Historic, Archive Document Do not assume content reflects current scientific knowledge, policies, or practices. * w/ . jrestry Research West j. Forest Service U.S. Department of Agriculture September 1981 Forestry Research West Forest Service U.S. Department of Agriculture September 1981 In This Issue page Researchers evaluate insecticides 1 Old-growth forests 6 Learning to manage southwestern riparian ecosystems 1 1 Research on the desert 14 New Publications 17 Cover Scientists at the Pacific Southwest Station are working to find better ways of managing destructive forest insects without harming other beneficial organisms. To help with these studies, Biological Technician Lucille Boelter supervises the rearing of a laboratory colony of western spruce budworms. The cups contain larvae and cubes of artificial diet. Read more about it on page 1 . (Photo by Dennis Galloway) 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.D.A. 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 Forest and Range Experiment Station (NT) 507 25th Street Ogden, Utah 84401 Rocky Mountain Forest and Range Experiment Station (RM) 240 West Prospect Street Fort Collins, Colorado 80526 Researchers evaluate insecticides by Marcia Wood Pacific Southwest Station Chemical insecticides that are used in forests should control destructive insects without harming other forest life. This is the standard that re¬ searchers in the Pacific Southwest Station's Insecticide Evaluation Proj¬ ect follow in assessing insecticides that are proposed for use in forests. According to Research Entomologist Michael I. Haverty, who is leader of the Insecticide Evaluation Project, scientists on this team are “primarily concerned with determining the very least amounts of a prospective insec¬ ticide that can be used — with good results — in the forest.” ft P8*" t-JM j • Hr mi- ■w 1 “This approach represents a major shift in attitude and techniques for controlling insects,” Haverty says. “In the past, the only concern was, “Did you kill the pest?” In many cases, there was little or no concern for the fate of other organisms. Now, however, the approach is to deter¬ mine what can be done to manage destructive insects without damaging beneficial predators or parasites, or other forest organisms.” Project scientists, who are stationed in Berkeley, California, are currently working in three different areas of research. They are evaluating candi¬ date insecticides, to determine how effective these materials are in con¬ trolling defoliators — foliage-eating insects such as the western spruce budworm, Douglas-fir tussock moth, and larch casebearer. The team is experimenting with ways to control regeneration insects — pests that at¬ tack seeds, cones, young seedlings, and plantations. Finally, the re¬ searchers are developing techniques to prevent bark beetles from suc¬ cessfully attacking individual, high- value conifers, such as those in campgrounds and other recreation areas, seed orchards, research plots, greenbelts, or similar sites. Target: defoliators Over the past several years, the Insecticide Evaluation team has screened hundreds of insecticides, rating them for their potential effec¬ tiveness in killing major defoliators. These laboratory bioassays typically determined what doses were lethal to a specific percentage of the target pest population. A sister research team, the Field Evaluation of Chemi¬ cal Insecticides Research Unit in Davis, California, used the data in deciding which of the chemicals and dosage rates to select for further testing in the field. Research Chemist Mel Look says that analyz¬ ing tree bark and needles for insecticide residue is “like looking for a needle in a haystack — we have lots of substrate, con¬ taining only minute amounts of insecticide.’’ (Photo by Dennis Galloway) The spinning porous sleeve nozzle (far right) on the aerial application simulator produces the same size droplets as nozzles used in many aerial spray operations This and other features mean that the simulator can be used to replicate — on a small scale — many of the conditions that exist in an actual spray operation. The field tests are both time- consuming and expensive: a test of two chemicals applied at three dif¬ ferent dosages in an aerial spray operation, for example, can cost between $50,000 and $1 00,000. The goal of the field tests is to kill 90 per¬ cent or more of the insect popula¬ tion. Project Leader Haverty says that in the past, making the jump from dosages tested in the laboratory to the 90-percent-or-better control level in the field had been “almost pure guesswork,” with the result that sometimes dosages based on labora¬ tory findings weren’t effective in the field tests. For this reason, the In¬ secticide Evaluation Project has made major changes in its bioassay procedures. First, the team is now determining the quantities of a “can¬ didate” insecticide that are needed to kill 90 percent of the pest popula¬ tion. Second, the Berkeley group is changing the way that insecticides are applied in the laboratory. Before, insects were treated with either a drop of insecticide (applied directly on the insect’s body) or with a spray mist. After treatment, the insects were allowed to feed on an artificial diet. Now, the insects are sprayed as they feed on their natural diet of tree foliage. Because they have at least 24 hours before spraying to accli¬ mate themselves to the foliage, the insects have adequate time to build a feeding shelter — just as they would under natural conditions. The third change in procedure concerns the nozzle used in applying the insecti¬ cide. The new nozzle is a miniatur¬ ized version of the kind that is com¬ monly used in helicopter spraying. “In making these changes, we are trying to get a better simulation of field conditions,” Haverty explains. “There are still some factors we aren’t able to account for, such as the movement of spray away from the target (drift), breakdown of the insecticide in the sunlight (photo¬ degradation), and the coalescence and evaporation that occur when small droplets fall to the ground from a helicopter that is moving at 60 miles per hour. But, we hope that the changes that we are experimenting with will bridge the gap between laboratory tests and large-scale field tests.” Aerial simulator In a similar move to close this gap, Research Biologist Chuck Richmond and Instrument Maker Emanuel Moellman have designed an “aerial application simulator” — a device that can be moved about in the field and used to individually spray small trees. T rees that are from 3-to-1 2-feet high, and already have a natural infesta¬ tion of a target pest, are used in these experiments. The simulator consists of an 8-by-8-foot lightweight metal frame that adjusts to heights of from 6 to 1 2 feet. The frame sup¬ ports a motor-driven, battery-powered insecticide applicator that is equipped with a porous sleeve noz¬ zle. The nozzle produces droplets that are about the same size as those formed in helicopter tests. Nylon tarps extend from the metal frame to prevent the insecticide from drifting to surrounding trees. “We constructed the simulator so that it gives us the same pattern of large and small droplets that are characteristic of an aerial spray operation,” Richmond says. Small white cards made of glossy paper are placed around the base of test trees, to catch the spray droplets. A pink or red dye in the spray makes it possible to later analyze these cards and determine two key character¬ istics of the spray pattern — the number of drops per square centi¬ meter and the average diameter of the droplets. Adjustments are made in the aerial simulator until the pat¬ tern on the cards comes as close as possible to the actual spray patterns made on cards from previous heli¬ copter tests. Quantities used successfully in tests with the simulator convert easily into the standard gallons-per-acre measure needed for the aerial tests. Rearing colonies In the aerial simulator experiments, researchers can use natural popula¬ tions of target pests. The laboratory bioassays, however, require either importing or raising large quantities of insects. Research Entomologist Jackie Robertson has developed new and successful techniques for rear¬ ing laboratory colonies of two target pests — the western spruce budworm and the Douglas-fir tussock moth. 2 Her research involved making count¬ less modifications in the artificial diet required for these insects, and numerous experiments to determine the proper breeding, feeding, and rearing conditions. Using Robertson’s guidelines, the Unit can now produce a continuous supply of the thousands of healthy, early maturing western spruce budworm and Douglas-fir tussock moth that are needed each week for bioassays. Robertson is also involved in two other areas of research. One is the development of computer programs that can quickly analyze laboratory data about response of the budworm, tussock moth, and other insects to various doses of insecticides. The POLO-1 and POLO-2 (Probit or Logit Analysis) programs that she and col¬ leagues from the Experiment Station and from Cambridge University have developed are statistically sound, easy to use, and more informative than any other computer