Introduction 



Lodgepole pine (Pinus aontorta Doug].) occupies 5.4 million acres in Montana (Wil- 

 son and Spencer 1967) . This vast resource received limited commercial use until the 

 early 1950 's; since then, cutting for poles, pulp, and lumber has increased to an 

 estimated 7,000 acres annually.-^ 



Herbaceous growth develops after clearcutting and provides a potentially important 

 grazing resource for approximately 20 years while the new timber stand is developing. 

 Livestock and game animals now graze some clearcut areas, but the grazing potential 

 appears to be considerably underutilized. This incomplete use is the result of several 

 administrative factors, chief among which are a limited knowledge of the grazing re- 

 source, and a tendency to ignore it because of its transitory nature. 



Efficient management of these ranges depends largely upon our ability to predict 

 the expected composition, yield, and persistence of forage on clearcuts from selected 

 environmental factors. Findings from a study aimed at providing the basis for predic- 

 tion are presented here. 



Methods 



FIELD AND LABORATORY METHODS 



This study was limited to unthinned, lower elevation (below 7,500 feet) clearcut- 

 and-burned areas in Montana, east of the Continental Divide. Twenty-five clearcut 

 sites within the Lewis and Clark and the Gallatin National Forests were selected to rep- 

 resent a range in post-clearcut ages (2 to 17 years had elapsed since cutting) and a 

 variety of aspects. 



On each of these sites, the percentage of aerial crown cover was estimated for 

 each understory plant species within thirty circular plots which were 4.8 sq. ft. in 

 size and distributed in a random pattern over a 1-acre macroplot. All herbaceous vege- 

 tation within the circular plots was clipped at ground level near the end of the grow- 

 ing season, dried at 60° C. for 24 hours, and weighed. The center of each circular 

 plot served also as the center of a milacre plot for data on tree regeneration. 



Physical and chemical characteristics of the A and B soil horizons were determined 

 from samples taken from two soil pits on each of the 25 sites. 



We approximated site index for lodgepole pine for 19 of the 25 sampled sites from 

 measures of site index, as described by Alexander (1966), on immediately adjacent, un- 

 cut stands that closely matched the clearcut areas in soils and topographic features. 



From files of USDA Forest Service, Northern Region, Missoula, Montana. 



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