others. Additionally, stands that are not 

 technically old may possess many important 

 old-growth components, serving the old- 

 growth function better than some actual old 

 stands and, thus, should be considered as 

 potential replacement old-growth stands. 



1.- 



I 



The intent of the SFLMP is to maintain enough 

 old growth to meet the specified old-growth 

 commitment, but not drop bejow that amount. 

 The at-least-half amount represents the naini- 

 mum DNRC has committed to retaining, but 

 does not necessarily represent the maximum 

 desirable for retention. .• , ..?, 



ANALYSIS AREA 



In the old-growth analysis, historic conditions 

 will be displayed from the scale of Climatic 

 Section 333C, which represents the Upper 

 Flathead Valley. Current and appropriate 

 conditions will be displayed on the scale of the 

 contiguous Stillwater State Forest, approxi- 

 mately 91,119 acres. 



e remsiiLvw 



OLD-GROWTH 

 COMMITMENTS 



Stands with a substantial overstory compo- 

 nent of 150 years old and older are considered 

 old -giT'Vv'rh svands in this analysis. The excep- 

 tions are lodgepole pine stands, which were 



sorted as old stands if they were 140 years old 

 or older. Table 111-5 shows that approximately 

 34,244 acres, approximately 38% of the entire 

 Stillwater State Forest analysis area are cur- „ 

 rently considered old-growth stands. The 

 1930s' data from the Upper Flathead Valley 

 indicates that old stands occupied approxi- 

 mately 29% of the area. Proportions of old | 

 growth on Stillwater State Forest exceed the "; 

 one-half historic commitment in all cover ! 



types, with the exception of the western larch/ 

 Douglas-fir cover type, which is now approxi- 

 mately 381 acres below the minimum. Cur- - • 

 rently, there is one timber sale on Stillwater 

 State Forest (Upper Stryker Ridge II Timber „ 

 Sale) being harvested that will likely convert 

 several hundred acres of old-growth stands 

 with a mixed<onifer cover type directly to 

 old-growth stands with a western larch/ 

 Douglas-fir cover type. This will be accom- 

 plished by harvesting many of the shade- '""™' 

 tolerant and retaining many older large west-; 

 em larch and Douglas-fir. -^ 



The SFLMP calls for the maintenance of ' ci 

 sufficient acres to replace old stands that may 

 fall apart, die, or bum. The proportions were 

 calculated using a Weibull function for age- 

 class distribution. The Weibull function uses t 

 both the fire-return interval and a shape 

 parameter to fit the age-class curve. This 

 curve indicates the proportion of stands 

 needed in each age class in Stillwater St^te 

 Forest. Table III-6 shows the cover types and 



A i 



TABLE nZ-5 - DNRC OLD-GROWTH RETENnON COMMTTMENTS ON STILLWATER STATE FOREST 



Chapter III: Affected Environment 



'111-7 



