the growth and mortality of individual tree samples. One large forest products company has reported a 35-percent increase in timber har¬ vest from their lands, based on the use of a collection of computer pro¬ grams produced by Forest Service re¬ search. Prognosis is a key element in that collection. One of the strengths of the model, says project leader Albert Stage, is that it is based on routine inventory data from forests where it is to be used. Therefore, it represents all con¬ ifer stands inventoried on forests in a specific geographic area. Equally im¬ portant, it has been shaped and re¬ fined in response to suggestions and evaluations by many critical users. Version 4 of the model, and the asso¬ ciated Users' Manual, were released at a workshop in Moscow, Idaho in July 1981, attended by over 90 for¬ esters. Senior author William Wykoff, Nicholas Crookston, and Stage be¬ lieve this version is a substantial im¬ provement over its predecessors and one that should be stable for a time. Because they see the modeling proc¬ ess as a means to coordinate, assim¬ ilate, and organize quantitative in¬ formation about ecosystems, the researchers believe continuing evolu¬ tion of the model is necessary and inevitable. Stage and the others developed the model explicitly for use in planning but they say it also may have re¬ search uses as well. According to Stage, models used for planning must be judged by different criteria than those representing scientific theory. Planning models require greater sta¬ tistical validity but may be based on less complete theoretical knowledge of the system than are hypothetical models. Because plans are always a statement about the future, however, Stage says a good planning model should be a combination of theory and empirical data. Multi-resource planning Prognoses can be produced for any forest inventory that samples trees and their characteristics. The full capabilities of the model, however, are realized when the sampling unit is a stand, or even better, clusters of stands, and when the tree character¬ istics include radial growth and crown length. By examining all the stands in a cluster, managers may analyze in¬ teractions among adjacent stands and among the proposed treatments. For example, it is possible to interpret the effects of timber harvesting on wildlife and pest populations that range across or infest more than one stand. When the cluster includes an entire watershed, the model forecasts changes in stand cover so that effects on streamflow can be deter¬ mined. For scheduling timber harvest, yield tables from classes of stands are compiled into composite yield tables. Results can be passed within the computer system to an economic analysis program designed by the University of Idaho to work directly with Prognosis. 1 The model may be used in conjunc¬ tion with watershed and wildlife habi¬ tat models. The Stand Prognosis Model provides estimates of the ver¬ tical and horizontal distributions of conifer crowns, shrub cover, and pro¬ duction of wildlife browse. These capabilities have been used in the research program for the Gospel- Hump area of the Nezperce National Forest. In this application, prognoses are linked with a sediment transport model, an ariadromous fishery model, and an elk and moose habitat model, all of which depend on the spatial pat¬ terns of treated areas. When the model is used with its sev¬ eral extensions to represent insect/ pest impacts, it comes closest to the common use of the term prognosis: “A prediction of the course or devel¬ opment of a disease.” Land man¬ agers concerned with pest infesta¬ tions have long needed a method to estimate benefits from selected man¬ agement practices. They have been stymied, however, by complex inter¬ actions between pest populations, the damage they cause, and the dynam¬ ics of stand development. Although Prognosis is not the first stand model used to analyze the impact of pests, it is one of the first to integrate a wide range of silvicultural practices with treatments of the pest population. As such, it can be a valuable tool for bringing pest management into the scope of silvicultural decisionmaking. The pest-dynamics extensions also demonstrate the value of modeling for coordinating the efforts of large teams of independent investigators. The Douglas-fir tussock moth exten¬ sion was the product of many people working in the Department of Agricul¬ ture’s Accelerated Douglas-fir Tus¬ sock Moth Research and Develop¬ ment Program. Robert Monserud, mensurationist at the Laboratory, linked the tussock moth dynamics model with the Stand Prognosis model. Similarly, Crookston's work portraying the effects of mountain pine beetle on lodgepole pine stands was partly a product of research sponsored by the International Biome Program at the intermountain Sta¬ tion, the University of Idaho, Washington State University, and University of California. Current work on the western spruce budworm ex¬ tension is sponsored by the CAN USA (Canada-United States) Spruce Bud- worm Program. How the model works The Stand Prognosis Model begins with a stand inventory describing the site (habitat type, slope, aspect, and elevation) and attributes of represent¬ ative sample trees. Current diameter and species must be recorded for the sample trees. Stage says it is highly desirable to record the length of live crowns and a sample of tree heights. If periodic growth is measured on two or more trees of a given species, the automatic calibration procedure will adjust the prediction equations to match the growth of the stand. The model first compiles the inventory and produces tables describing cur¬ rent stand conditions. Then, the first of one or more projection cycles (up to 40 cycles are possible) is begun. The number of years in a projection cycle is variable. Each projection cycle begins with the simulation of a silvicultural option (one option is ‘‘no treatment”). Next, periodic diameter growth, periodic height growth, and periodic mortality rates are computed for each inventoried tree. After tree attributes are updated and tree vol¬ umes are calculated, tables describ¬ ing the projected characteristics of the stand are prepared. Mechanical POLICY B POLICY C IMPOSE MANAGEMENT ACTIVITIES SUMMARIZE STAND ATTRIBUTES DISPLAY STAND j I INCREMENT TIME UPDATE TREE ATTRIBUTES WHAT TREES P . HOW FASTP DBHP HEIGHT? . T~ CROWN? ! y^T^iHEALTHY TREE r^TtL, PREDICT GROWTH fry PEST CONTROL OPTIONS: 'V? • BIOLOGICAL SPRAYS ■CHEMICAL SPRAYS 'M 7* DEDUCT NORMAL MORTALITY ESTIMATE PEST DAMAGE OUTBREAK ALTERS • PROBABILITY OF MORTALITY ■ PROBABILITY OF TOP- •DIAMETER AND HEIGHT GROWTH & TIMBER INTERESTS ENVIRONMENTALISTS ECONOMICS SPORTSMEN WHOOOP EEE / 2 site preparation, burning slash, plant¬ ing and other practices that follow harvest cuttings can be specified. Es¬ timates of the restocking that occur after these practices are based on Dennis Ferguson’s extensive sam¬ pling and analysis of managed stands in the grand fir-cedar-hemlock eco¬ system. The model displays the ef¬ fects of tree vigor on growth only to the extent that vigor can be described by the length of live crown. Further improvements would depend on add¬ ing measures of tree vigor, such as the one developed by Silviculturist Charles Wellner for white pine. (Mr. Wellner, now retired, is a former As¬ sistant Director of the Intermountain Station. Fie is an authority on the sil¬ viculture of Northern Rocky Mountain Forests.) As Researcher Russell Graham has shown, these tree vigor classes differ substantially in the like¬ lihood of mortality. What the mode! tells us about management Models represent the expected. Com¬ parisons between model-based fore¬ casts and their actual counterparts, therefore, emphasize the surprises — the as yet unpredictable workings of the