programs currently available for these types of analyses. In a second area of research, Robertson and colleague Molly Stock of the Department of Forest Re¬ sources at the University of Idaho, Moscow, have studied western spruce budworm to determine if genetic differences among budworm populations may correspond with natural immunity, or resistance, to certain chemicals. “If a population has a natural, genetically controlled immunity to an insecticide, applying the material would make the situation much worse,” Robertson explains. “The budworms that survive the spraying will be those that are the most resistant; by spraying, the population would be pushed toward even greater resistance.” Stock and Robertson have tentatively identified at least one budworm population that seems to have a strong resistance to a commonly used insecticide. They hope to determine if there is a genetic marker, such as one of the esterase enzymes, that would be a reliable indicator of resistance. Parasitized budworms In other studies of defoliators, Research Biologist Marion Page is determining how parasitism affects the response of western spruce bud¬ worms to insecticides. The parasitic wasps Glypta fumiferanae and Apanteles fumiferanae are being used in these experiments. A previous study by Research Ento¬ mologist Carroll Williams of the Sta¬ tion’s Integrated Pest Management Unit, and colleagues, suggested that the ratio of parasitized to non- parasitized budworms was higher after the insects had been sprayed. “Parasitized budworms may be less mobile and may have less chance of coming in contact with the spray,” Page explains. His purpose in learn¬ ing more about this phenomenon is to determine if — through elimination of nonparasitized budworms — spray¬ ing gives parasites a better chance to reduce the remaining budworm population. “We may find that spray¬ ing will knock the budworm popula¬ tion down to a point where the para¬ sites can take over. If this turns out to be the case, it would mean that we were one step closer to achieving control of the pest population through natural means. This is the goal of in¬ tegrated pest management.” The parasitic wasp Glypta fumiferanae in¬ jects its eggs into a young western spruce budworm. Page and colleague Nancy Rappa- port, also of the Insecticide Evalua¬ tion Project, are the first to raise an on-going laboratory population of Glypta. For their studies, Glypta females will be allowed to parasitize some budworms from the laboratory colony. Then, Page will monitor the response of the parasitized bud¬ worms to application of several in¬ secticides, including mexacarbate and carbaryl. Similar experiments with Apanteles will follow. 3 Regeneration insects Among the regeneration insects that the researchers are studying is the mountain pine cone beetle, a pest that has repeatedly destroyed much of the cone crop produced in the Forest Service’s western white pine seed orchard in Sandpoint, Idaho. The Berkeley Unit is helping the Field Evaluation Unit develop a pest man¬ agement strategy that can be used to protect future cone crops from the pine beetle. The study will provide guidelines for estimating the size of each year’s beetle population, and for predicting the exact date when beetles will emerge from overwinter¬ ing. According to Research Ento¬ mologist Pat Shea, who is leader of the Davis team, this information is needed to properly schedule the spray operation. “Timing is critical,’’ Shea says. “The cone beetle can attack the conductive tissue in a pine cone — and effectively kill the cone — in less than a hour. And, the beetle usually begins its attack less than 24 hours after it emerges from overwintering." The Sandpoint work so far has in¬ dicated that the trees must be sprayed with insecticide just before the beetles emerge for flight in early spring. Shea and Plaverty hope to be able to pinpoint the emergence date in “degree days” — a cumulative measure of temperatures that occur as winter turns to spring and the in¬ sects prepare to emerge. The insec¬ ticide used in the seed orchard test this past spring was permethrin, a material that Plaverty describes as “safe and fast-acting.” Carefully measured doses of an insecticide were added to the mold of artificial diet. The smaller budworms are those that have shrivelled and died. (Photo by Dennis Galloway) In another study of regeneration in¬ sects, Research Entomologist Rene, Pieper and University of California at Berkeley Researcher W. Jan Volney of the Division of Entomology and Parasitology are analyzing the insect pests of a Douglas-fir seed orchard in the foothills of the west-side Sierra Nevada in central California. Pieper and Volney have monitored the number, position, and condition of flowers (and later, cones) of Douglas- fir from different sources and clones, and have dissected and analyzed some of these cones in the labora¬ tory. The purpose of their study is to develop methods to predict, detect, and monitor insect damage to cones and seed crops. Protecting ponderosa The Project’s newest area of research concerns techniques for individually treating high-value ponderosa pine with insecticides, to protect them from bark beetles. In cooperation with the Davis team, Project Leader Plaverty is monitoring the effectiveness of applying the in¬ secticide carbaryl in the fall months. Pie will compare these findings with the results of a previous study, in which carbaryl was applied in the spring. The advantage of the fall ap¬ plications would be that fewer forest visitors would be staying at camp¬ sites or cabins, or visiting Ranger Stations, at that time. 4 In another experiment, Haverty and the Davis team are determining whether any environmental contami¬ nation or risk to the person applying insecticide results when either a pump tank with a hose or a large hydraulic sprayer is used. “Drift, splash, and “misses” are the types of contamination that concern us,” Haverty says. Residue analysis The contamination study will include a procedure known as residue analy¬ sis. Samples of tree foliage and bark, along with other vegetation, and soil, are used in these analyses to deter¬ mine how much insecticide actually reaches the intended target, how long the insecticide persists in the environment, and how far it drifts. Residue analysis is a specialty of Research Chemist Mel Look, who says that most of the more widely used techniques are designed for analyzing insecticide residues on agricultural crops. “These techniques don’t really meet our needs in forestry,” Look says. “For one thing, the substrates are different — we need to analyze residues on grasses, the litter layer, or conifer foliage, not on a cotton plant. Also, we are work¬ ing with submicrogram quantities of insecticides: most conventional residue analysis techniques are designed for working with much larger amounts of chemicals.” Look is currently experimenting with different approaches that might shorten the lengthy and time- consuming procedure that is known as “clean up” — extracting or separating the insecticide residue from the waxes, resins, and other substances that are contained in foliage and bark samples. One method he is trying is exclusion li¬ quid chromatography, in which the field sample of bark, foliage, or other material, is ground up into find par¬ ticles, extracted with solvents, and passed through a glass column. The spaces between the molecules of organic material in the column serve as a filter, and segregate the incom¬ ing molecules according to their size. This size-sorting separates the insec¬ ticide from the other materials. A gas or liquid chromatograph is then used to determine how much insecticide was in the sampled area. Another technique that Look is test¬ ing is called differential absorption. With it, the ground-up field samples and solvent are separated according to their positive or negative charge. The residue analysis guidelines that Look develops will be used by the other researchers in the Project as part of their aerial simulation tests, bark beetle tests, or other studies. This interrelatedness is typical of the research team: each scientist is working in a highly specialized area of study, but all of the areas are closely related. And, although the methods and materials used in the Project’s more than 20 different studies may differ, the goal of each of the studies is the same — to pro¬ vide safer, more effective ways to manage destructive forest insects. A bibliography of reports and technical articles that Insecticide Evaluation Project scientists have published recently is available to Forestry Research West readers. To request a copy, write: Dr. Michael I. Haverty, Insecticide Evaluation Proj¬ ect, PSW Station, P.O. Box 245, Berkeley, California 94701 . - H - “This publication reports research involving pesticides. It does not con¬ tain recommendations for their use, nor does it imply that the uses dis¬ cussed here have been registered. All uses of pesticides must be registered by appropriate state and/or Federal agencies before they can be recommended.” Old-growth forests by Samuel T. Frear Pacific Northwest Station Each old growth Douglas fir Is shaped over centuries of time by a host of factors to make them highly individualistic. f W' - v / ;58k The first glimpse of old-growth Douglas-fir forests blanketing the mountain slopes of the Pacific North¬ west can be awe-inspiring. The immensity of the trees, the number of them, and the intensity of their shade are among the elements that reinforce the first impression: these are very special trees. And the old-growth coniferous forests of Northern California, Oregon, Washington, and British Co¬ lumbia are very special. They are virtually unique on the globe: Only in limited places elsewhere on earth are the conditions present to permit such forests. These forests, of which the Douglas- fir is the most prominent member, can have trees that tower up to 300 feet with a diameter of 1 0 feet or more. Trees continue growing for many centuries, sometimes to an age of 1 ,000 years, with a biomass per acre higher than most other species. The massiveness of the tree, along with its extreme longevity, is distinctive. These trees affect the atmosphere, and a first-time visitor notices the coolness of the air beneath their canopy in summer, and its warmth during winter. 