42 



METHODS OF REDUCIN(4 THE NUMBER OF BEETLES. 



The fact that a large number of beetles must attack a living, healthy 

 tree in order to inflict injnry sufficient to canse its death, and thus 

 ofi'er the best conditions for its futui-e mnltiplication and spread, is 

 of special importance since, if their numbers can be reduced below 

 that necessary to kill the trees, their depi'edations on the living tim- 

 ber must end. The insect can then onlysni-vive in weakened, dying, 

 or felled trees. It would thus i-emain harmless until some special l.\" 

 favorabh' condition would enable it to accumulate, or migrate from a 

 distance, in sufficient nnml)ers to again snccessfnlly invade the living- 

 timber. 



The facts which have been determined regarding the habits and life 

 history of the beetle snggest three methods by which their numbers 

 can be reduced : 



I. To regulate the wintei" logging opeivitions so that as many of the 

 dying and infested trees as possible can be cut and the logs therefrom 

 placed in riv<M-s, ponds, or lakes between October 1 and June 1. 



I)ift"ei-ent stages of the Dendi'oct-onus I'cmain in the bark during the 

 summer, cease active work about the middle of October, remain in the 

 bark over winter and until about the middle of June befoi-e the adults 

 emerge. The part of the trees that is infested is that which is util- 

 ized for logs. 'JMiei-efore, if the trees are cut any time after tlu\y 

 become thoroughly infested, and the logs are hauled to the landings 

 in the winter, i)laced in the water and driven out of the woods in the 

 spring, vast numbers of the insects will be either drowned or so far 

 removed from the larger standing spruce that they can do no harm. 

 There are eight months in which to do the work; so if the regular 

 logging operations are (as suggested by Mr. Cary) turned in tin? direc- 

 tion of the worst infested areas there will be little additional expense 

 in the practical ap[)lication of this method. 



II. To regulate the summer operations so that as manj^ of the 

 infested trees as possible can be cut while the bark will peel, by the 

 i^emoval of which from the logs and stumps of such trees most of the 

 insects will be destroyed. 



It is the practice in some sections to cut the spruce at a time when 

 the bark can be readily removed, thus facilitating transpoi-tation to 

 the mills; therefore, if the cutting can be tui'ued in the direction of 

 the dying and infested spruce, there will be little or no additional 

 expense in cutting and removing the bark from such trees, and thus 

 all of the eggs and young stages of the beetle will be elfec^tually 

 destroyed by the exi^osure and the drying of the bark. ^Vnother 

 advantage of this method, it would seem, lies in the fact that trees 

 l)eeled eithei- in the winter or summer can, if necessary, be left in the 

 woods for several years, probably without serious detriment. The 

 preservation of such peeled logs could be facilitated b}^ placing some 

 of tlie removed bark along the tops of the logs to prevent undue 



