Animal community

Wildlife Interpretations:
Quaking aspen forests provide important breeding, foraging, and resting habitat for a variety of birds and mammals. Wildlife and livestock utilization of quaking aspen communities varies with species composition
of the understory and relative age of the quaking aspen stand. Young stands generally provide the most browse. Quaking aspen crowns can grow out of reach of large ungulates in 6 to 8 years. Although many animals browse quaking aspen year-round, it is especially valuable during fall and winter, when protein levels are high relative to other
browse species.

Livestock Interpretations:
This site is suited to cattle and sheep grazing during the summer and early fall. Livestock use quaking aspen communities for forage and shade. Cattle select for understory grasses while sheep tend to select for forbs. Browsing has a direct impact on aspen. Through the early sapling stage, browsing reduces aspen growth, vigor and numbers. Heavy browsing by sheep or deer can eliminate aspen sucker regeneration. Suckers can be drastically reduced or eliminated by big game browsing on winter ranges. Sheep browse the aspen with increasing pressure through late summer and early fall. Browsing is incidental to grazing by cattle. If cattle grazing is light to moderate, the impact on aspen will also be slight. This relationship, however, is less true for sheep and wild ungulates. Aspen saplings need to attain a minimum height of 55 to 60 inches to avoid destructive browsing by livestock. Harvesting trees under a sound management program for fuelwood, posts or other products, can open up the tree canopy to allow increased production of understory species desirable for grazing and browsing.

The forage value rating is not an ecological evaluation of the understory. The forage value rating is a utilitarian rating of the existing understory plants for use by specific kinds of grazing animals.

Stocking rates vary over time depending upon season of use, climate variations, site, and previous and current management goals. A safe starting stocking rate is an estimated stocking rate that is fine tuned by the client by adaptive management through the year and from year to year.

Example: Sample Calculations using Favorable Year production amounts:

500 lbs of available forage/ac x. 25 (Harvest Efficiency) = 125 lbs forage consumed

125 lbs/790 lbs = .16 AUMs/ac or 6.32 ac/AUM

NOTE: 790 lbs/month for one Animal Unit is used as the baseline for maintenance requirements. This equates to 30 lbs/day of air-dry forage (1000 lb cow at 2.6% of body weight). See NRCS National Range and Pasture Handbook.

Hydrological functions

Mountain slopes covered by quaking aspen provide high yields of good-quality water. Quaking aspen intercepts less snow than conifers, so snowpack is often greater under quaking aspen. Well-stocked quaking aspen stands provide excellent watershed proctection. The trees, the shrub and herbaceous understories, and the litter of quaking aspen stands provide nearly 100 percent soil cover.

Recreational uses

Aesthetic value is derived from the rich hues and textures of the aspen trees, particularly in the fall. The diverse flora and fauna, and the colorful wildflowers in the summer enhance the beauty of this site. The site offers rewarding opportunities to photographers and for nature study. It has high value for hunting, camping, picnicking, cross country skiing and family wood gathering. Management of the aspen woodland should include small, irregularly shaped clearcuts that blend into the natural landscape. Harvesting plans should include a mix of even-aged aspen patches in all size classes. Aspen fits well into management for dispersed recreation activities, but does not tolerate concentrated use, as found in established campgrounds. Encouraging concentrated recreation or developing campgrounds within aspen stands can lead to serious damage, including carving on trees, vandalism, destruction or removal of young suckers and trampling and disturbance of the soil.

Wood products

Historically quaking aspen has been used for mine props, posts, bridge planking, flooring, furniture and fuelwood. This tree has a considerable potential for increased utilization. It makes excellent pulp, excelsior, door corestock, paper,
particleboard, matchsticks, structural flakeboard, lumber products and boxwood. An Quaking aspen pellets are used for fuel.

MANAGEMENT GUIDES AND INTERPRETATIONS

1. LIMITATIONS AND CONSIDERATIONS
a. Potential for sheet and rill erosion is low to moderate depending on slope.
b. Moderate to severe equipment limitations on sites having a high water table.
c. Proper spacing is the key to a well managed, multiple use and multi-product aspen woodland.
d. To begin short-rotation management, older stands with larger trees need to be harvested.
e. Cut residual unmerchantable trees to stim-ulate maximum sucker regeneration and rapid development of a replacement stand-thin resulting sucker stands.
f. Soil compaction and erosion hazards are greatest if logging is done with heavy equipment when soils are saturated. Logging at this time is most damaging to aspen roots, which can reduce suckering. Root carbohydrate reserves are lowest in the spring and harvesting at this time can further reduce sprouting.

