J.AMF5 C. SPACB 



from 47.63 percent before logging to 39.28 percent, a reduction of 8.35 percent. Light 

 cutting reduced the average quadrat stocking by only 4.76 percent. This difference be- 

 tween levels of reserve volume proved statistically significant only at the 5-percent 

 level of probability. 



Difference in damage within each of the other three treatments was small and not 

 significant statistically. Logging damage was nearly the same whether the logs were 

 skidded by a large tractor (D-8) or a small tractor (D-4) , when cutting was scattered 

 as in stem selection or concentrated as in group selection, and when the original over- 

 story averaged 10,000 to 20,000 board feet per acre or more than 20,000 board feet per 

 acr e . 



Table 1. -- Effects of logging tractor size, reproduction methods, reserve 

 volumes, and initial volumes on logging damage to stocking of advance 

 reproduction and poles and significance of differences 



Tr ea tment 



Tractor size 

 D-4 

 D-8 



Reproduction 



method 



Stem selection 

 Group selection 



Level of reserve 

 Low 

 High 



Initial volume 

 class 

 II 

 III 



Average percent quadrats stocked Statistical 

 Before After Destroyed by significance 

 logging logging; logging of differences 



Percent 



44.06 

 45.68 



46.74 

 43.01 



47.63 

 42. 12 



41.59 

 48.15 



Percent 



37.41 

 39.22 



39.75 

 36.89 



39.28 

 37.36 



35.47 

 41.17 



Percent 



6.65 

 6.46 



6.99 

 6.12 



8.35 

 4.76 



6.12 

 6.98 



N.S. 



N. S. 



1/ 



N.S. 



All treatments 



44.87 



38.32 



6.55 



1/ *The difference between treatments was statistically significant 

 at the 5-percent level of probability. 



N.S. The differences between treatments were statistically not 

 significant at the 5-percent level of probability. 



Pole Understory 



The second measurement of logging damage concerned only the understory pole stands. 

 Pole damage was measured in term^ of number of poles per acre before logging and the 

 percentage of poles killed by logging. This measurement differs somewhat from the pre- 

 vious measurement of damage in terms of complete elimination of seedlings, saplings, 

 and poles from a specified area, the milacre quadrat. 



The mortality figures showed little or no difference between treatments (table 2). 

 Heavy cutting (low reserve) destroyed 14 percent of the poles while the light cutting 

 (high reserve) destroyed only 10 percent, a difference not statistically significant. 

 All other treatments caused the same degree of damage--12 percent of the poles killed 

 by logging. Although initial stocking of poles varied by treatments, there were no 

 differences in logging damage between the large and small tractor, stem selection and 

 group selection cutting, or high and medium initial volume classes. 



3 