6 Knowing these things, standing in the midst of an old-growth stand, repeat¬ edly brings out wonder. A young forester from the East stood beneath a towering Douglas-fir for the first time and said in amazement, “Look at all that energy.” Yet, as we more and more appre¬ ciate these old-growth trees, we become increasingly aware of how little we know about them. What roles do the live trees and the dead trees play in the ecosystem? How do they affect streams and rivers? In what ways do wildlife need them? How do they fit into the web of life that interconnects all living things? What characteristics do the trees have that must be perpetuated? These questions are relevant as we begin to realize that the world’s resources are finite. It is important to raise these questions while there still are thousands of acres of old-growth stands remaining in the Pacific Northwest. To set a framework for discussion of old-growth forests, a group of scien¬ tists at the Pacific Northwest Forest and Range Experiment Station’s For¬ estry Sciences Laboratory and Oregon State University in Corvallis, Oregon, have compiled a summary of research about all aspects of the old-growth forests as a background for discussion of future research needs and proposed forest manage¬ ment practices. They suggest poli¬ cies that forest managers can imple¬ ment to protect old-growth values within various land allocations or timber management plans. Jerry Franklin, a research forester and project leader in Corvallis, says there were several reasons for compiling information about the old- growth forests of the Pacific North¬ west. First, he believes the informa¬ tion will be useful to land managers. Secondly, it was interesting to put together all the studies of old-growth “just to see what we did know.” Thirdly, the public has become inter¬ ested in old-growth timber. Outstanding characteristics To set the stage for discussion of the structure and function of old-growth forests and the management strate¬ gies necessary to protect them, it is first important to understand just how unique they are. The biomass of old-growth forests is astounding. The Pacific Northwest forests contain one of the largest biomass accumulations in the world. Theories about forest growth have been shattered as more is learned about them. There just is no com¬ parison to other forests in temperate areas. The above ground biomass for Douglas fir/western hemlock aged 250 to 1 ,000 years averages 345.7 tons per acre, compared to 96.8 tons per acre for mature temperate decid¬ uous forests and 1 26.7 tons per acre for mature tropical rain forests. In terms of productivity, the ad¬ vantage the Pacific Northwest old- growth trees have is their sustained height growth and longevity. They continue to grow substantially in diameter and height for decades after trees in other temperate regions have reached equilibrium. Still another outstanding feature of Pacific Northwest forests is the dominance of evergreen coniferous trees. A unique phenomenon is that there are ratios of 1 ,000 evergreens to one hardwood in old-growth for¬ ests, different from most temperate regions of the world where decidu¬ ous hardwoods or a mixture of hard¬ woods and conifers are dominant. There has been much speculation about the reasons for the evergreen dominance in the Pacific Northwest, but climate appears to be the critical factor, Franklin believes. Evergreen coniferous trees are well adapted to the unusual climate of the Pacific Northwest — wet, mild winters and warm, relatively dry summers. Deciduous hardwood species, on the other hand, have considerable disad¬ vantages competing with conifers in this climate. The conifers, in contrast to hardwood, can utilize the dormant season for photosynthesis; they are not dependent on assimilation during the growing seasons, a time when photosynthesis is frequently con¬ strained by the dry summers. Thirdly, conifers have lower nutrient require¬ ments and need not get this from the soil at a time when decomposition and nutrient release are at a minimal level due to reduced soil moisture. Dominance by evergreen conifers appears to be an evolutionary response to peculiarities of the Pacific Northwest climate. Still another unique aspect of the old-growth forest is the massive size of trees. Although more research is needed to determine what advantage this has, it seems obvious that large size and longevity have adaptive ad¬ vantages. They allow a species to overtop species of smaller structure, or to outlive species of short life span, or both. Long lived species can span long periods — sometime centuries — between natural destruc¬ tive episodes. And the large size allows buffering against all the slings and arrows the environment throws up to affect adversely all but the strongest, the biggest, and the best. In view of all these unique qualities, Franklin is amazed that there is lack of quantitative data on various aspects of forest succession in the Pacific Northwest. Although these forests have been observed for a hundred years or more, most analy¬ ses are either anecdotal, or based on inference drawn from tables and charts. But the times are changing. Large logs may take several centuries to decay, serving as a complex, meticulous source of energy and nutrients. Structural components of old-growth forest Franklin looks at the old-growth forests in terms of its four structural components: large, live trees; large snags; large logs on land; and large logs in streams. What characteristics in each of these components should be perpetuated or re-created, and why? Living trees Old-growth trees are highly in¬ dividualistic; ages of trees vary con¬ siderably, and a stand is much less uniform than are 50- to 1 50-year-old stands. Each old-growth tree has been shaped over the centuries by its genetic heritage, site conditions, competition with nearby trees, and the effects of storms, diseases, in¬ sects, and soil movement. These old trees have important ecological roles: It is these structural components that are, in large measure, unique to an old-growth forest ecosystem, setting it apart from young growth and man¬ aged stands. Most of the unique or distinctive features of old-growth forests can be related in terms of flora and fauna (thus, how it is com¬ posed) and the way in which energy and nutrients are cycled (the forest's functions). The tree plays a progres¬ sion of roles for the time it is alive through its transformation to an unrecognizable component of the forest floor. 1 . They are the habitat for distinctive epiphytic plants (plants that live on other plants, such as moss and lichens). More than 100 species of moss and lichen function this way. When moist, the canopy is an impor¬ tant climatic buffer, capable of holding 264,000 gallons per acre. This is important for the survival of lichen Lobaria oregana, an important fixer of nitrogen in the environment. 2. They have important effects on carbon, nutrient, and water cycling. A single old-growth tree can have more than 60 million needles weighing 440 pounds with a surface area of 30,000 square feet. The tree is a large photosynthetic factory. 