A 1967 thinning operation on the north slope showed grand fir, western redcedar, 

 western larch, and western hemlock favored at 200, 400, and 800 trees per acre. The 

 snow-sample study conducted on the vegetative recovery plot favored western redcedar at 

 400 trees per acre or an average spacing interval of 10x10 ft (3x5 m) . The silvicul- 

 tural prescription calls for thinnings in 1985, 2005, and 2025, with the final harvest 

 in 2045. 1 No silvicultural treatment is planned for the south slope. 



The climate of the Experimental Forest is predominantly under the influence of the 

 Pacific Ocean. Winter storms bring most of the annual precipitation in the form of 

 snow. At the plot elevation (3,500 ft or 1,067 m) , the estimated average annual preci- 

 pitation was 35 to 36 in (84 to 91 cm). At this elevation, thaws are common throughout 

 the winter; hence, the peak snow water equivalents measured from March 1 to April 1 

 underestimate the total winter snowfall. 



Slope gradients on the north slope average 52 percent; on the opposite slope, 

 58 percent. For information on geomorphology and soils and complete data of the bio- 

 logical environment, the reader is referred to R. T. Graham's report. 1 



In 1942 snow courses were established on the west half of the vegetative recovery 

 plot and extended into an adjoining forest plot (fig 1). Snow depth and snow water 

 equivalents (W.F..) were initially taken with a Mt . Rose snow tube and. later, with a 

 federal -type snow sampler. Measurements began at approximately the time of maximum 

 accumulation and continued about weekly through the melt period. This was repeated for 

 13 seasons on the north slope and 6 seasons on the south slope from 1942 through 1974. 



The spacing and number of sample points and the location of snow courses changed 

 during the study period as a result of amendments to the original study objectives 

 (table 1). Tn 1967, the earlier courses were switched to the opposite side of the 

 vegetative recovery plot (fig. 1). Because of expected differences in snow conditions 

 between the east and west recovery-forest boundaries, measurements taken in the vicinity 

 of the border zone were eliminated from the analyses. Data from the sample points for 

 each year were averaged. 



Table I. -Snow course stations (number and approximate spacing in feet) 



PHYSICAL ENVIRONMENT 



METHODS 



North- face 



South-face 



Year 



Strip 

 clearcut 



Timber 



Strip 

 clearcut 



Timber 



1942 

 1949-52 

 1967-73 

 1974 



5-30 

 9-20 

 3-50 

 3-50 



5- 30 



6- 20 

 2-50 

 2-50 



5-30 

 8-20 



3-50 



5-30 

 7-20 



2-50 



4 