ecosystem. When the scientists compared their model to records of stand development extending as long as 60 years, they determined that the estimates of individual tree growth were accurate. Most of the forecast¬ ing errors were the result of irregular mortality. Stage says that fact is not surprising, but “What is significant is the amount and variation of the mortality losses.” In Inland Empire forests, almost one third of the total productivity is lost to mortality. Although managed stands lose somewhat less, the magnitude of the losses emphasizes the need to plan for their utilization. Mensuration- ist Dave Flamilton has developed monitoring and analysis procedures, tailored to the inherent variability of mortality, that should be useful for locating and estimating losses. The researchers suggest, however, that rather than lamenting the problem, managers should include in their plans flexibility to adapt to the unpre¬ dictable but inevitable losses. This un¬ predictability should also influence the design of road and harvesting sys¬ tems and of systems for marketing the dying trees. “Finding ways to cap¬ ture these losses probably can do more to improve the total productivity of our forests than any other silvicul¬ tural treatment,” says Wellner. Accessing the model Models as comprehensive as Prog¬ nosis require a substantial computer to run them efficiently. Large forestry organizations with their own computer systems have obtained copies of the model and have procedures by which field foresters can enter stand inven¬ tories and compare management al¬ ternatives. For potential users without computers, inventory data can be sent to the University of Idaho or Uni¬ versity of Montana for processing. Ex¬ tension Foresters and the Forest Service branch of State and Private Forestry periodically conduct work¬ shops to show how these services can be obtained. At present the Inland Empire version, supported by the Intermountain Station, is the most widely used. Geographic variants, tailored to local biological conditions, are being developed by various groups of users for central Idaho, southwest and eastern Oregon, central Washington, eastern Montana, and western Wyoming. If you’re interested in reading indepth reports on the role of modeling in forest management, here are a few suggestions: Stage, Albert R., Richard K. Babcock, and William R Wykoff. 1980. Stand- oriented inventory and growth projec¬ tion methods improve harvest sched¬ uling on Bitterroot National Forest. “Journal of Forestry,” 78(5): 265-278. (Reprint I NT-680). Wykoff, W. R., N. L. Crookston, and Albert R. Stage. In press. User’s guide to the stand prognosis model. USDA Forest Service General Technical Report. Intermountain Forest and Range Experiment Station, Ogden, Utah. Stage, Albert R., and Dennis E. Fer¬ guson. In press. Regeneration mod¬ eling as a component of forest suc¬ cession simulation. In Proceedings, Symposium on Forest Succession and Stand Development Research in the Northwest (March 26, 1981, Corvallis, Oregon.) Hamilton, David A. 1981 . Large-scale color aerial photography as a tool in sampling for mortality rates. USDA Forest Service Research Paper INT-269, 8 p. Intermountain Forest and Range Experiment Station, Ogden, Utah. Stage, Albert R. 1978. Stand prog¬ nosis model — the central link in a decision-support system for forest managers. Proceedings, Society of American Foresters 1978: 256-257. Brookes, Martha H., R. W. Stark, and Robert W. Campbell, eds. Douglas-fir tussock moth: a synthesis. USDA For¬ est Service Technical Bulletin 1 585. Washington, D.C. Crookston, Nicholas L. 1978. Pre¬ dicting the outcome of management activities in mountain pine beetle susceptible lodgepole pine stands. Proceedings, Society of American Foresters 1978: 276-280. Graham, Russell T. White pine vigor — a new look. USDA Forest Service Research Paper. INT-254, 15 p. Intermountain Forestand Range Experiment Station, Ogden, Utah. Further information on Prognosis can be obtained by writing: USDA Forest Service Intermountain Forestand Range Experiment Station Forestry Sciences Laboratory 1221 S. Main St. Moscow, Idaho 84843 3 Timber harvesting and water quality in the Bull Run Municipal Watershed by Samuel T. Frear Pacific Northwest Station The Bull Run Municipal Watershed is a forested, often foggy, area of 95,000 acres in Oregon's Mount Hood National Forest that provides water to the City of Portland 30 miles to the west. Controversy has swirled about this area for many years. There has been public questioning about how the watershed, the major source of water for more than 800,000 people, should be managed. Scientists from the Pacific Northwest Station became involved back in 1955 when the Forest Service agreed with the City of Portland that more tech¬ nical information about the watershed was needed. The basic problem has been over water quality: can roads be built and timber removed without damaging the clean, pure water required by the citi¬ zens of Portland? The Pacific North¬ west Station's assignment: determine the effects of timber harvesting on the quantity and quality of water in the Fox Creek stream system of Bull Run. Fox Creek was selected for the study because it presented an opportunity to have three untouched and similar subdrainages for conducting experi¬ ments. One subdrainage was used as a control, while different management practices were applied in the other two. The Fox Creek sites are relatively gentle terrain. About 30 percent of the total Bull Run watershed is similar to them. The formal part of the research agreed to in 1 955 is now concluded. The research shows that timber har¬ vest can be done without causing sig¬ nificant impacts on the quantity and quality of water in those parts of the Bull Run which are like the study area. This research, combined with studies from other sites in the Oregon Cascades, provides managers with data upon which plans can proceed that will permit the Forest Service to conduct timber management in the drainage, while the City of Portland provides pure water to its citizens. In most respects Bull Run resembles drainages all along the western slopes of the Cascade Range in Ore¬ gon and Washington. It is covered with old-growth Douglas-fir and hem¬ lock and has many small streams de¬ scending to the valley below. Sunlight rarely reaches the forest floor; in the cool, dark forest there is much moss, lichen, and fern. The lower portions of Bull Run lie at 800 feet elevation; the upper parts at about 4,200 feet. The drainage slopes to the west where clouds that sweep in from the Pacific Ocean can be scooped up. Many clouds come into Bull Run: rainfall at the lower portions, measured since 1957, averages 106 inches annually, with 83 percent fall¬ ing from October to April. Rainfall in the upper reaches of Bull Run aver¬ ages 1 70 inches annually. 