LOWER SANDS 

 CREEK STUDY 



Eistablishment 



This study was also located in the Sands Creek drainage, but on the lower part of 

 the northerly slope. The area was logged-over for western white pine about 1916, 

 leaving a residual stand of defective grand fir and western hemlock. As a result of 

 the logging disturbance, more than 18,000 seedlings per acre, many of them white pine, 

 became established. During the following 18 years, expanding crowns of the residual 

 overstory trees reduced the average amount of light available to the seedlings to about 

 25 percent of full sunlight. Western white pine still persisted, but the species was 

 becoming increasingly overtopped by the more shade-tolerant grand fir and hemlock. 



In 1935, two silvicultural measures were employed on half of ♦the area to release 

 the white pine and western redcedar regeneration which then averaged about 15 years old. 

 First, the overstory was removed by girdling the trees over 20 inches in diameter and 

 felling the smaller ones. Secondly, competing grand fir and hemlock seedlings were 

 removed by a cleaning operation. This reduced the number of seedlings by 80 percent 

 to about 3,500 per acre. Neither overstory removal nor cleaning was done on the remain- 

 ing half of the area. 



Two 0.1-acre sample plots were installed in each half in 1935, and these were 

 remeasured in 1940, 1945, 1950, 1955, and 1965. Tree counts and height measurements 

 were made each time. Beginning in 1945, stocking information by 1- and 4-milacre 

 quadrats was also obtained. 



Results 



Under the heavily-shaded conditions of the unreleased check plots, western white 

 pine was nearly eliminated from the reproduction stand by suppression during the 30-year 

 period of observation (fig. 5). Even grand fir suffered considerable attrition, 

 dropping from 25 percent of the stand at the beginning of the study to less than 

 10 percent at the end. Western hemlock, on the other hand, continued to increase both 

 in numbers and size. Measurements taken on 4-milacre sample quadrats revealed that over 

 three-fourths of the quadrats were dominated by hemlock at the last examination. 



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