Each of the 16 compartments was also divided into three initial volume classes. 

 These three volume classes, which occupied a minimum of 10 acres in each compartment, 

 were: 



Volume Initial volume 



class Bd. ft. per acre 



I - 10,000 



II 10,000 - 20,000 



III 20,000 or more 



Logging reduced each initial volume class to two levels of reserve volume as follows: 



Volume High reserve Low reserve ' 



class Bd. ft. per acre 



I 6,000 4,000 



II 11,000 8,000 



III 18,500 14,500 



Very little logging was possible in volume class I because the initial volumes were so 

 low; therefore, that class was eliminated from the analysis of logging damage. 



Sampling Scheme 



The damage to advance growth consisted of the reduction in stocking caused by 

 logging. This reduction in stocking was measured in two ways: first, by the reduction 

 of stocked quadrats; and second, by the reduction of poles per acre. 



In the first measurement of damage, stocking of seedlings, saplings, and poles 

 was measured on 293 sample plots located randomly in each volume class of each compart- 

 ment at the rate of one plot for each 2 acres within the given volume class. Each 

 sample plot contained 40 milacre quadrats on which the stocking of seedlings, saplings, 

 and poles was determined. The presence or absence of at least one tree was recorded 

 to determine whether that quadrat was stocked. 



The second measurement of damage, reduction of the number of poles per acre, was 

 taken at the same 293 sample plot locations as the quadrat stocking. The number of 

 poles on an 0.08-acre plot was recorded at each location. 



Data from measurements of these plots 1 year before logging and 2 years after log- 

 ging were the basis of the study of logging damage reported here. 



RESULTS 

 Quadrat Stocking 



The average percentage of quadrats stocked with seedlings, saplings, or poles 

 before logging, after logging, and destroyed by logging was computed for the four vari- 

 ables: tractor size, reproduction method, reserve volume, and initial stand volume 

 (table 1) . Preliminary analyses showed that reduction in stocking was directly corre- 

 lated with original stocking. Therefore, adjustments were made by the method of 

 covariance analysis before analyzing the effect of the four variables on logging damage. 



The level of reserve volume, or the intensity of cut, was the only treatment that 

 significantly affected logging damage to quadrat stocking. Logging damage resulting 

 from heavy cutting (low level of reserve) approached twice that from light cutting 

 (high level of reserve). Heavy cutting required more trips by the skidding tractors 

 to remove more logs. As a result, this cutting reduced the average quadrat stocking 



2 