4 A Bull Run Watershed Task Group, appointed jointly by the Forest Service and the City of Portland, in Septem¬ ber, 1 980 made a report on water quality management in the area. This group reported of Forest Service research at the Fox Creek site: ‘‘In general, the results of this work in¬ dicated that timber harvest had little effect on the quality of the water resource”, suggesting, ‘‘that logging can be carried out on the watershed without adversely affecting the water quality.” Richard Fredriksen, research soil sci¬ entist with the Station’s Forestry Sci¬ ences Laboratory in Corvallis, Oregon, agrees. Ffe said that logging can cause little adverse effect on water quality if it has been carefully planned and executed. Fredriksen reached this conclusion from research conducted at several sites in western Oregon, including the Fox Creek drainage. The Fox Creek study includes three watersheds. Fox Creek 1 (FC 1) had road construction and cable logging. Fox Creek 2 (FC 2) was the control, with a road crossing it. Fox Creek 3 (FC 3) had a road and both cable and tractor logging was used. The slash was burned on FC 1 and left to rot on FC 3. An all-weather road was completed across FC 1 and 2 to the south boundary of FC 3 in August, 1 965. FC 1 and 3 also had short temporary spur roads. Timber was clearcut in FC 1 in four units of 7 to 1 0 acres each, and high lead logging was com¬ pleted in July, 1969. Logging residue was burned in the fall of 1 970. Log¬ ging took place in FC 3 over a three- year period in two units of 1 9 and 24 acres, starting in 1969 and ending in 1 972. No residues were burned in this watershed. Stream gages were placed at the base of the three watersheds by the City of Portland Water Bureau in 1 958 when the area was undisturbed. Auto¬ matic sampling devices filled five- gallon jugs with water to be tested for turbidity, nutrients, and other charac¬ teristics. Rain gages were set up for determining quantity and quality of precipitation. Both air and soil temperatures were monitored with re¬ cording thermometers (thermographs). Month after month, year after year, scientists and technicians tended these instruments: lugging in batteries to run the samplers, and lugging out bottles of water for chemical analysis in Corvallis. The recording instruments were read and recorded and revital¬ ized. The result was reams of data for analysis by scientists. The four important water quality parameters that can be studied for a forest drainage are turbidity, nutrient enrichment, temperature, and micro¬ bial content. The study of Fox Creek includes all except microbial content. Turbidity Turbidity, as measured by passing a beam of light through a water sample, usually results from suspended soil particles caused by erosion, some natural and some that originate from soils disturbed by road construction and logging. In western Oregon, land¬ slides are the principal process by which soil enters streams. The years of research have shown that turbidity usually can be avoided in Bull Run. Fredriksen says it is geologically a very stable piece of ground compared to other west-side drainage basins. Just how stable is shown by compar¬ ing Bull Run to other watersheds, for example, in the Mapleton District of the Siuslaw National Forest, the H.J. Andrews Experimental Forest and the Alder Creek area of the Willamette National Forest, Stequaleho Creek on the Olympic Peninsula in Washington, and the Coast Mountains in British Columbia. Compared to these, Bull Run has by far the lowest rate of landslide movement. The stability of Bull Run is further shown by research indicating that slumping earthflow terrain, the most susceptible for flowing into streams, makes up only 3.2 percent of the area (compared to 25.6 percent in the Pl.J. Andrews Forest just 50 miles away). The parent material in Bull Run is 97 percent basalt and andesite material which is able to support its own weight (and thus not likely to slide). A rain gage stands in the Fox Creek area of the Bull Run Watershed In the Mt. Hood Na¬ tional Forest. The gage requires constant at¬ tention to record its intake and prepare it for the next rainfall. i This is one of the clearcut units in Fox Creek A 1 . It was cable yarded and burned in 1971 ¥ This is the same Fox Creek unit in 1975. Nutrient Enrichment Nutrients entering streams following timber harvesting are increased be¬ cause trees no longer take them from the soil and they are flushed by rain into streams. Also affecting increased supply is the conversion of tree tissue to disposable slash and its decompo¬ sition releases nutrients. Fredriksen said that analysis before logging oc¬ curred in Fox Creek showed that con¬ centrations of nutrients from the Fox Creek watershed were much lower than concentrations from similar wa¬ tersheds. “We don’t know why,” he said. “But our best guess is the low temperature. The storage of elements in soils is very low, and the release of nutrients from the bedrock to streams is slow due to low temperature. It is not typical at all of the older volcanic soils such as those in the Willamette and Umpqua National Forests to the south.” After harvesting, nitrogen is mineral¬ ized in quantities exceeding vegeta¬ tion requirements and the ability of soils to store them. Thus, an increase in nitrate concentration in streams is usually expected after logging, and this happened at Fox Creek. Although nitrogen in the streams increased considerably, Fredriksen said it did not have an important affect on the quality and usefulness of water in the reservoirs. In time, vegetation growth in clearcut units will use the nitrogen and its production will become bal¬ anced again. An increase in phos¬ phorous concentration could lead to increased growth of algae in the reservoir, but this has not happened. 6 Water temperature Increased temperature of stream water frequently results from timber harvesting because the streams are opened to sunlight. The effect is mod¬ erated by dilution from cooler ground water entering streams and by shade from regrowth of vegetation beside streams. Larger streams and reser¬ voirs can reduce the stream temper¬ ature by mixing warmer water with cooler water or by stratifying water of different temperatures in layers. Timber harvesting can be accom¬ plished to minimize warming effects, such as by leaving shade producing vegetation. Streamflow In addition to studying the turbidity, nutrient enrichment, and water tem¬ perature at Fox Creek before and after logging, the researchers studied the quantity of water flowing from the drainage. Based on watershed studies in other parts of the Pacific North¬ west, the researchers expected that streamflow would increase following logging in watersheds FC 1 and 3 be¬ cause logging removes vegetation that uses soil water. But Dennis Harr, a research hydrologist in Corvallis, compared stream flow records among watersheds and found that water yields in the Fox Creek watersheds were not appreciably changed after logging. Analysis of streamflow for the Fox Creek watersheds indicated a small decrease in water yields instead of the expected increase of 4 to 6 inches (100 to 150 mm). This is con¬ trary to what had been found by stud¬ ies in other partially logged water¬ sheds. In addition, the number of low-flow days in the summer (days with flow below an arbitrary base level) increased during many post¬ logging years at Fox Creek. This sug¬ gests that summer flows have de¬ creased following logging, another unexpected result from Fox Creek, but the probable cause has been found: fog drip. Fog drip Changes in fog drip after logging ap¬ pear to explain the anomalous results of the Fox Creek streamflow study. Fog is common at the elevation of these watersheds, and field crews have frequently experienced rainfall in the forest during periods when no rain was collected in a gage in a nearby clearing. During a 40-week period, Harr found net precipitation under an old-growth Douglas-fir forest in Bull Run totaled 1 6.5 inches (387 mm) more than in adjacent clearcut areas. Making ad¬ justments, the scientist calculated that in a full year fog drip could have added 35 inches (882 mm) of water to total precipitation when a rain gage in a nearby open area measured 85 inches (2160 mm). Thus he concluded that logging removed a significant source of precipitation: fog intercep¬ tion and drip. This offsets the ex¬ pected increases in water yield that would result from timber harvest. The other streamflow anomaly at Fox Creek — the increased number of “low flow” days — is probably also ex¬ plained by fog drip. The relative amount of fog drip was greatest dur¬ ing the summer so that when forest stands were cut as much as a third of precipitation could be eliminated. Accurate assessment of logging im¬ pacts on fog drip and water yield will depend not only on the long-term management plan for the Bull Run Municipal Watershed but also on the nature of fog drip. Harr emphasized that additional information on the areal distribution of fog drip and the size at which young trees catch sig¬ nificant amounts of fog is needed before the long-term impact of logging on water supplies can be determined. If you would like more information about this research, write to the Pa¬ cific Northwest Station and request Streamflow after Patch Logging in Small Drainages Within the Bull Run Municipal Watershed, Oregon, Re¬ search Paper PNW-268, by R. Dennis Harr. 7 Classifying plant communities— a new way by Marcia Wood Pacific Southwest Station This river ecosystem includes elements of both the Graminoid and Aquatic Subformations. 