3. It is the source for other key struc¬ tural components of the ecosystem: standing dead trees, logs on land, and logs in streams. These trees also serve as the habitat for invertebrates. A single stand may have more than 1 ,500 species. Researchers found that only a minor¬ ity of these spend their entire life in the canopy. The majority are adults which have spent their immature stages on the forest floor or in streams. Standing dead trees (snags) Large standing snags in excess of 20 inches dbh and 65 feet in height are most valuable in an old-growth stand, particularly as a habitat for a variety of vertebrate and invertebrate animals, birds and insects. Snags usually last for 50 to 75 years in natural stands before they deterio¬ rate to stubs less than 35 feet which are of little value as habitat for fauna. Franklin reports that this aspect of old-growth forests needs more study. New research is under¬ way, however, that is expected to generate useful information. Large logs on land There typically are 38-85 tons of logs per acre in old-growth forests. They are an important source of nutrients such as nitrogen and potassium. Large logs disappear much more slowly than standing snags. It is estimated that it requires 480 to 580 years for a 30-inch dbh Douglas-fir to become 90 percent decayed. During this time these logs are a haven for many hundreds of insects. Reporting on these in a March 1 981 issue of Natural History, author Mark Deyrup reported: “There is a new vision of the deadwood in forest and woodlot, deadwood that is no longer the very symbol of unproductivity, but rather a complex, meticulous recy¬ cling station that deposits minerals and humus on the ground, while pouring forth the stored energy of the tree in a swarm of organisms indis¬ pensable to forest food chains.” Franklin agrees: “The most impor¬ tant function of logs are as sinks and storage compartments for energy and nutrients and as sites for nitrogen fixation.” Documenting the importance of these logs, he said, is some of the most significant research conducted about old-growth groves in recent years. “We just didn’t know as much as we should have about the woody debris on the forest floor,” he stated. Logs in streams Logs are at least as important, and possibly more so, to the stream com¬ ponent of the old-growth ecosystem as they are to the terrestrial com¬ ponent. The logs are a dominant ele¬ ment in streams for distributing aquatic habitats, providing stability of streambeds and streambanks, and in routing sediments and water. Large debris remains in water for a long time, commonly from 25 to more than 100 years. In smaller streams, logs cause the energy of streams to be dissipated at falls and cascades, causing less erosion. There is more sediment stor¬ age in channels, slower routing of organic detritus, and greater diversity of habitat. Large debris may be the principle factor determining the char¬ acteristics of aquatic habitats for fish and for microbial, invertebrate, and vertebrate organisms. The woody debris itself is a major source of energy and nutrients for the stream system. These, then, are the structure and function of the four components of an old-growth forest. Researchers are convinced that they are of over¬ whelming importance, performing roles without which a forest eco¬ system would not survive. How, then, can land managers protect, enhance, and perpetuate the functions of an old-growth forest? The key is tying management decisions to the four components, Franklin believes. Large standing snags last from 50 to 75 years, and are habitats for a variety of wildlife. Management alternatives Franklin says there are three alternatives: (1) Perpetuate existing old-growth stands. This is the surest course of action since old-growth conditions can persist for several centuries. (2) Re-create ecosystems with old- growth characteristics using long rotation periods between harvesting. (3) Provide for individual old-growth features in any timber management plan. This involves applying practices to the main body of commercial for¬ est land. Some of the most important ecological features of old growth can be duplicated with relatively small impact to timber production. If forest managers decide to imple¬ ment either of these alternatives, they will have to decide how the old-growth allocation should be distributed, which management prac¬ tices should be followed in areas selected for retention and for long rotations, and the size and shape of old-growth areas. The ecologically most desirable man¬ agement unit is an entire drainage basin, preferably of from 300 to 500 acres, Franklin believes. These have natural topographic boundaries pro¬ viding protection to the stand, and natural land-water interaction allow¬ ing inputs of wood debris to con¬ tinue. Plant and animal diversity will be higher. Protecting old growth along streams is also a workable alternative. The trees not only shade and minimize water temperature increases, but also provide energy to the stream, and debris to create dams. These streamside areas also can provide migration routes for organisms that need mature forests. Streamside old- growth stands, too, can provide con¬ tinuity to the forest, and will avoid the loss of species in “islands” of habitat. Success in managing forests for old- growth characteristics will depend on learning to manage the dead, or¬ ganic material as imaginatively as live trees. Decaying snags and logs, particularly in streams, are more beneficial than previously thought. Franklin hopes they no longer will be viewed solely as waste, a fire hazard, or impediments to management. When managing for old-growth char¬ acteristics, the forester can provide for retention of large snags and logs. These are much more than habitats for vertebrate animals. Their value for cycling and conserving nutrients, especially nitrogen, is important — a fact that 1 0 years ago was not known. It appears, Franklin says, that at least several large logs per acre should be left following timber har¬ vesting. But more research is needed. Logs in streams are a dominant element for distributing aquatic habitats, providing stabil¬ ity, and in routing sediments and water. The retention of small groups or in¬ dividual old-growth trees may also be useful as a technique for providing a source of epiphytes to adjacent young trees. Also, in the long run, this old growth will provide the forest with a source of snags and logs. Franklin is convinced that research on old-growth trees is just getting started. Now that numerous studies are underway or planned for the future, he anticipates that our under¬ standing of the ecological function of these trees will increase immeasur¬ ably. This, in turn, will provide addi¬ tional insight for forest managers to plan for this forest resource in con¬ junction with other resources. Then, too, the term “decadent” tree will disappear from our vocabulary as we better understand that at every stage of its existence a tree performs vital environmental functions. For further reading The following publications are available from the Pacific Northwest Station: Franklin, Jerry F.; Cromack, Kermit; Denison, William; and others. Ecolog¬ ical Characteristics Of Old-Growth Douglas-Fir Forests. USDA Forest Service General Technical Report PNW-1 18. Portland, Ore., Pacific Northwest Forest and Range Experi¬ ment Station. 1981 . Franklin, Jerry F. and Waring, Richard H. Distinctive Features Of the Northwestern Forest: Develop¬ ment, Structure, and Function. In Proceedings of 40th Annual Biology Colloquim: 59-86, Corvallis, Ore; Oregon State Univ.; 1979. 10 Learning to manage southwestern riparian ecosystems by Matthew McKinney Rocky Mountain Station Southwestern riparian vegetation changes with elevation. Here, a cottonwood-willow association meanders through the arid countryside along the floodplain. Rare, oasis-like riparian zones, fed by surface and subsurface water, provide a welcome contrast in semi- arid New Mexico and Arizona. Often supporting more diverse plant and animal communities than surrounding ecosystems, riparian zones play a unique and valuable role in South¬ western ecology — extending from the arid desert floor to cool mountain meadows. According to Robert Szaro, riparian specialist with the Rocky Mountain Station’s Forestry Sciences Labora¬ tory in Tempe, Arizona, “Conflicts between wildlife and human popula¬ tions make preserving and managing riparian zones of increasing concern to land managers, property owners, and others.” Forest Service scientists, cooperating with several state and federal agencies, are working to find better ways of managing riparian ecosystems while minimizing conflicts. Because the Southwest is one of the fastest growing regions in the U.S., natural resources are in high de¬ mand. And people are attracted to riparian zones which offer not only livestock grazing, timber products, agriculture opportunities, recreation, and homebuilding sites, but also shade, water, lush vegetation, and diverse wildlife species. Wildlife, like people, are also drawn to these wet and wooded areas for feeding, resting, and drinking. Wildlife use riparian zones because of their increased floral diversity and density relative to upland vegetation; a large amount of edge (i.e., the interface between two different plant and animal associations); loose, deep soil in which to burrow, tree cavities for nesting and perching; and often times abundant food and water. Many species use riparian areas throughout the year as breeding sites, wintering areas, and as migra¬ tory corridors. Southwestern riparian zones are also home to several threatened and endangered wildlife species. The bald eagle is one, depending on the riparian ecosystem for its primary food source, fish. The Gila trout and Arizona trout, both native to the Southwest, are threatened because of competition with more popular, introduced sport fishes. Although Southwestern riparian zones are typically long and narrow, winding through the arid countryside, various land use practices have created “riparian islands” — i.e. areas isolated from larger riparian zones and concentrated around localized water sources such as