Creating Wildlife Habitat Conditions

Transcription

1 Creating Wildlife Habitat Conditions Dale L Wills TABLE OF CONTENTS INTRODUCTION SUBALPINE FOREST AND DOUGLAS FIR Grass-forb Stage Shrub-seedling Stage Sapling-pole Stage Mature Stage Old-growth Stage Special Habitat Components PONDEROSA PINE Grass-forb Stage Shrub-seedling Stage Sapling-pole Stage Mature Stage Old-growth Stage Special Habitat Components LODGEPOLE PINE Grass-forb Stage Shrub-seedling Stage Sapling-pole Stage Mature Stage Old-growth Stage Special Habitat Components ASPEN Grass-forb Stage Shrub-seedling Stage Sapling-pole Stage Mature Stage Old-growth Stage Special Habitat Components PINYON-JUNIPER Grass-forb Stage Shrub-seedling Stage Sapling-pole Stage Mature and Old-growth Stages Special Habitat Components GAMBEL OAK Grass-forb Stage Shrub-seedling Stage Sapling-pole Stage Mature and Old-growth Stages Special Habitat Components RIPARIAN FORESTS High Elevation Riparian Cottonwood Riparian CONCLUSIONS ACKNOWLEDGEMENTS BIBLIOGRAPHY

2 INTRODUCTION Previous chapters have described forested ecosystems, habitat conditions necessary for selected wildlife species, and various silvicultural practices which can be used to manage forested lands. This Chapter explains how silvicultural practices described in Chapter 4 can be applied to forested ecosystems to develop those habitat conditions necessary to meet wildlife objectives established by the land manager or owner. Habitat conditions are described in terms of structural stages for all of the forested ecosystems except the riparian. Riparian forest ecosystems are discussed in general terms with emphasis on providing vertical diversity. The practicability of providing vertical and horizontal diversity is discussed for all ecosystems. Objectives described in Chapter 7 and a management plan patterned after the exam pie shown in Chapter 8 can be accomplished using the practices described in this Chapter. In most forest ecosystems, forage production in the understory will occur in those stands with less than 40% canopy closure. As the canopy closure increases, forage production declines, with very little, if any, forage production occurring under stands with canopy closures exceeding 70%. This factor must be considered when providing habitats to meet forage requirements of deer, elk, and other herbivores. When developing a management plan, it is necessary to know the expected duration of each structural stage; Table 5-1 shows the estimated duration in years for each structural stage of selected forest ecosystems. It is also important to know the structural stage and the future growth expectation which occur under a particular stand condition. Appendix C contains graphs showing the expected growth rates and approximate structural stage for 9 initial stocking rates of spruce-fir, Douglas fir, ponderosa pine, lodgepole pine, and aspen. Growing conditions will vary with site conditions and the type and number of intermediate treatments. Table 5-1 and Appendix C can be used collectively to obtain an approximation of when treatments may need to be scheduled in order to provide for the necessary habitat conditions. A management plan will require that prescriptions be developed for the various stands of trees. When developing a management prescription, there are 6 steps that one must go through. These 6 steps are outlined below with examples shown in parentheses. These examples are brought together into a tabular format in Table 5-2 following Step No. 6. (1) Determine the number of acres in the management unit or stand (1,000 acres of lodgepole pine). (2) Determine the age at which the stand will be totally regenerated (the rotation period) and provide an even -flow, sustained yield of the desired habitat conditions. The age at which it should be regenerated will depend upon the amounts of the various structural stages that are required, e.g., if mature trees rather than old-growth are desired, the stand can be regenerated at a much younger age. The percentage of the stand to be maintained in the oldest age class determines the maximum age of the stand in the rotation period. To determine the rotation period necessary to provide for an evenflow, sustained yield of the desired acres of habitat 3 computations are necessary: a. Determine the age at which the oldest desired stage begins (from Table 5-1, old-growth was estimated to begin at 150 years of age; obtained by adding grass-forbs, 10 years; plus shrubseedling, 20 years; plus sapling-pole, 40 years; plus mature, 80 years). b. Determine the percentage of the stand to be in age classes younger than the oldest desired. This is obtained by subtracting the percent of the oldest age class desired from 100 (desire 20% oldgrowth, = 80%). c. Divide the age determined in Step 2a., above (150), by the percentage obtained in Step 2b., above (80%), to determine the rotation period, ( = rounded up to 190). (3) Determine the number of years between treatment entries (10 years) and the corresponding number of entries needed to totally treat the stand. The latter is obtained by dividing the rotation period by the treatment interval (190 10=19 entries to totally regenerate the stand and continuously provide 20% old-growth). (4) Determine the number of acres that need to be treated in each period or entry by dividing the total acres to be managed by the number of entries (1,000 acres 19 entries=53 acres treated each 10 years). (5) Determine the treatments necessary to provide the necessary structural stages (clearcutting of lodgepole pine will provide grass-forb stages and regenerate the stand to provide an even flow, 245