8 “Any time people from different pro¬ fessions try to work together on any sort of plan that involves wildland vegetation, there are bound to be problems about how to describe and classify the vegetation. A botanist, trained in classifying communities of wildland plants according to one method, may need to talk about this vegetation with a forester. If the for¬ ester is used to working with an en¬ tirely different classification system, there's going to be seme confusion and frustration!” These are the opinions of Research Forester Tim Paysen of the Pacific Southwest Station in Riverside, California. “In this State, you can choose from at least 20 different sys¬ tems for classifying communities of wildland plants,” he says. “This diver¬ sity makes it hard for people to work together well.” The new approach Known simply as “A Vegetation Clas¬ sification System for California,” the new classification scheme applies to any and all wildland vegetation in the State. Paysen and four collaborators have already shown how the System can be used to classify all southern California vegetation (see A Vegeta¬ tion Classification System Applied to Southern California, General Tech¬ nical Report PSW-45). Here’s how the Classification System works: The System has five "levels”. The “Formation” is the broadest, most general category. Following the “For¬ mation,” the categories become more and more specific. These other cate¬ gories are the “Subformation,” “Series,” “Association,” and “Phase.” In an attempt to resolve this problem, Paysen and colleagues from several other wildland management agencies developed yet another classification system. Theirs takes a different ap¬ proach from systems that were de¬ signed with just one specialized use — such as timber management or range management — in mind. “Our intent is to meet the combined needs of the ecologist, the botanist, the for¬ ester, the range manager, the wildlife biologist, and other people in natural resources management. Our system should solve the communication prob¬ lem, with a minimum of inconven¬ ience to any of these disciplines or to any wildland management agency.” Some examples: The Closed Forest Formation describes stands where overstory crowns of pines, firs, or other trees make up more than 60 percent of the total crown cover. The Woodland Formation is more open. It can include conifers, hardwoods, or — in the case of southern California vegetation — large succulents such as palms or Joshua trees. T rees in this Woodland Formation are more widely spaced than those in the Closed For¬ est Formation. The crowns of the Woodland Formation trees make up between 25 and 59 percent of the total crown cover. ■Ml Tim Paysen and Serena Hunter have classi¬ fied this community as belonging to the Kellogg Oak Series, and are now writing a more detailed description of the stand. Other Formations Brush species and cacti are among the dominant species in the Shrub Formation. Flere, shrubs make up more than 25 percent of the crown cover, and grow to be at least 1 -1 12 feet (45 cm)tall. Plant communities dominated by shrubs that never reach this height would fit into another category — the Dwarf Shrub Formation. What about grasslands? These are part of the Herbaceous Formation. In it, the dominant plants are grasses and herbs. Shrubs or trees provide less than 25 percent of the crown cover. “Subformations” defined “Each Formation is an aggregation of plant communities that are similar in structure or appearance,” Paysen says. These component communities are called Subformations. All of the dominant overstory plant species in a given Subformation have similarly shaped stems and leaves. In the Con¬ ifer Forest Subformation, for example, the dominant overstory species have either the needle-like leaves of pines and firs, the scale-like leaves of red¬ wood or cypress, or the awl-shaped leaves of giant sequoia. The Conifer Forest Subformation is part of the Closed Forest Formation. In line with the definition of the Closed Forest Formation, the canopy of the Conifer Forest Subformation makes up at least 60 percent of the total crown cover. But what if the conifers aren’t as dense, and take up less than 60 per¬ cent of the crown cover? In southern California, this is often true of digger pine, pinyon pine, and juniper. If these trees make up between 25 to 59 per¬ cent of the total crown cover, the cover. Open stands of California buck¬ eye, cottonwood, mesquite, blue oak, sycamore, and willow, for example, would probably be part of the Broad- leaf Woodland Subformation of the Woodland Formation — if the crowns of these trees make up between 25 and 59 percent of the crown cover. Dense stands of aspen, alder, Califor¬ nia bay, bigleaf maple, tanoak, or madrone would probably be classified as part of the Broadleaf Forest Sub¬ formation of the Closed Forest Forma¬ tion, if crowns of these trees provided more than 60 percent crown cover. The “Associations” Each of the Subformations is further described by the Series and Associa¬ tions that it contains. The Series is a collection of Associations. Each Asso¬ ciation within a Series has the same dominant overstory species. community meets the definition of a Conifer Woodland Subformation. This Subformation is, in turn, part of the Woodland Formation. This aspect of the System may take a little getting used to, because most people are accustomed to thinking of “woodlands” as forests of hard¬ woods — oak, madrone, and similar species. The trick is to remember that “Woodland” refers only to the density of the canopy. It indicates that the community is more open than the Closed Forest Formation. A “Wood¬ land” isn’t limited just to hard¬ woods — it can be made up of con¬ ifers, or even succulents. Hardwoods, or broadleaved trees, can belong to either the Closed Forest or the Woodland Formation, again de¬ pending on the density of the crown An example: the Coulter Pine Series is one of some 1 7 different series that make up the Conifer Forest Subforma¬ tion in southern California. Coulter pine is the dominant species in the Series. What Associations could make up the Coulter Pine Series? One example would be a plant community in which Coulter pine was the dominant over¬ story species, interior live oak was the dominant in the midstory, and ceano- thus was dominant in the shrub layer. This plant community would be called a Coulter Pine/Interior Live Oak/ Ceanothus Association. What if the vegetation were some¬ what different — Coulter pine still the dominant, but no live oak midstory, and manzanita — not ceanothus — as the dominant shrub? Then the vegeta¬ tion would be labelled a Coulter Pin el Manzanita Association. Both this As¬ sociation and the one with live oak and ceanothus would belong in the Coulter Pine Series, because Coulter pine is dominant in both cases. “Phases” explained Finally, the Phase. “The purpose of the Phase category is to give users a chance to plug in additional