springs and wells. Consequently, wildlife and their habitats are adversely affected by these human activities through stream and river diversions, soil compaction and run¬ off, trampling and clearing vegeta¬ tion, collecting firewood, ground water pumping, and so on. Several birds, like this Harris Hawk, and other wildlife depend on riparian ecosystems for feeding, breeding, nesting, and resting sites. Szaro believes, “Land managers need better guidelines to stop the rate of vegetation loss and insure the replacement of this vital ecosystem. Our primary objective should be to maintain a healthy ecological system where species can reproduce natu¬ rally. However, the variety of plant- animal associations in Southwestern riparian zones make it difficult to develop generalized management practices.” But Szaro, along with many other scientists, are identifying and record¬ ing tree and perennial plant species for all elevation gradients of the riparian zone in Arizona and New Mexico. Once this is done, a classifi¬ cation system will be developed to aid land managers in determining the tradeoffs involved when riparian areas are designated for various uses — wildlife habitat, livestock grazing, agriculture, timber products, recrea¬ tion, homebuilding, and so on. At the same time, scientists will identify which wildlife species depend on which plant communities for food and cover, thereby letting land managers know which species will be affected - and taken into account - by his/her decisions. Computer programs, in¬ cluding RUN WILD and ECOSIM, are helping scientists identify food and cover requirements for many species, and in developing management guide¬ lines for Southwestern riparian ecosystems. Management implications so far Research at the Tempe Lab indicates that one of the major conflicts in Southwestern riparian zones is wildlife - livestock interactions. Cattle, the most common livestock in the Southwest, prefer riparian zones for a variety of reasons. For in¬ stance, the quantity and quality of forage is higher and more palatable in riparian zones than adjacent upland forage. And cattle prefer to browse young tree seedlings such as cottonwood, ash, and willow, which are common in riparian ecosystems. Cool and shady, riparian zones also offer cattle protection from the scorching sun and dry desert wind. But, wildlife managers frequently claim that overgrazing by livestock tends to disrupt and even destroy riparian vegetation, thereby reducing wildlife habitat. Studies show that although short-term fencing-off of riparian areas doesn’t change plant species composition much between grazed and ungrazed areas, seedling reproduction and herbaceous under¬ story increase on ungrazed areas. Szaro says the lack of seedling reproduction is one of the major factors causing the decline of South¬ western riparian zones. 12 To get a better understanding of wildlife-livestock interactions in riparian zones, scientists are using a time lapse movie technique to study methods of manipulating livestock grazing to increase forage quantity and quality for wildlife, and to decrease grazing effects on seedling reproduction. By associating wildlife species and livestock to different vegetation types, scientists will provide land managers with manage¬ ment guidelines. Diversity and indi¬ cator species may also be useful to land managers as an index to habitat quality and allow them to manage groups of species with common requirements. Another research application im¬ portant to land managers is a new method for censusing bird popula¬ tions called the “variable circular-plot method.” Szaro says, “Accurately estimating bird populations has been a major concern to biologists for years. Common censusing methods, such as spot-mapping and transects, present problems when applied to small, island-like areas with hetereogeneous vegetation. Spot¬ mapping is limited to breeding seasons when birds defend terri¬ tories, while riparian islands are too small and variable for transects. This new censusing method is not limited to breeding seasons, and is appli¬ cable to small habitat islands.” Research needs for management In addition to the comprehensive plant - animal classification system, land managers need information on the life histories of plant and animal species, and the influence of human activity on riparian zones, to develop management guidelines. According to Szaro, life history in¬ formation provides biological data useful in understanding each species role in the ecosystem. In the past, researchers have neglected the life histories and habitat needs of non¬ game birds, reptiles, amphibians, and mammals such as bats, squirrels, and skunks in favor of more eco¬ nomically important species. How¬ ever, scientists now recognize the importance of all wildlife, including threatened and endangered species, in the food chain and in managing entire ecosystems. In addition, life histories on important riparian tree species — sycamore, cottonwood, willow, ash, and walnut — are almost non-existent. Studies on germination and sprouting of seed¬ lings, effects of fire and insects, and techniques for artificial regeneration are needed. Human influences on Southwestern riparian ecosystems are probably in need of the most research. Grazing, pollution, recreation, flooding, and water reclamation projects all impact riparian zones. Land managers need to know recovery rates of ecosystems with different amounts and types of pollutants, and their chemical toxicity to plant - animal associations. Managers also need information on the carrying capacity of riparian ecosystems to regulate recreational, homebuilding, and other human uses. Data on minimum water flows and tables will enable land managers and property owners to maintain riparian habitat as a vital biological resource while mitigating losses from dam and reservoir projects. An understanding of the various uses and their impacts on riparian ecosys¬ tems should provide land managers a means for evaluating alternative management decisions. Szaro says, “Management objectives should seek a balance between multiple use and perpetuation of the riparian ecosystem.” Flooding may either damage a riparian zone or create new seed beds. Here, winter flooding exposes roots of a cottonwood. 13 Research on the desert by Tom Baugh Intermountain Station Sheep are grazed and studied on the Desert Experiment Range. The Great Basin is a vast interior region of the United States bordered on the west by the majestic Sierra Nevada and the southern Cascade Mountain ranges and on the east by the precipitous Wasatch Range and the west face of the Colorado Plateau. This immense area includes all of Nevada, the western third of Utah, parts of eastern California, southeastern Oregon and southern Idaho. The Great Basin is generally charac¬ terized as arid. This is, however, a land of amazing contrasts including areas such as Utah’s Great Salt Desert, productive wetlands such as the Ruby Marshes, and rolling shrublands. Throughout the region numerous mountain ranges rise like islands from surrounding seas. Most Great Basin rangeland is grazed by livestock — this industry is vital to the rural economies of this area. For example, federal ranges provide 30 percent of the livestock feed re¬ quirement in Utah and 45 percent in Nevada. Rangelands and the associ¬ ated waters provide habitat for thou¬ sands of big-game animals and count¬ less other wildlife including songbirds, upland game birds, waterfowl, and fish. These wildlife resources provide hunting and fishing opportunities and many other nonconsumptive val¬ ues. Demands on the rangeland re¬ sources for recreation also increase with each passing year. It is important that these rangelands be managed to maintain or improve all range resources. During the latter 1 970’s, however, it was estimated that much of the Great Basin range- land was only producing half of its potential livestock forage, wildlife habitat, and protective watershed cover. Scattered throughout the Great Basin are thousands of hectares of salt desert. These areas are character¬ ized by minimal precipitation. Vegeta¬ tion is limited to those hardy species which can survive low moisture and highly varying temperatures. Temper¬ atures can range as much as 28° C during one day. Desert experimental range The Desert Experimental Range is located about 75 km (47 miles) west 14 of Milford, Utah. This 22,000 hectare area represents much of the lower elevation land throughout the Great Basin. About 75 percent of the Ex¬ perimental Range is alluvial slope or flat valley bottom. The rest is steeper rockland overlain by a shallow soil mantle and broken by ledges of hard Paleozoic sedimentary or Tertiary volcanic rock. Elevations range from 1 ,547 to 2,565 meters. Soil textures are typically loams, sandy loams, or loamy sands. The ground is frozen most of the time from mid-November into March. Snowfalls are usually light, seldom more than 5 cm deep. Snowfall of 25 cm or more may only occur 1 year out of 1 5 in early winter, but as often as 1 year out of 3 in late winter. The average annual precipita¬ tion is 1 57 mm, about half of which falls during the 5-month period from May through September. The vegetation