Fire, followed by an excellent growing season, stimu- 

 lated a large increase in herbaceous biomass production. 

 On inventoried plots in Manning Basin, the forbs, from a 

 prebum base of 85 lb/acre (95 kg/ha), increased almost 

 eightfold in the first postbum growing season and, in the 

 second, about fifteenfold, to 1,254 lb/acre (1,405 kg/ha). 

 Grass production increased from 280 lb/acre (315 kg/ha) 

 to 646 lb/acre (724 kg/ha) in the first year and to 516 lb/ 

 acre (578 kg/ha) in the second. The shrub component was 

 reduced as dramatically as the forb component increased. 

 (Brown and DeByle, in preparation, and unpublished data 

 on file at the Intermountain Fire Sciences Laboratory, 

 Forest Service, Missoula, MT.) 



The forb species that dominated the postburn vegeta- 

 tion were not those sampled extensively in this study. A 

 globemallow (Iliamna rivularis) that was not found prior 

 to burning was the most abundant forb on these sites 

 afterwards. Fireweed {Epilohium angustifolium) was also 

 common on the burned areas but was nonexistent on the 

 control areas. Both of these forbs were sampled in the 

 second year. They had digestibilities over 80 percent 

 throughout the second summer. Crude protein levels 

 were also high, averaging 20 percent for fireweed and 18 

 percent for mallow. Wherever cattle and sheep grazed on 

 the burned sites, these two forbs were highly preferred, 

 ofi;en grazed to ground level. This was especially true in 

 the first postbum year when these plants were quite suc- 

 culent. Thus, burning introduced highly preferred and 

 nutritious forages that otherwise would not have occurred 

 on these sites. Free-ranging tame elk preferred the 

 burned sites in the second and third summers after treat- 

 ment. The composition and quality of their chosen diets 

 are reported by Canon and others (1987). 



CONCLUSIONS 



The benefits of these prescribed fires to ruminants, both 

 wild and domestic, are substantial during the summer 

 and autumn of the first several postburn years. Our 

 bums provided a more nutritious forage resource than 

 before, when shrubs dominated these sites. Forage also 

 became more accessible because dense shrub motts were 

 reduced. The height of forage, after burning, was totally 

 within the grazing zone, in contrast to unbumed sites 

 dominated by shrubs, where much of the biomass often is 

 above the reach of grazing ungulates. Thus, on these 

 bumed areas, animals could obtain a high-quality diet 

 with relative ease (Canon and others 1987). 



Generally, with or without burning, the nutritive qual- 

 ity of aspen understory is high (Collins and Umess 1983, 

 Canon and others 1987). The quality of our selected spe- 

 cies improved only in the first postburn year. Wood 

 (1988) found similar transient improvement in pine 

 understory in South Carolina. In our study, we found 

 that few species dropped below 50 percent digestibility 

 even in late September. The shrubs averaged about 14 

 percent crude protein for all dates. The grasses and some 

 of the forbs decreased to about 7 percent crude protein in 

 late September, but still within the maintenance require- 

 ments for at least adult mule deer (Dietz 1965). All of the 

 plants were still green and growing in September. 



Prescribed burning increased forage quality of species 

 that were common to both burned and adjacent unbumed 

 sites, but only briefly. By the second postburn year, the 

 quality of most forages did not differ significantly between 

 treatments. Despite the inconsistent and transient im- 

 provement in quality of individual forage species, pre- 

 scribed buming remains a useful tool to alter forage spe- 

 cies composition and forage availability in the aspen-tall 

 shrub community. 



REFERENCES 



Allen, S. E.; Grimshaw, H. M; Parkinson, J. A.; Quarby, 

 C. 1974. Chemical analysis of ecological materials. 

 New York: John Wiley Sons; Halsted Press. 565 p. 



Association of Official Agricultural Chemists. 1965. Offi- 

 cial methods of analysis. 10th ed. Washington, DC. 



Bartos, D. L.; Mueggler, W. F. 1981. Early succession in 

 aspen communities following fire in western Wyoming. 

 Joumal of Range Management. 34: 315-318. 



Blank, D. L. 1984. Forage quality comparison of burned 

 and nonburned aspen communities. Logan, UT: Utah 

 State University. 74 p. M.S. thesis. 



Brown, J. K.; DeByle, N. V. [In preparation]. Effects of 

 prescribed fire on biomass and plant succession in west- 

 em aspen. U.S. Department of Agriculture, Forest Serv- 

 ice, Intermountgdn Research Station, Missoula, MT. 



Canon, S. K.; Umess, P. J.; DeByle, N. V. 1987. Habitat 

 selection, foraging behavior, and dietary nutrition of elk 

 in burned aspen forest. Journal of Range Management. 

 40: 433-438. 



Chapin, F. S., Ill; Van Cleve, K. 1978. Plant nutrient 



absorption and retention under differing fire regimes. 



In: Fire regimes and ecosystem properties. Gen. Tech. 



Rep. WO-26. Washington, DC: U.S. Department of Agi'i- 



culture. Forest Service. 301-321. 

 Collins, W. B.; Urness, P. J. 1983. Feeding behavior and 



habitat selection of mule deer and elk on northern Utah 



summer range. Journal of Wildlife Management. 47: 



646-663. 



Crane, M. F.; Habeck, J. R.; Fischer, W. C. 1983. Early 

 postfire revegetation in a western Montana Douglas-fir 

 forest. Res. Pap. INT-319. Ogden, UT: U.S. Department 

 of Agriculture, Forest Service, Intermountain Forest 

 and Range Experiment Station. 32 p. 



Curtis, J. D.; Partch, M. L. 1950. Some factors affecting 

 flower production on Andropogon gerardi. Ecology. 31: 

 577-578. 



DeByle, N. V.; Bevins, C. D.; Fischer, W. C. 1987. Wildfire 

 occurrence in aspen in the interior western United 

 States. Western Journal of Applied Forestry. 2: 73-76. 



Dietz, D. R. 1965. Deer nutrition research in range man- 

 agement. Transactions of the North American Wildlife 

 and Natural Resources Conference. 30: 274-285. 



Ehrenreich, J. H.; Ackman, J. M. 1963. Effect of burning 

 on seedstalk production of native prairie grasses. Pro- 

 ceedings, Iowa Academy of Sciences. 64: 205-212. 



Hadley, E. B. 1970. Net productivity and buming re- 

 sponses of native eastern North Dakota prairie commu- 

 nities. American Midland Naturalist. 84: 121-135. 



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