descrip¬ tions,” Paysen says. Fie suggests categories of Phases in the Southern California Vegetation Classification report. For example, a forester may need some further description of the Coulter Pine/Interior Live Oak/Ceano- thus Association, such as the diam¬ eter breast height of the pines. Following the Southern California guidelines, the designation Coulter Pine/Interior Live Oak/Ceanothus Association, Phase 2, could be used to describe stands where the pines average 1 to 5 inches in diameter. Or, let’s say that a fuels management specialist — someone concerned about the amount of flammable natural-fuels that accumulate in the forest — wants to know more about the ceanothus, a plant that can burn easily during the dry months. A Phase could be used to indicate the density of the ceanothus. "Phases can describe almost any major characteristic of the plant com¬ munity,” according to Paysen. “Phases are optional — they can be This community was classified as a Desert Mountain Mahogany/Sagebrush Association of the Chaparral Subformation, Shrub Formation. In addition to on-the-ground evaluations : aerial photography is used to locate and de¬ fine Associations, Series, and Phases. Here, Mary Hotchkiss uses aerial photography to check the distribution of a Series. added, if needed, or left out, if not. They can be used at any level of the hierarchy, not just at the Association level.” Adaptability The System is specific enough — especially at the Series and Associa¬ tion levels of the hierarchy — to accu¬ rately describe the vegetation on small, local sites. But, it is also gen¬ eral enough — in the Formation and Subformation, for example — to use on a much larger scale. The System is compatible with one that scientists at the Rocky Mountain Station in Fort Collins, Colorado, are developing for nationwide use by the Forest Service. It can also be used in conjunction with the international system for classifying vegetation that was developed for the United Nations Scientific, Educational, and Cultural Organization. 10 Other systems The System’s developers made an ex¬ tensive review of other major classifi¬ cation systems before coming out with their product. Among the sys¬ tems they studied included those developed by Browne and Lowe; Cheatham and Haller; Driscoll, Russell, and Meier; Kuchler; Mueller- Domboisand Ellenberg; Munz; Thorne; and Wieslander. The System closely follows the suggestions of Soil Scientist Andy Leven and Botanist Ed Horton, both of the Forest Service’s Pacific Southwest Region (National Forests of California). Foresters, ecologists, biologists, and range scientists all had a hand in de¬ veloping and critiquing the System. Representatives of Southern California Edison Company, the California State Department of Fish and Game, the Pacific Southwest Region of the Forest Service, the Fish and Wildlife Service, and the Bureau of Land Man¬ agement were among the agencies consulted as the System progressed. Current users Among the National Forests in Cali¬ fornia using the Classification System is the San Bernardino. Forest Botanist Jeanine Derby, who helped develop the System, says some 800,000 acres — the entire Forest and some private lands within the Forest — have been classified to the Series level. “This information has been used on several projects,’’ Derby reports. “On some grazing lands within the Forest, the Series designation indicates how often the vegetation — which in this case is shrubs — should be burned, to keep the preferred species of plants dominant, and to prevent the stands from becoming decadent.” The System presents a framework that can be used anywhere, as shown by the fact that the State Division of Forestry and Wildlife in Hawaii is using it. “The System is designed so that it can be applied to any vegeta¬ tion, whether that vegetation has ever been seen by the original developers of the System or not,” says Research Forester Serena Hunter of the Pacific Southwest Station. Hunter has worked with Paysen in explaining the System to prospective users. Her perspective; “An Interior Live Oak/Manzanita/ Needlegrass Association should mean the same thing to every agency or other group that is using the System. The results of classifying a plant com¬ munity to one or all of the hierarchical levels of the System should be similar — within an acceptable degree of tolerance — no matter who is doing the classifying.” The silver cholla cactus is a dominant understory species in the Desert Apricot i Mojave Yucca/Silver Cholla Association Forestry Research West readers who would like more information are wel¬ come to call Tim Paysen at the Forest Fire Laboratory (714) 351-6552 (FTS: 796-6552) or to write him at the Labo¬ ratory, 4955 Canyon Crest Drive, Riverside, California 92517. 1 1 Tree diseases— bane of aspen by Rick Fletcher Rocky Mountain Station 12 Quaking aspen is one of the most popular and widespread tree species of western mountains. Trees can live to be 200 years old and obtain heights of 1 00 feet or more. Aspen are esthetically important around campgrounds and other developed areas, are a favored habitat for a variety of wildlife, an&have recently been recognized as valuable by the timber and pulpwood industries. The diseases Scientists with the Rocky Mountain Station’s Forest Diseases in the Rocky Mountains and Southwest unit at Fort Collins, Colorado, have been studying aspen diseases since the 1960’s. They have helped identify several of them. The following is a look at some of the most common canker diseases: Despite its amenities, aspen has one major drawback — its high susceptibil¬ ity to diseases. The bark is a thin, soft, living part of the tree, and a poor protector against wounds, insects, and diseases. Of all aspen diseases, cankers are by far the most serious cause of tree death. A survey of 5 na¬ tional forests in Colorado showed 1 1 percent of all aspen trees had one or more types of cankers. Similar situa¬ tions exist in aspen stands throughout the West, including Alaska, Canada, and parts of Mexico. A canker is a lesion, usually on the trunk , caused by a fungus entering through a tear or puncture in the bark. Scientists believe that the in¬ vading fungus produces a toxin which results in cell death, bark collapse, and localized death of the living tissue. With time, the canker spreads. If cankers girdle the trunk, nutrient flow is cut off, resulting in tree mortality. Sooty-bark canker, caused by the fungus Cenangium singulare, is the most lethal canker of western aspen. Frank Hawksworth, Research Plant Pathologist and Project Leader for the Fort Collins unit says, ‘‘Upon pene¬ trating the inner bark and cambium, it spreads rapidly — up to 40 inches per year — and can result in cankers 12 feet long in just 4 years time.” Trees of ali sizes are killed, usually in 3 to 1 0 years. As the tree succumbs, the dead bark crumbles to a sooty-bark residue — hence the name sooty-bark canker. This disease is found mainly on larger trees older than 60 years of age in the middle elevation range of aspen. Black canker is another common enemy of aspen. It is plentiful in local¬ ized areas where up to 50 to 65 per¬ cent of the trees can be infected. During a 12-year period, almost 70 percent of the aspen in this once heavily forested camp¬ ground succumbed to diseases. Research Plant Pathologist Thomas Hinds, also with the disease project, and one who has spent many years studying aspen diseases, says, “Be¬ cause tree circumference growth usu¬ ally outpaces black canker growth, single cankers seldom kill a large tree unless two or more combine to girdle the trunk.” Black canker, however, does cause trunk deformity and brown stain and wet wood extending into the heart- wood. Crytosphaeria is the newcomer to the list of aspen cankers. Although the