44 Forest Club Annual 



ing power should exist between the younger and older needles 

 of coniferous trees seems quite reasonable. 



The needles which were only partly killed by the chinook 

 apparently held their own throughout the season of 1909, but 

 by September 24 those that had been killed back more than 

 half their length were drying up and seemed to be about 

 to drop. Of course the oldest of these had already persisted 

 as long as they normally would, and would have fallen, injury 

 or no injury, but others would have stayed on for two or three 

 years longer, had it not been for the winter injury. 



In eases of severe injury all the needles on the trees were 

 killed. Some of these defoliated trees were killed outright. 

 A very few were partially killed, but part of the branches 

 continued to grow during 1909. In many such cases the 

 buds on living branches appeared to be so injured that they 

 were unable to develop properly during 1909; instead of 

 normal increase in length of the twigs with formation of many 

 new needles of normal size, there was very slight growth in 

 length of the twig, and a few needles, twice the normal length 

 were formed. That is, the prevention of length growth of the 

 twigs, due to partial failure of the bud, resulted in increased 

 needle growth just back of the injury. These abnormal needles 

 can therefore be considered analogous to the water-sprouts or 

 "suckers" just back of the points of pruning, which are fa- 

 miliar results of cutting back broad-leaved trees. A great 

 many of the trees which were partly killed and which made 

 weak or abnormal growth during 1909 were found dying in 

 September; this was accompanied by the presence of ia brown 

 discoloration or of beetle larvae in the bark. Whether all of 

 these would have died as a direct result pf the winter injury, 

 or whether the immediate causes of death were bark beetles or 

 facultative parasitic fungi encouraged by the weakened con- 

 dition of the tree, was not determined. Cultures made from 

 the patchy discolorations in the bark of dying trees not in- 

 jured by insects produced no fungus likely to be parasitic. 



Practically all of the defoliated trees which were not killed 

 outright suffered no real harm. Growth was resumed in the 

 normal manner in the spring of 1909. In the older trees growth 

 is so slow that whether or not the growth in 1909 was ma- 

 terially decreased by the defoliation was not determined. On 