on the Experimental Range is a mosaic of low shrub and shrub-grass types. The different vegetational types reflect soil differ¬ ences between sites. The dominant shrub species are winterfat, bud sagebrush, black sagebrush, shad- scale saltbush, and little rabbitbrush. Three perennial grass species, Indian ricegrass, galleta, and sand dropseed are associated with shrubs on most soils. Only one native ruminant, the prong¬ horn antelope inhabits the Desert Ex¬ perimental Range. Jackrabbits and cottontail rabbits are found in or near the dry washes, on rocky slopes, and in canyons where taller shrubs pro¬ vide concealment. Nine species of rodents are found throughout the area. Six species are mice and kan¬ garoo rats, and three species are ground squirrels and pocket gophers. Predators include the coyote, kit fox, badger, weasel, two species of skunks, and an occasional mountain lion. Raptors are also common. Research Grazing studies began on the Desert Experimental Range during the winter of 1 934-1 935. Twenty large (129 ha) range pastures were each assigned a season or combination of seasons to be grazed by sheep at different stocking intensities. The rest of the area was divided into 1 4 units. Over the years, 1 1 have been grazed by sheep and two by cattle. One unit has not been grazed. It was from the studies on these plots that research has shown that proper resource management techniques have the ability to increase forage production by 45 percent. Researchers have demonstrated the importance of season and intensity of grazing on salt desert shrub vegetation. Heavy grazing in late winter and early spring causes severe reduction of desirable peren¬ nial species which allows an invasion of undesirable plants in some years. This does not occur where proper management has maintained vigor¬ ous stands of desirable perennial species. Long-term studies on the Desert Ex¬ perimental Range have shown that the principal perennial species are long-lived and generally suffer little mortality after the second year of establishment. Winterfat, a small shrub species which is an important source of livestock forage, appears to have maintained a consistent pres¬ ence in part because of this longev¬ ity. In 1 975, over one-half of the plants present were at least 40 years old, and the individuals surviving that period continued to increase their size. Shadscale, on the other hand, has had a higher mortality rate and has had to depend on a higher rees¬ tablishment rate to maintain its status in the community. Its abun¬ dance has declined. Budsage has shown the most sensitivity to grazing of the three principal shrubs, but tends to replace shadscale when protected from grazing. Overall, how¬ ever, there has been surprisingly few significant differences between the survival of plants in the ungrazed plots versus plots grazed during dor¬ mant periods. In these communities of widely spaced perennials, much of the plant tissue is unseen. Only 14 percent of the mass of accumulated organic matter is above ground. The great majority occurs as roots in the unseen underground environment, although much of the underground nonliving organic materials appar¬ ently originated above ground and were worked under the soil surface by animal activity. One of the more interesting finds which has been developed in part on the Desert Experimental Range relates to the role played by nonvas- cular plant communities in the pro¬ tection of arid soils. These communi¬ ties, which appear like a carpet over the soil, are known as cryptogamic crusts. Although the major compo¬ nent of the crust is algae, lichens and mosses may also be present. When the crust is intact it acts to preserve the soil from wind erosion. When the crust is disturbed, for ex¬ ample, by heavy grazing — especially during the summer — the underlying soil may become subject to erosion. It has been estimated that once a site is seriously disturbed and robbed of its cryptogamic crust, it could take 1 5 years before the crust becomes reestablished. Many of the research programs on the Desert Experimental Range are cooperative efforts. For example, researchers of the Intermountain Forest and Range Experiment Sta¬ tion’s Shrub Sciences Laboratory and the Utah Division of Wildlife Resources have recently completed studies that show antelope can flourish on valley bottoms, where they are not ordinarily found, if drink¬ ing water is made available for them. On many of these unoccupied areas the topography and forage are suit¬ able but, unfortunately, the water is usually not present. The development of additional watering places helps increase potential antelope range. Researchers hypothesize that making more water sites available during fawning season helps distribute the antelope population and may lessen the number of fawns killed by predators. 15 / \ Forage must also be available to sus¬ tain antelope. Studies have shown that the preferred winter forage on the Desert Experimental Range is black sagebrush. Antelope will also feed on grass for a short period in early spring while the growth is new. The production of forbs, which are preferred summer forage, is variable from year to year depending on the amount and time of summer rainfall. Research has demonstrated that suc¬ culence is the most important aspect of the feed antelope prefer. When forage is succulent, antelope do not drink water. In dry summers, how¬ ever, they drink almost 3 liters per day. The future Although there have been significant gains in knowledge and techniques, much remains to be done. The Intermountain Forest and Range Experiment Station is involved in a comprehensive range research and application program. Part of this pro¬ gram includes the Desert Experimen¬ tal Range. The mission of the pro¬ gram is to increase the capabilities of land managers to maintain and improve the quality and productivity of Great Basin rangelands. Antelope are the only native ruminant on the Desert Experimental Range. The program is composed of three parts: 1 . To accelerate information dissem¬ ination and application of present technology; 2. To establish field tests, based on available knowledge, to demonstrate and evaluate the overall effective¬ ness of management prescriptions; and 3. To accelerate the research needed to enhance and protect range resource uses and values. Because of the land management and ownership patterns in the Great Basin, it is important to note that the range research and application pro¬ gram is a cooperative effort of Federal, State, and local agencies and of the private sector. Access to research For additional information concerning the Desert Experimental Range con¬ tact one of the following; Intermountain Forest and Range Experiment Station 507 25th Street Ogden, UT 84401 Intermountain Forest and Range Experiment Station Shrub Sciences Laboratory 735 N. 500 E. Provo, UT 84601 For further reading, the following publications are available from the Intermountain Station: Holmgren, Ralph C., and Sam F. Brewster, Jr. 1972. Distribution of Organic Matter Reserve in a Desert Shrub Community. USDA For. Serv. Res. Pap. I NT-1 30, 15 p. Intermt. For. and Range Exp. Stn., Ogden, Utah. Holmgren, Ralph C., and Selar S. Hutchings. 1972. Salt Desert Shrub Response to Grazing Use. In Wild¬ land Shrubs - Their Biology and Utili¬ zation, Proc. Int. Symp. p. 153-164. USDA For. Serv. Gen. Tech. Rep. I NT-1 . Intermt. For. and Range Exp. Stn., Ogden, Utah. Hutchings, Selar S. and George Stewart. 1953. Increasing Forage Yields and Sheep Production on in¬ ter mountain Winter Ranges. U.S. Dep. Agric. Circ. 925, 63 p. Washing¬ ton, D.C. Stewart, George, W. P. Gottorn, and Selar S. Hutchings. 1940. Influence of Northern Salt Desert Plant Associ¬ ations in Western Utah. J. Agric. Res. 60:289-316. 16 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. Understanding dwarf mistletoe Dwarf mistletoes are parasitic plants that rob conifers of nutrients and water, causing a decline in tree vigor. They are a problem in the western United States, where they stunt and kill western larch, ponder- osa pine, lodgepole pine, Douglas-fir, western hemlock, mountain hemlock, and true firs. In 1 978, 41 percent of the stands east of the Cascades and 1 0 percent of those west of the Cas¬ cades in Oregon and Washington were infected. Over a 10-year period infected Douglas-fir in the Okanogan National Forest had 10 percent more mortality than trees not infected. Volume losses as high as 37 percent have been found in western hemlock. A new publication from the Pacific Northwest Station summarizes essential biological knowledge about dwarf mistletoes and answers ques¬ tions about managing infected stands. The paper discusses the ways the six main species of mistle¬ toe are spread through trees and stands and their effects on growth and mortality of trees. The amount growth is reduced depends on in¬ teracting factors that include the ex¬ tent of infection, location within tree crowns, length of time present, age of trees, and stand density. After a decline in growth and vigor, trees eventually die of root rots or bark beetles. Since mistletoes grow on nutrients and water stolen from trees, it is im¬ portant to select management prac¬ tices