fungus Cryptosphaeria populina has been known to exist tor some time, it was just recently related to canker formation. Since its discovery, it has been found from Mexico northward throughout the Rockies to Canada and into Alaska. The cankers, usually associated with trunk wounds, are long and narrow. Small trees often die within two years, even when not girdled. Large trees may survive longer. The infected bark around the canker is light brown to orange. As the bark dies, it becomes black and sooty-like, similar to sooty- bark. However, it is easy to distin¬ guish as the dead bark contains small, light-colored areas from 0.5 to 2.0 mm in size. The most common fungus found on aspen, Cytospora chrysosperma, causes Cytospora cankers. This fungus readily enters bark that has been injured or weakened, even through dead and dying twigs. Trunk cankers form a dark brown to black circular pattern. Dead bark re¬ mains attached to the tree for 2 or 3 years. It then turns light brown and falls off in large pieces. Although the fungus may be active in the bark, cankers are usually slow to form. Fruiting bodies of the fungus are often evidenced, however, by long, coiled, orange to dark red masses called spore tendrils, spore horns, or cirri on the dead outer bark. A Cenangium canker girdled and killed this aspen in six years. The wound was caused during a logging operation. The fungus, called Ceratocystis fim- briata, invades the inner bark and cambium during the tree’s dormant season, and kills a portion of the tissue. This process is repeated year after year, forming a black-target¬ shaped canker. Large healthy trees often outgrow Cytospora cankers. Hypoxylon canker is less important to western aspen than the ones covered so far. Caused by the fungus Hypo¬ xylon mammatum, it is, however, the most damaging in the Lake States Re¬ gion, and occurs in aspen stands throughout the eastern United States. Diseased bark is mottled black and yellowish-white. About a year after in¬ fection, the fungus produces pillar-like structures that cause blistered areas in the center of the canker. Infected trees often die before they are completely girdled. Low density, mixed, and thinned stands tend to have more infection, as do trees on the edges of stands, rather than within. Although not a canker disease, “droopy aspen”, is an unusual dis¬ order that has appeared in recent years damaging ornamental trees in mountain communities, and to a lesser extent, in natural forest stands. The twigs become elongated and rub¬ bery, and the affected trees droop like a weeping willow. The malady causes premature death. Studies are being conducted in cooperation with the Department of Botany and Plant Pa¬ thology at Colorado State University to determine the cause of this condi¬ tion and a basis for developing control measures. Other aspen cankers are known, but are not as widespread, and are con¬ sidered less of a problem than those listed here. Control methods Although no chemical control meas¬ ures are known for aspen cankers, silvicultural controls have met with some success. 13 Removal of cankered trees will help eliminate the disease source and pro¬ vide additional space for healthy trees. Aspen stands should not be opened up too quickly, however, because they are sensitive to sun- scald and the stand could rapidly deteriorate. Since canker diseases usually in¬ crease with stand age, managing aspen in small uneven-aged groups on a rotation of 80 to 1 00 years is suggested. If a stand is heavily infected, clear- cutting or prescribed burning may be the best alternative. “In fact,” says Hinds, “we are suggesting that clear- cutting may be the best management strategy for aspen, whether the stand is diseased or not. Since the bark is so susceptible to wounds, it is difficult and costly to thin diseased trees with¬ These Ceratocystis cankers are about 12 years old and probably began from camper caused wounds. Notice the carvings In the bark. out damage to the healthy ones. And, once the bark on healthy trees is wounded, it opens the door to fungus infection and you are back to a diseased stand again within a few years. Whereas, clearcutting will not only allow aspen to resprout and pro¬ duce a vigorous new stand, but will reduce the disease impact and avoid a change in the stand to mixed or less desirable tree species.” If especially high-value trees (such as in campgrounds or in urban settings) develop cankers, it is possible in the early stages of infection to cut out the fungus. All infected bark, wood, and healthy tissue within two inches of the canker, must be cut away using ster¬ ile tools. The exposed wood should then be covered with a tree wound dressing. Through continued research and proper management, we can rest as¬ sured that aspen and all its benefits will be around for a long time to come. For further reading, the following pub¬ lications are available from the Rocky Mountain Station (see the inside front cover for the address). Hinds, Thomas E. and Eugene M. Wengert. 1977. Growth and Decay Losses in Colorado Aspen. USDA For¬ est Service Research Paper RM-193. Juzwik, J., W. T. Nishijima and Thomas E. Hinds. 1978. Survey of Aspen Cankers in Colorado. A reprint from Plant Disease Reporter, Vol. 62, No. 10. Hinds, Thomas E. and Thomas H. Laurent. 1978. Common Aspen Diseases Found in Alaska. A reprint from Plant Disease Reporter, Vol. 62, No. 11. Hinds, Thomas E. 1976. Aspen Mor¬ tality in Rocky Mountain Camp¬ grounds. USDA Forest Service Re¬ search Paper RM-164. Hinds, Thomas E. 1981 . Cryptosphae- ria Canker and Libertella Decay of Aspen. A reprint from Phytopathology , Vol. 71, No. 11. Droopy aspen is especially prevalent in aspen planted for landscaping purposes. It has also shown up in natural stands, however New publications To Order Publications Single copies of publications referred to in this magazine are available without charge from the issuing station unless another source is in¬ dicated. When requesting a publica¬ tion, give author, title and number. Analyzing residues in Pacific Northwest forests There is increasing interest in the Pacific Northwest in the millions of tons of residues remaining in the forest after logging: Can it be used to generate energy? Is it a valuable source of material needed by the pulp and particle board industry? Two reports by James Howard of the Pacific Northwest Station provide improved means of analyzing forest residues. The first presents the characteristics of residue material in Oregon, Wash¬ ington, and Idaho that affects its potential use for energy and other products. Data collected from meas¬ urements on 518 plots in the three states provides volumes by diameter and length, number of pieces per acre, percent of residue that is sound, average percentage of bark, and ac¬ cessibility by slope and distance to road. The second report describes a method to estimate the amount of logging residue in an area, using ratios which relate the quantity of residue to the volume of timber or number of acres harvested. Copies of Logging Residue in the Pacific Northwest: Characteristics Af¬ fecting Utilization, Research Paper PNW 289, and Ratios for Estimating Logging Residue in the Pacific North¬ west, Research Paper 288, both by James O. Howard, are available from the Pacific Northwest Station. Managing and rehabilitating the backcountry As recreational use of backcountry areas continues to increase dramati¬ cally, land managers are concerned with maintaining the quality of this re¬ source. This is particularly true for areas in the National Wilderness Pres¬ ervation System and the backcountry of National Parks where a major goal is to preserve “natural conditions.” To deal effectively with the problem of human disturbance in these areas, managers must understand ecological processes and the relationship be¬ tween visitor use and impact. They must also be aware of practical methods of managing users and re¬ habilitating excessively damaged sites. A report issued by the Intermountain Station can help managers meet these needs. David N. Cole and Ed¬ ward Schreiner have compiled an in¬ terpretive bibliography on backcountry impacts, management, and rehabili¬ tation. The report, containing 300 references, is primarily concerned with recreational impacts on the soils and vegetation of backcountry areas and how to rehabilitate sites that have received excessive impact. Write to the Intermountain Station for a copy of Impacts of Backcountry Recreation:. Site Management and Rehabilitation, INT-GTR-121, FR 29. 