NOTES AND COMMENTS 



Injury to Yellow Pine Timber by Steam Logging 



Mr. O. F. Ericson reports the results of a recent study of a cut- 

 over area on the Crater National Forest, in southern Oregon, to deter- 

 mine the effect of steam logging on the remaining stand of yellow pine 

 timber. A 100 per cent cruise was made on a 16-acre plot containing 

 243 yellow pine trees, which represented as nearly as possible the con- 

 dition of uphill yarding on the sale area. The slopes were more or 

 less broken and rocky and were very characteristic of the tract where 

 donkey logging was being carried on. Figures were obtained only for 

 yellow pine, which is the most favored and predominant species in the 

 region, although there are considerable quantities of Douglas fir and 

 white fir to which the damage is usually greater than to the yellow 

 pine. The study showed the number of trees injured, according to 

 the per cent of the trunk girdled, to be as follows : 



Number of Per cent 



Per cent trees of total stand 



10 22 " 9.1 



20 4 1.6 



30 6 2.5 



50 and over 4 1.6 



Total 36 14.8 



It was noted that the greatest damage was done by the main line 

 and logs rubbing against the trees as the logs are pulled in, which ac- 

 counts for the large percentage of trees injured to the extent of only 10 

 per cent and less. The haulback line was usually well guided by blocks, 

 and very little damage was done by this source. . Most of the trees were 

 only injured enough to expose the cambium to a very slight extent. It 

 is believed that these trees will not be retarded in their growth, as the 

 scars are quickly covered over with pitch, thereby preventing the 

 entrance of fungi and insects. The greatest damage to the individual 

 trees was caused by the straps thrown around the tree on which the 

 blocks are placed. This injury, where the straps wear through the 

 bark, usually exposes the cambium layer around the entire tree. How- 

 ever, this can be prevented by instructing the hooktenders to use the 

 inferior species or high stumps for this purpose, thus reducing this 



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