42 PROTECTION OF PLANTS, 1921-22 



A FEW POINTS OF INTEREST IN CONNECTION WITH FOREST 



ENTOMOLOGY 



By M. B. Dunn, Assistant Entomologist, Entomological Branch, Ottawa 



A great many attempts have been made to estimate the actual damage done 

 to the forests of Eastern Canada during the last few years by the spruce bud 

 worm. All of these, it matters not how carefulh' they may have been carried 

 out, must necessarily be but rough approximations, but they at least serve to 

 convey some idea of the terrific havoc for which this insect is responsible. 



Last year in New Brunswick, we ran a number of test strips, 30 x 100 feet. 

 These strips were located in var3'ing types and sections of the country, having 

 only this in common that they all had at least a little of the largest timber taken 

 out. All standing trees whcse appearance denoted that their death was directly 

 attributable to the bud worm were counted and the diameter of each at four and' 

 one-half feet from the ground was taken. With volume tables kindly supplied 

 by Mr. Wm. Robertson, of the Dominion Forestry Branch, the loss in merchant- 

 able cubic feet for each strip was estimated and an average made for the various 

 strips. The average proved to be 118. merchantable cubic feet for balsam 

 and 11.7 for spruce. Carrying these figures a little further, and estimating the 

 number of strips per square mile, we find the loss in the province of New Bruns- 

 wick, which has a main forest block of approximately 100 miles square, to be 

 in the neighborhood of 10,900,000,000 merchantable cubic feet for balsam and 

 1,087,000,000 for spruce. These figures seem appalling. They appeared incre- 

 dible at first, even to the men who did the work, and we went over our calcula- 

 tions several times in the hope that there was a mistake somewhere, but none- 

 could be found. 



As a further illustration of just how much lumber such a pile would be, it 

 can be estimated that if cne had sach an amount in manufactured lumber at his 

 command, he could begin to build ccsy little seven roomed houses at Halifax 

 and, leaving only twenty feet between each house, he cold build four rows of 

 such houses clear acrcss Canada to Vancouver. 



Now this less was all in the Province of New Brunswick in a comparatively 

 small area. When one remembers how many times larger is the forest area of 

 Quebec and Ontario, and also that some of it at least is virgin territory for which 

 these figures would be too small, one begins to get some vague idea of the dam- 

 age which has been done. Added to this ceitain loss there is the almost cer- 

 tain one due to forest fires which, owing to the dry condition of the timber, can- 

 now hardly be prevented from raging over a large part of this territory. 



Another interesting phase of our work is that in connection with sample 

 plots. In co-operation with the Conservation Commission and several lumber 

 companies, we have established at various points throughout the forests of East- 

 ern Canada, a total of thirty-two sample plots. We have under observation on. 

 these plots slightl}' over twelve thousand trees, mostly spruce, balsam and pine^ 