15 Behavior of phenoxy herbicides and TCDD summarized Scientists are not able to resolve the emotional and philosophic elements of the public controversy about herbi¬ cide use in forests, however, they continue to compile technical data to assist in the continuing debate. Logan Norris of the Pacific Northwest Station has written an extensive re¬ view of the technical literature on the movement, persistence, and fate of phenoxy herbicides and TCDD in the forest. Both phenoxy herbicides and TCDD (the highly toxic contaminant of 2,4,5-T and Silvex) are discussed in relation to their behavior in the forest environment and their bioaccumula- tion in animals. Risk is the predominant technical issue in the controversy about use of herbicides in the forest. Scientists be¬ lieve more data is needed so forest managers can make better assess¬ ments of risk. Information is particu¬ larly limited on the effects of phenoxy herbicides and TCDD on air and streams. Copies of The movement, persistence, and fate of the phenoxy herbicides and TCDD in the forest, from “Resi¬ dues Review”, Volume 80, by Logan A. Norris, may be obtained from the Pacific Northwest Station Cost/benefits of fire management activities To ensure that fire management pro¬ grams are cost effective and respon¬ sive, fire managers and planners have to be able to compare costs and benefits. Changes in fire protection programs can cause changes in the number, size, or severity of wildfires. Is the change in program cost consis¬ tent with the change in net losses due to wildfire? Changes in fire use pro¬ grams also are to be cost effective and responsive. Does a prescription fire create enough net benefits to jus¬ tify its cost9 To answer such questions as accu¬ rately as possible, managers require good estimates of the costs, losses, and benefits associated with both wildfires and prescription fires. These three factors vary a great deal de¬ pending on size, intensity, fire loca¬ tion, fuel, weather conditions, and many other circumstances. The Intermountain Station has pub¬ lished a guidebook containing fire val¬ uation procedures that provide an estimate of fire costs, losses, and benefits. The procedures call for post¬ fire examination of each class C and larger wildfire and each prescription fire, leading to a summary of costs, losses, and benefits for each. The procedures are included in Fire Costs, Losses, and Benefits: an Economic Procedure, General Technical Report INT-108-FR 29, by Robert J. Marty and Richard J Barney. Although the procedures were developed primarily for Forest Service use, they are adaptable to other agency and individ¬ ual situations. Write to the Intermountain Station for a copy. 16 “SCAN IT”— new aid for processing map and photo data A new series of computer programs, called “SCANIT’’, can be used to prepare data from maps and photos for later processing through comput¬ erized land-information systems. SCANIT was designed to be used with systems like the RID* POLY Geographic Information System RID*POLY tabulates and stores such information as acreages of various soil or timber types on a given Na¬ tional Forest. The SCANIT programs are used with an automated scanner to convert in¬ formation from maps and photos into digits that can be read by computer. SCANIT can also be used to check and edit this information before it goes to the computer for analysis. Other uses of SCANIT, and informa¬ tion about the equipment required, are described in SCANIT: Centralized Digitizing of Forest Resource Maps or Photographs , General Technical Report PSW-53, by Research Forester Elliot L. Amidon and Computer Systems Analyst E. Joyce Dye of the Pacific Southwest Station. Instructions on how to use each of the SCANIT options are included in the Report: copies are available from the Pacific Southwest Station. Prospective users who would like SCANIT programs copied onto mag¬ netic tape should write Joyce Dye at the Pacific Southwest Station in Berkeley for further information, or should phone her at (4 15) 486-31 27 (FTS: 449-3127). Using a computer to estimate yarding costs A program designed for a pocket computer that will enable logging operators and planners to save time and money is described in an article by Ronald Mifflin of the Pacific North¬ west Station. Mifflin gives the step-by-step proce¬ dure to use basic costs and produc¬ tion values to rapidly figure the cost of a yarding operation. The impact of cost or production changes can be quickly pinpointed, and the econom¬ ics of alternative yarding systems compared. Machine rate is the hourly cost of owning and operating equipment. Pro¬ duction rate is the volume of timber brought to the landing per unit of time These, along with the costs of moving the yarder and rigging the lines and the cost of moving equip¬ ment in and out, can be expressed in a formula to determine yarding cost. The program is designed for use in a Hewlett-Packard 97, 67, or 41 C cal¬ culator and is adaptable to other pro¬ grammable calculators. Copies of Estimating Yarding Costs by Computer , in the “BC Lumberman,” July, 1981, by Ronald Mifflin, are available from the Pacific Northwest Station. 17 Forest fuels— gauging how much is on the ground The jumble of cones and needles, small branches and twigs, broken limbs, and decaying trees on a forest floor is natural fuel for wildfires. In most stands, as the amount of this debris builds up, so does the fire hazard. This is why two northern Californians have prepared a field guide for estimating how much natural fuel is on the ground in a given forest. Fuels management specialists can use this information to develop strategies for handling these hazardous accumula¬ tions of flammable fuels. The new handbook applies to stands of ponderosa pine, lodgepole pine, white fir, red fir, mountain hemlock, or mixed conifers in the southern Cas¬ cades and northern Sierra Nevada of California. Authors Ken Blonski of the Plumas National Forest and John Schramel, formerly of the Plumas, say the 145-page publication presents a “fast, easy, and inexpensive way to quantify forest residues." A series of color photos show typical accumulations of fuels in 56 repre¬ sentative stands. Each photo is ac¬ companied by a data sheet, which gives detailed information about the stand and about the amounts of resi¬ dues that could occur on the site. The reader needs only to find the photo that matches the conditions on a given area. The data sheets give the weight (in tons) and the volume (in cubic feet) for fuels ranging in size from less than one-fourth inch in diameter to 20 inches or more in diameter. Although the handbook is intended primarily for use in fuels manage¬ ment, Blonski and Schramel say the guide should also be an aid in plan¬ ning timber sales, in developing wil¬ derness management plans, and in evaluating accumulated fuels as a possible source of energy. They pat¬ terned the photo guide after the ap¬ proach developed by researchers Wayne Maxwell and Franklin Ward of the Pacific Northwest Station. For copies of the northern California handbook, write to the Pacific South¬ west Station. Berkeley, for General Technical Report PSW-56, Photo Series for Quantifying Natural Forest Residues: Southern Cascades, North¬ ern Sierra Nevada. 