214 The Ottawa Naturalist. [Mar. 



insure the timber needs^of the future. The total forest area of 

 Canada is^estimated at over 1,250,000 square miles, of which 

 about 400,000 square miles may be considered to be covered 

 with merchantable timber. 



Two of the three factors which are chiefly responsible for 

 the destruction of our forests depend for their solution upon the 

 results of biological investigation. The three chief forest destroy- 

 ing agencies are^^fire, insects and plant diseases, and all are inter- 

 dependent. Naturally the first appears to be the most important 

 on accoimt of the extremely apparent and ravaging devastation. 

 Nevertheless the destruction caused by insects and plant diseases, 

 though usually working for a long time, insidiously and unseen, 

 is enormous. It is estimated by Hopkins that for a ten-year 

 period, during which investigations were made, the average 

 amotmt of timber in the forests of the United States killed and 

 reduced in value by insects would represent a loss of $62,500,000 

 annually. It is impossible to estimate in the absence of the 

 necessary statistics the extent of the annual loss in Canada to the 

 growing forests, but on a conservative estimate the loss on the 

 annual cut of timber due to insects in Canada would be more than 

 $2,000,000. The injury to forests by fire receives the serious 

 consideration which it merits on account of its very noticeable 

 character, but insects and fungi carrying on their destruction 

 in apparent secrecy are unobserved until their depredations 

 assume a magnitude such as to render their control almost im- 

 possible. 



Forest insects are injurious in a number of ways: they may 



attack and kill the mature growing trees ; they destroy the second 



growth and thus hinder or prevent natural regeneration; they 



attack the cut timber and the finished products to a serious 



extent ; in a word, from the seed to the finished product they 



exact no inconsiderable toll of this important and valuable 



resource. There are two classes of insects injurious to forests: 



those which defoliate the trees, and the boring insects which 



attack both living trees and the cut products. Of the former class 



we have two examples in Canada to which I may briefly refer. 



The Larch Sawfly {Nematus erichsonii), which destroyed all the 



mature larch or tamarack in eastern Canada in the outbreak of 



1881-1885, is now repeating its depredations. The second is the 



Spruce Budworm (Tortrix jumijerana), which is distributed 



throughout Quebec, and in many localities has effected serious 



defohation of the spruce and balsam during the last two years. 



In British Columbia it is also attacking the Douglas Fir and has 



already shown its ability to kill the young second growth. The 



seriousness of this outbreak of the Spruce Budworm is not only 



due to the probable effect on the trees of the repeated 