3 sustained yield of the necessary habitat conditions). Other options are also available. (6) Should other than naturally occurring canopy closures be desired, an additional step is needed. This step is the addition of silvicultural practices necessary to create the desired conditions. For example, should the objective be to maintain 10% of the mature stands with a canopy closure of 40 to 70%, an initial prescription would call for intermediate cuts to remove approximately 40% of the canopy in 2 entries at 10- year intervals. Treating 10% of the area by removing 20% of the original canopy with each entry would achieve the objective in 20 years. Subsequent treatments would need to be adjusted based on growth rates and when the thinned stand was scheduled for regeneration. The development of the initial and subsequent treatments must be done by a knowledgeable silviculturist who can prevent such problems as windthrow, insect infestations, and disease. If wildlife objectives can be expressed in terms of acres and kinds of habitat, experienced foresters can develop management prescriptions that will provide the necessary habitat conditions. large portion of the older trees. The use of a trained silviculturist can assure the development of proper management prescriptions that will meet wildlife habitat objectives with the proper silvicultural treatments. Although the process outlined above provides a simple method by which to determine how many acres need to be cut on each entry in order to provide an even-flow, sustained yield of various habitats, one important element - - th e age of the existing stand -- is lacking. If the existing stand is mature or over mature, it may be necessary to modify the schedule to prevent the loss of a 246

4 CONCLUSIONS Various methods have been presented in this Chapter to create desired structural stages and canopy closures for wildlife. When the land manager decides to create a particular stand structure or habitat condition, additional decisions must also be made. For example, should the desired habitat conditions be perpetuated over time in a specific location or should the conditions rotate through time over a large area? In some cases, such as the need to provide habitat conditions consisting of seedling, pole, and mature forest conditions, it is most logical to let the stand rotate through time. Allowing the conditions to rotate is usually less costly than trying to permanently maintain the stand structure on a specific site. The land manager must also decide which silvicultural method will be most effective in creating or maintaining the desired stand structure. The choice of stand structure and the methods used to achieve it are determined by the management objectives established by the land manager. Wildlife species will use forested habitats as long as the necessary habitat components are provided. They are not particular about which practices are used to create or maintain habitat conditions, only the end results. ACKNOWLEDGEMENTS The material for this chapter was developed by foresters and wildlife biologists, using selected references and their personal experiences, in a workshop session held in Fort Collins, Colorado, April 1-11, Participants included Phil Anderson, David E. Blackford, Marc L. Bosch, Thomas L. Cartwright, Darrell W. Crawford, Robert H. Frye, Gerald J. Kowalski, Ronald J. Krager, Curtis J. Orde, Michael J. Paterni, and William Shuster of the U. S. Forest Service; and Steven J. Bissell, Harvey S. Donoho, Patsy Goodman, Walter D. Graul, Robert D. Hernbrode, Richard W. Hoffman, William H. Rutherford, Warren D. Snyder, Peggy Svoboda, and Robert K. Towry, Jr. of the Colorado Division of Wildlife. The contributions made by these workshop participants is gratefully acknowledged. The author also acknowledges the contributions of Robert J. Jackson and Milo J. Larson, timber management staff members, Rocky Mountain Region, U.S. Forest Service. 256

5 BIBLIOGRAPHY Alexander, R. R Partial cutting in old-growth spruce-fir. USDA For. Servo Res. Pap. RM pp Partial cutting practices in old-growth lodgepole pine. USDA For. Servo Res. Pap. RM pp. Brown, H. E Gambel oak in west-central Colorado. Ecology 39(2): Gullion, G. W Aspen management activity report. USDA For. Serv., Reg. 2, Denver. 31 pp. Processed. Horton, L. E An abstract bibliography of Gambel oak (Quercus gambelii Nutt.) USDA For. Serv., Reg. 4, Ogden, Utah. 64pp. Lanner, R. M Pinyon pines and junipers of the southwestern woodlands. Pages 1-17 in The pinyonjuniper ecosystem: a symposium. Utah State Univ., Agr. Exp. Sta., Logan. 194pp. Myers, C. A Growing stock levels in even-aged ponderosa pine. USDA For. Servo Res. Pap. RM pp Multi-purpose silviculture in ponderosa pine stands of the Montane zone of central Colorado. USDA For. Servo Res. Pap. RM pp. Patton, R., and R. Jones Managing aspen for wildlife in the southwest. USDA For. Servo Gen. Tech. Rep. RM-37. 7pp. Pearson, G.A Management of ponderosa pine in the Southwest. USDA Monogr. No pp. Short, H. L., and C. Y. McCulloch Managing pinyon-juniper ranges for wildlife. USDA For. Servo Gen. Tech. Rep. RM pp. Steinhoff, H. W Management of Gambel oak associations for wildlife and livestock. USDA For. Serv., Reg. 2, Denver. 119pp. USDA Forest Service Stand characteristics to meet the major uses of aspen. USDA For. Serv., Reg. 2, Denver. 171 pp. Processed. West, N. E., R. J. Tausch, and A. A. Nabi Patterns and rates of pinyon-juniper invasion and degree of suppression of understory vegetation in the Great Basin. USDA For. Serv., Intmtn. Reg., Ogden, Utah, Range Imp. Notes, Sept. 14pp. 257

6 MANAGING FORESTED LANDS FOR WILDLIFE Developed in cooperation with U.S. Department of Agriculture, Forest Service, Rocky Mountain Region Robert L. Hoover and Dale L. Wills, Editors Published By COLORADO DIVISION OF WILDLIFE 1987 CONTRIBUTIONS Administrators, biologists and foresters in the Colorado Division of Wildlife and the Rocky Mountain Region of the U.S. Forest Service have joined forces in a unique effort to provide this book. The work of 15 authors from the Division of Wildlife and the Forest Service has been supported by the advice and counsel of many others in these two organizations as well as other institutions and agencies. Information provided by scientists in previously published records has been of immeasurable value in preparation of this book and in advancement of our knowledge on management of forested ecosystems for the benefit of wildlife. The book is out of print. This excerpt was electronically reproduced by Colorado State University Cooperative Extension January, 2005