18 Managing blowing snow Three case studies on the design and performance of snow retention, snow fencing, and snow harvesting treat¬ ments are discussed in a new publi¬ cation by two authors from the Rocky Mountain Station. The study on snow retention explains how strips of crested wheatgrass planted on low-growing, sagebrush rangeland doubled snow accumula¬ tion compared to untreated rangeland. The strips were 3 meters wide and oriented with their long axis perpen¬ dicular to prevailing wind direction. The snow fencing study describes how a snow fence 3.05 meters in height was constructed along the windward side of a stream channel that led to an irrigation reservoir. Without the snow fence, natural snow storage in the channel would have been 27 cubic meters of water per meter of channel length. After fence construction, actual storage was 81 cubic meters of water per meter of channel length, an increase in water storage of 54 cubic meters per meter of channel. The third study describes a treatment in which sagebrush was removed from the windward side of a ridge. This allowed the wind to move snow to the leeward side of the ridge where it accumulated in a large drift. The treatment increased the transport of water contained in snow by 24 cubic meters per meter of ridge length. The report, written by David L. Sturges and Ronald D. Tabler, is ti¬ tled, Management of blowing snow on sagebrush rangelands. It is available from the Rocky Mountain Station (mailing address on inside front cover). New techniques to determine age of quaking aspen Methods for determining the age of trees range from the simple to the complex and entail approaches as diverse as using oil, chemicals, and hot black coffee. Determining the age of some trees such as quaking aspen, however, is more difficult. Most re¬ searchers view specimens of these trees through dissecting or regular microscopes. They consider labora¬ tory analysis essential for accuracy. The diffuse-porous wood of quaking aspen ( Populus tremuloides Michx.) makes the annual rings difficult to distinguish, even with complicated procedures. A biological technician at the Intermountain Station, however, has adapted a technique that is sim¬ ple, requires little specialized equip¬ ment, and in most cases yields satis¬ factory results. The technique, described in a recent Station publication, is used to analyze a shaved translucent increment core with simultaneous direct and reflected flourescent lighting to discern rings. The 5-page report tells how proper field procedures, such as boring the correct side of the aspen tree, record¬ ing the core height, and avoiding heart rot, can improve the accuracy of the ages obtained. The report is entitled Field and Labo¬ ratory Methods for Age Determination of Quaking Aspen, by Robert B. Campbell, Jr. For a copy, write to the Intermountain Station and request Re¬ search Note INT-314-FR 29. 19 Aspen classification on the Bridger-Teton Intensive multiple use management of our wildlands requires knowledge of the diverse resources, their potential productivity, and their likely response to management. This is especially true in the mountainous West where abrupt changes in environment create both striking and subtle differences in the land's capability to produce vege¬ tation. One way to acquire knowledge about vegetation resources is to cate¬ gorize land units. Approaches include habitat types, cover type, and com¬ munity type classification systems. Parts of the vegetation complex on the Bridger-Teton National Forest in Wyoming have been classified, but a detailed natural classification for the important aspen lands has been lack¬ ing. The scattered aspen groves are esthetically pleasing, highly valued multiple use areas, providing good watershed protection, abundant live¬ stock forage, and habitat for many forms of wildlife. The aspens’ importance prompted a cooperative effort between the Forest and the Intermountain Station that has culminated in a new publication de¬ tailing 26 aspen community types. Authors Andrew P. Youngblood, plant ecologist on the Bridger-Teton, and Walter F. Mueggler, leader of the Sta¬ tion's Aspen Ecology research work unit, provide a diagnostic key that uses indicator plant species for field identification of the community types. The scientists discuss vegetation composition, environment, productiv¬ ity, relationship to surrounding vegeta¬ tion, and successional status. Tables and photographs illustrate many of the 26 types. Youngblood and Mueggler point out that community type classification has several benefits for the resource man¬ ager. It communicates ideas about similar vegetation and environments, suggesting that such sites might re¬ spond to similar management actions. The community type classification, when coupled with other systems, provides management with realistic alternatives for resource use. For your copy of Aspen Community Types on the Bridger-Teton National Forest in Western Wyoming, write to the Intermountain Station and request Research Paper INT-272-FR 29. U S GOVERNMENT PRINTING OFFICE 1982 — 578-683/232 Rainfall on snowpack in western Oregon Rainfall on snowpacks, a common occurrence between 1,200 and 3,600 feet elevations in Western Oregon, has been a dominant factor causing landslides and depositing large amounts of sediment and debris in streams. This, in turn, may drastically affect the stream and its impact on low-lying areas. Sometimes the result of this phenom¬ enon has been large scale flooding of urbanized areas such as in 1964, 1965, and 1974 when millions of dollars in damage was caused in the Willamette Valley of Oregon by warm rain falling on snowpacks. Snowpacks in Western Oregon are “warm” — they have interior tempera¬ tures at or near 0 degrees C so that little energy is required to initiate melting. A warm pack can yield water quickly during a period of high air temperature and rainfall. Researchers are concerned about whether clearcut logging exacerbates potential landslides and flooding when all other conditions of snow, warm air, and heavy rains are right. It is pos¬ sible that clearcuts could increase water input to soil by 10 to 25 percent where packs are shallow. Without additional studies, however, it cannot be said with certainty that clearcutting does or does not affect rate of snowpack melt during rainfall. In light of the possible consequences of increasing melt by timber harvest, a strong argument is presented for more study of this phenomenon. Copies of Some Characteristics and Consequences of Snowmelt during Rainfall in Western Oregon, in “Jour¬ nal of Hydrology” 53(1981), by R.D. Harr is available from the Pacific Northwest Station. Don’t miss the next issue. You’ll read about the latest in fire economics research; learn the importance of birds and ants as predators of the western spruce budworm; and dis¬ cover a computer tool for surface mine reclamation planning, called SEAMPLAN. You’ll also have a chance to review several new re¬ search publications. WATCH FOR IT! If you know of someone who would be interested in this publication, he or she can be added to the mailing list by filling out the coupon below and mailing it to us. Please add my name to the mailing list for Forestry Research West. Mail to: Forestry Research West U.S. Department of Agriculture Forest Service 240 West Prospect Street Fort Collins, Colorado 80526 £ o ^ ? Q) O 03 ° C ^ Co ? 3' Co QJ Co CD C Co CD V9 Oo o o ~n I\3 ~n C n o O o CO O O $ 5 CO o 33 m o_ 5* CD c n CO 0 0 TO 0 H tn T) < 3D O o O CO T3 o’ 0 3 0 13 -< 33 o CD m 3 O O V) Q. O oo CO 5 > CO m > 3D o cn 0 o’ O IV) c I 03 ET m c/>