that favor growth of trees without indirectly increasing mistle¬ toe growth. Recommendations for doing this are provided in Dwarf Mistletoe and Host Tree Interactions in Managed Forests of the Pacific Northwest by Donald M. Knutson and Robert Tinnin, General Technical Report PNW-1 1 1 . Copies are avail¬ able from the Pacific Northwest Station. Evaluating slash fuel hazards Commercial timber harvesting often leaves large quantities of combusti¬ ble residues on the forest floor. This residue, also known as slash or ac¬ tivity fuel, increases fire hazard, hinders stand management, disrupts wildlife and livestock grazing, chokes stream channels, and degrades the site’s aesthetic quality. However, scientists now say slash creates many positive effects as well. Slash often produces a favor¬ able micro-climate for seedling regeneration, provides habitat for certain wildlife species, returns nutrients to the soil, and in some cases reduces soil erosion. A new publication by the Rocky Mountain Station, The Activity Fuel Appraisal Process: Instructions and Examples, General Technical Report RM-83 by Stanley N. Hirsch, David L. Radloff, Walter C. Schopfer, Marvin L. Wolfe, and Richard F. Yancik presents a strategy to systematically evaluate alternative slash manage¬ ment practices. Based on quantitative modeling and decision theory, the appraisal proc¬ ess allows land manager^ to objec¬ tively correlate fuel quantities, adja¬ cent fuel conditions, expected fire occurrence, climate, topography, fire suppression capability, and treatment costs. In the past, these factors were subjectively analyzed, sometimes producing wide variation in treatment for similar situations. For a complete analysis of residue and fuel management needs, land managers must add to the ‘‘Fuel Ap¬ praisal Process” other treatment costs and benefits — wildlife habitat impact, erosion control, aesthetic enhancement, and regeneration improvement. While the ‘‘Fuel Appraisal Process” does not provide the bottom line in analyzing the economics of alter¬ native slash fuel treatments, it does provide needed fire hazard inputs. If you would like more information write the Rocky Mountain Station and request the publication mentioned. 17 Effects of surface mining As the Nation searches within its own boundaries for new sources of minerals, reclamation of surface mined areas is a primary concern to many land managers. A new publica¬ tion issued by the Intermountain Sta¬ tion can help alleviate that concern. The publication, Environmental Ef¬ fects of Surface Mining of Minerals Other Than Coal, General Technical Report INT-95-FR27, is an annotated bibliography and report on the state of the art of lessening adverse ef¬ fects of such mining. It was collected from various sources including com¬ puterized data bases, personal litera¬ ture collections, and the results of a national survey. Compilers are Bland Z. Richardson, research forester, and Marilyn Marshall Pratt, lead techni¬ cian, both located at the Intermoun¬ tain Station’s Forestry Sciences Laboratory in Logan, Utah. To obtain as much current informa¬ tion as possible, Richardson and Pratt sent inquiries to some 340 knowledgable people. They asked for comments based on professional experience and research on environ¬ mental problems related to surface mining and for citations, publications, and reports on current research. In¬ quiries were sent to mining associa¬ tions; to people presently conducting research on reclamation of surface mines; to environmental concern groups; and to all States’ depart¬ ments or divisions involved in reclamation of surface mines. The respondents’ citations were cata¬ loged and their comments recorded. The annotated bibliography lists nearly 800 citations grouped by general problem subjects, including effects on water, land use planning and public policy, effects on vege¬ tation, and economic and legal aspects. The publication includes a cross- reference index of environmental ef¬ fects of surface mining. For example, it lists citations that describe specific problems and the citations that de¬ scribe solutions to those problems. Richardson says the bibliography will be maintained as an active comput¬ erized file, and supplements will be published from time to time. Copies of this comprehensive bibliog¬ raphy are available from the Inter¬ mountain Station. What causes wetwood? Wetwood is the heartwood of a tree filled with fluid produced by a dis¬ ruption in the tree's physiological processes. It differs from normal heartwood in physical and chemical properties. It smells bad. It requires more time and energy to dry. And lumber and wood products produced from wetwood are more likely to develop ring failure and other defects. The cause of wetwood is not known, and little research has been done to find out. It is thought that a combina¬ tion of factors may initiate disruption of physiological processes that result in wetwood. Bacteria have been found in wetwood, but it is not known whether they are the cause or a result of the condition. There is sub¬ stantial evidence that tree injuries are implicated. Wetwood is found in both conifers and hardwoods. It is generally preva¬ lent in hemlocks, true firs, poplar, and aspen. It occurs in many other species to varying degrees. Douglas- fir is one of the few species that are seldom affected. Trees with frost cracks and scars and knots with watery exudate show symptoms of wetwood. They will produce less utilizable wood than trees without these symptoms, and the wood will take from 2 to 4 times more energy to dry. The condition does not im¬ prove; it can only get worse and in¬ crease processing problems. A new publication from the Pacific Northwest Station pulls together what is known about wetwood and recom¬ mends a program of multidisciplinary research to find its cause and ways to control or prevent it. Copies of Wetwood in Trees: A Timber Resource Problem by J. C. Ward and W. Y. Pong, General Tech¬ nical Report PNW-1 12, are available from the Pacific Northwest Station. Growing wildland shrubs Many disturbed sites in the West can be reclaimed by topsoiling, irrigation, and other measures, but the bottom line is that it is often prohibitively expensive. One alternative is to establish vigorous self-sustaining conditions similar to native ecosys¬ tems. This alternative, however, means that reclamation specialists need information on a wide variety of native and domestic plants in a wide variety of environments. A report issued by the Intermoun¬ tain Station contains information on wildland shrubs that should be valu¬ able to the reclamation specialists. Kimery C. Vories, engineer in charge of environmental programs for two mines in Missouri, compiles existing germination and plant propagation in¬ formation for people planting native or naturalized Colorado shrubs. Although the emphasis is on plants in Colorado, many of the species are also found in the Intermountain and Rocky Mountain regions, as well as in parts of the Pacific Northwest. The report includes information on the seed procurement, pretreatment, laboratory germination, and culture of 127 Colorado shrub species. It also contains 234 literature citations, a list of the Colorado shrub species that have been evaluated by USDA Soil Conservation Plant Materials Centers, and the addresses of plant materials centers in the western United States. In addition, the report lists the commercial suppliers of Col¬ orado shrub seed, seedlings, and transplants, and the addresses of commerical suppliers of Colorado shrubs. Copies of Growing Colorado Plants from Seed: A State of the Art, General Technical Report I NT-1 03- FR27, are available from the Inter¬ mountain Station. A common language for fire behavior Research publications on fire effects and discussions among investigators reveal a serious problem: seldom is a subject fire described in measurable terms. Two Forest Service scientists have proposed a way to correct the problem — standardized methods to describe fire behavior. Dick Rothermel, project leader of the Intermountain Station’s research work unit concerned with fire behav¬ ior, and John Deeming, research forester with the Pacific Northwest Station, discuss these methods in a report issued by the Intermountain Station. Rothermel and Deeming say that, as a consequence of using nonstandard qualitative descriptors, knowledge of fire behavior and fire’s effects is of limited value because it is very dif¬ ficult, if not impossible, to correlate and communicate results of different studies. The scientists have selected fire characteristics that are intuitively related to certain fire effects, and show ways to derive those character¬ istics from simple field observations. The descriptions are written for scientists not usually involved in fire studies, who will be designing and conducting experiments, and for fire researchers who need a system for predicting fire effects. Write to the Intermountain Station for a copy of Measuring and Interpreting Fire Behavior for Correlation with Fire Effects, General Technical Report I NT-93-FR27. Producing plywood and particleboard from Black Hills ponderosa pine Wood product manufacturers in Wyoming and South Dakota may have new