2. ESSENTIAL REQUIREMENTS
a. Adequately protect from high intensity wildfire.
b. Protect soils from accelerated erosion.
c. Apply proper grazing management.

3. SILVICULTURAL PRACTICES
a. Harvest cutting - Selectively harvest surplus trees to achieve desired spacing. Harvest stands in small blocks of 1/5 to 1/2 acre with slash left in place to shelter emerging aspen suckers from browsing.
1)Clear-cutting - Clear-cutting is appro-priate when the primary management objective is sustained production of forest products, either saw timber or fiber. Cutting sub-merchantable stems along with the merchantable ones will maximize sucker production, will minimize the presence of diseased or defective growing stock in the new stand, and will avoid suppression of the new crop by residual overstory stems.
2)Partial cutting - Partial cutting may be feasible in some uneven-aged stands where management objectives require vertical canopy diversity or retention of some overstory; partial cutting may result in enough sprouting to adequately regenerate stands. Individual tree or group selection cutting methods can be applied. Extreme care is necessary to avoid injury to residual stems during logging. Partial cutting is not worthwhile in deteriorated aspen clones where root system die-back has reduced suckering.
3)Selective Tree Removal - Remove selected trees on suitable sites to enhance forage production and manage site reproduction.
b. Thinning - Ordinarily, only stands on saw timber sites should be thinned. Pre-commercial thinning may be uneconomical. The low productivity of this site would not justify thinning costs.
c. Protection from disease - There are no proven forest stand treatments that successfully prevent or control disease in aspen. Maintenance of well-stocked stands, minimizing wounding of stems and control damaging agents, and harvesting at the proper rotation age are the best management recommendations that can be made today.
d. Protection from insects - Direct control of insects in aspen forests has not been practical. The environmental side-effects from chemical pesticide spraying usually has not been acceptable in the aspen ecosystem. Maintenance of a well-stocked stand and protection from wounding is the most practical method of coping with insects in the aspen forest.
e. Protection from mammals - Domestic livestock, wild ungulates, porcupines, rodents and hares utilize aspen as food and can have measurable impacts on some stands. Most animal damage can be prevented by careful husbandry of domestic livestock and by population control of wild game. Because most aspen stands are grazed by cattle and/or sheep and have a significant population of wild ungulates, grazing management and game management are important to aspen communities.
f. Fire management - Fire is a natural feature of the aspen ecosystem. Fire is considered responsible for the abundance of aspen in the west, and for the even-aged structure of many stands. Without human intervention, fire appears to be necessary for the continued well-being of aspen on sites where natural degeneration of the clone occurs, or where insects or pests are especially harmful to the stand. Aspen forests do not readily burn. Fires in aspen generally are infrequent, spread slowly, are of low intensity, and are easy to control. In most areas, the conditions suitable for a fire are infrequent in aspen stands. Although aspen forests do not burn readily, aspen trees are extremely sensitive to fire. Even very light fires will kill aspen, because the bark is thin and green, and lacks protective corky layers. Even with adequate fuels, the flammability of adjacent grasslands may make prescribed burning risky. However, where fire can be used with reasonable safety, it is an inexpensive and effective way to naturally regenerate the aspen forest. Moderate intensity fire that kills most or all the overstory will stimulate adequate suckering and will have the least effect on subsequent sucker growth. If fire occurs at infrequent intervals and is moderately intense to kill most or all of the aspen overstory, most aspen sites will remain viable. Frequent fires may adversely affect site quality.

Other information

An undesirable characteristic of quaking aspen stands is their heavy drain on available water in the soil.

Table 7. Representative site productivity

Type locality

Other references

Airola, D. A. 1980. Northeast Interior Zone: Vol. III - Birds & Vol. IV - Mammals. U.S. Gov. Printing Off.: 1980-690-082/26.

Baker, F. S. 1925. Aspen in the central Rocky Mountain region. USDA, Bulletin 1291, 47 p. Washington D.C.

DeByle, N. V., and R.P. Winokur, editors. Aspen: Ecology and Management in the Western United States. General Technical Report RM-119, Rocky Mtn For & Rng Exp Sta, FS, USDA.

DeByle, N.V., P.J. Urness, and D.L. Blank. 1989. Forage Quality in Burned and Un-burned Aspen Communities. Research Paper INT-404. Inter. Res. Sta., FS, USDA.

Fire Effects Information System[Online], http://www.fs.fed.us/database/feis

Plants Database [Online], http://www.plants.usda.gov

Contributors

ALM

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