63() JOURNAL Ol- FORESTRY 



cent of the total number of trees. This difiference is due to the fact 

 that no hardwoods were cut in 1898 while in 1915 a very heavy cut- 

 ting of hardwoods was made. Thus in the 1898 cutting the hardwood 

 type was opened very little and the conifers were all well protected, 

 while in the 1915 cutting the hardwood type was opened up excessively, 

 much more so than the other types, and so the trees left were more 

 liable to be thrown. Moreover, all the exposed situations are included 

 in the hardwood type and the shallow rooted conifers are more sus- 

 ceptible to the opening up of the stand than the deeper rooted 

 hardwoods. 



In both cuttings and on all types balsam suffered the greatest amount 

 of damage. This can be explained by the fact that balsam is the 

 shallowest rooted of all the species and most subject to decay at an 

 early age. Moreover, in the 1898 cutting old balsams which were 

 found to be rotten at the base were left standing, while in 1915 the 

 cutting of balsam was done strictly on a diameter limit. Thus the 

 189S area contained an abnormally large proportion of rotten trees 

 liable to be windthrown, while the 1915 area contained only the smaller 

 more windfirm trees. 



Of the few hardwoods damaged the greater number appear to be 

 broken rather than uprooted, but there seems to be correlation be- 

 tween age and breaking or uprooting. 



The damage to balsam was about equally divided between uprooting 

 and breaking. Breakage was more common than uprooting in the 

 case of the larger trees, probably because such a large percentage of 

 the older balsams were rotten, and uprooting was more common in the 

 case of the smaller and hence younger trees which were still sound. 



The spruce was uprooted much more often than broken and this was 

 especially evident in the 1915 cutting, so that the thinning seems to have 

 increased the damage by increasing the proportion of uprooting to 

 breaking. 



In all cases the damage was greater to the trees of large size than 

 to those of small size in proportion to the number of trees of the 

 different sizes. 



With both spruce and balsam the site appeared to have an influence 

 over the nature and the amount of the damage. As stated above 

 these species were damaged most severely on the sites in the hardwood 

 type where the exposure was greatest. On the more protected upland 

 sites, however, where the individual trees would tend to develop a 

 deeper and more spreading root system, the damage was not so great 