opportunities to utilize ponderosa pine timber and residues from wood processing operations in the Black Hills. Information on the feasibility of pro¬ ducing plywood and particleboard in Wyoming and South Dakota is avail¬ able in two publications from the Rocky Mountain Station: Potential for Producing Ponderosa Pine Plywood in the Black Hills, Resource Bulletin RM-4, by Dennis M. Donnelly and Harold E. Worth; and Economic Potentials for Particleboard Produc¬ tion in the Black Hills, Resource Bulletin RM-5 by Donald G. Mark- strom and Harold E. Worth. The Resource Bulletins are a new series of publications by the Rocky Moun¬ tain Station devoted to economic studies of natural resources. The available supply of ponderosa pine saw timber and, particularly, a substantial volume of processing res¬ idues are not fully utilized at present. Economically and environmentally, plywood and particleboard production may offer attractive alternatives for utilizing the sawtimber surplus and mill residues. Scientists and economists estimate the supply of ponderosa pine timber in the Black Hills meeting the re¬ quired size and quality for plywood, is adequate to serve both the present lumber industry and a new plywood plant, at least until 1986. However, after 1986, sawtimber supplies may not be sufficient to support both industries if the existing lumber in¬ dustry regains former production levels. Interest in particleboard production stems from several factors — left¬ over residues from primary and secondary wood processing opera¬ tions; tightened burning restrictions making disposal of excess residues difficult; compatibility with existing Black Hills industries; and outlets for an excess of small roundwood, re¬ moval of which improves forest qual¬ ity and management. The north central U. S. would prob¬ ably be the prime market for Black Hills plywood and particleboard. Not only is there a great demand for these wood products in this area, but Black Hills producers also have lower rail and truck freight costs to that area than western and southern producing regions. Studies show the five principal market categories for plywood in¬ clude residential and nonresidential construction, industrial, distribution (i.e., repair and remodeling), and miscellaneous (international, govern¬ ment, and military markets). Economists have divided markets for particleboard into two groups; con¬ struction and industrial, with a higher proportion being used by industry. For more information, write the Rocky Mountain Station and request the publications mentioned earlier. Controlling tree diseases in the Great Plains Pines and junipers are widely used in the Great Plains for a variety of purposes — protection of soil, crops, wildlife, livestock, and homesteads, wildlife habitat, landscaping, and windbreaks. A recent publication, Pine and Juniper Diseases in the Great Plains, General Technical Report RM-86, by Glenn W. Peterson, plant pathologist at the Rocky Mountain Station's Lin¬ coln, Nebraska lab, summarizes research on five diseases of pines and three diseases of junipers. Great Plains land managers, property owners, and others should find this publication useful because it em¬ phasizes identification, control, and geographic distribution of diseases. In addition, physiological and mor¬ phological information on pathogens is included for researchers working with pathogens in labs. If you would like a copy of Pine and Juniper Diseases in the Great Plains, write the Rocky Mountain Station. Prescribed burning reviewed in report Prescribed burning — the use of fire under carefully prescribed weather and fuel conditions — is “a wildland management tool whose time has come,” according to Range Scientist Lisle R. Green of the Pacific South¬ west Station’s Forest Fire Laboratory in Riverside, California. Green has briefly summarized the results of more than 20 years of research and experience with prescribed fire in his new publication, Burning by Prescrip¬ tion in Chaparral, General Technical Report PSW-51. Although his empha¬ sis is on the use of prescribed fire in California’s 20 million acres of chaparral ecosystems, the informa¬ tion in the Report is also applicable to other Western States as well, where such chaparral species as manzanita, scrub oak, and ceanothus occur. Green reviews what he regards as “the main concerns of the pre¬ scribed burn manager,” including the procedures necessary to plan, carry out, and evaluate a prescribed burn. The recommendations that he pre¬ sents are designed “to guide decisionmaking at each step of the prescribed burn procedure.” This procedure “begins long before the fire is lit, and does not end until long after the fire is out,” he says. Perhaps the most time-consuming step is preparing the burn plan, which should be a statement of the objectives of the prescribed burn, the location and estimated size of the fire, the target date, the proposed ignition technique, and the manpower and equipment needed. Green ex¬ plains how to write the prescription, how to conduct a test burn, and how to follow with the prescribed burn and post-fire appraisal. Included in his discussion is information on fuel moisture, fuel volume, and the in¬ fluence of topography, time of day, season, weather, and the chemical content of the plants. He also talks about smoke management, and de¬ scribes the Federal and State of California air quality regulations that apply to forest or brushland burns. Green says his purpose in preparing the Report was to “reinforce the increased emphasis on prescribed burning as an effective technique for reducing the hazardous accumulation of natural fuels, for improving wildlife habitat, or for increasing water yield.” He also points to the suc¬ cessful use of prescribed burning “to reduce undesirable plants, prepare a site for planting of trees or seeding of perennial grasses, or improve ease of access into brush.” Copies of the Report are available from the Publications Distribution Section, Pacific Southwest Station. 20 ★ U S GOVERNMENT PRINTING OFFICE: 1981-781-143/470 Mountain pine beetles and lodgepole pine— A compatible relationship The mountain pine beetle has killed millions of trees in the United States and Canada. During epidemics, one National Forest may lose more than a million trees in a single year. But the mountain pine beetle and lodge- pole pine have evolved into an inten¬ sive and highly compatible relation¬ ship. Consequently, stand dynamics of lodgepole pine is a primary factor in the development of beetle epidemics. Research focusing on the population dynamics of the mountain pine beetle in lodgepole pine forests is carried out by researchers of the In¬ termountain Station. Project Leader Walter Cole and Principal Entomolo¬ gist Gene Amman have documented a phase of their efforts in Mountain Pine Beetle Dynamics in Lodgepole Pine Forests, Part I: Course of an In¬ festation, General Technical Report INT-89-FR27. In the report, the scientists discuss how the beetle “moves through” the stand, with emphasis on relationships between the beetle and its environ¬ mental factors. The paper represents much original research by Cole and Amman, but it is also a review of other published literature about the mountain pine beetle, with particular reference to epidemic infestations. Write to the Intermountain Station for copies. Aerial photos help rate risk of tussock moth defoliation Forest managers can use aerial photographs to determine which stands are most likely to be defoli¬ ated by the Douglas-fir tussock moth. A new publication from the Pacific Northwest tells how. The process in¬ volves measuring factors that affect the susceptibility of stands to tussock moth defoliation and assigning the stands to five classes of risk based on these measurements. Variables that affect the susceptibility of stands to tussock moth defolia¬ tion — aspect, slope, elevation, topo¬ graphic location, radiation index, stand purity, and crown diameter and density — can be measured by some¬ one skilled in photo interpretation. Instructions for interpreting variables, a list of equipment needed, tem¬ plates, and regression equations are provided. The equations that rate the risk of defoliation were developed from data collected in the Blue Mountains of eastern Oregon and Washington and are generally applicable to those areas. Slightly modified models have also been used successfully in north¬ ern Idaho and can probably be ap¬ plied elsewhere — especially if sup¬ plementary stand data is available. Copies of Rating the Risk of Tussock Moth Defoliation Using Aerial Photo¬ graphs by Robert C. Heller and Steven A. Sader, Agricultural Hand¬ book No. 569, are available from the Pacific Northwest Station. Watch for the next issue of Forestry Research West. You’ll read about a new ecological classification system for southwestern forests; how scien¬ tists are finding better ways for managing Sierra Nevada coniferous forests; review several new research publications; plus moie. 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 21 5C oo 9i oo cd c: 00 CD <*> CO O O T1 DO O -&■ 3. o O :> O CD = CO Z3 CO “0 O O ri 00 9.-0 O CD 5 S Q. 00 oo 5 O CD cn — DO CD < 30 o' 3 < ® § 30 '* m o (/) r; m *s is Is m (/>