1901 



AMERICAN FORESTRY ASSOCIATION. 





commoner injuries, and in that relating to 

 some important features in their ha 

 life history, and distribution, consider; 

 progress has been made within 

 years. This technical knowlei the 



insects, of their habits, and the character 



gation of the spruce-destroying beetle of 

 the northeast demonstrated the fact that 

 this great destroyer of the spruce attacks 

 only the larger and matured trees over 12 

 inches in diameter, thus suggesting the 

 importance of harvesting the matured 

 timber and leaving the younger 

 growth for future supply. It was v;v\v, 

 also found that the insect is single- 

 brooded in the Maine woods, and 

 that it can be attracted to hack- 

 girdled trap trees. Thus if a large 

 number of trees are girdled in an 

 area marked for cutting- the fol- 

 lowing winter, and they are near 

 an area of matured timber that 

 it is desired to protect for subse- 

 quent cutting, the trap trees may 

 be cut during the ordinary log- 

 ging operations. In this way the 

 trees with their cargoes of insects 

 may be removed during the spring 

 log drives, before the broods 

 emerge and thus lessening danger 

 to the other timber. Therefore, 

 with no additional expense beyond 

 that of girdling, vast numbers of 

 the insects will be effectually de- 

 stroyed and the remaining timber 

 over considerable areas protected 

 from their ravages. 



There are many other results 

 obtained in recent investigations, 

 which suggest methods of pre- 

 venting losses from the depre- 

 dations of insects on forest trees 

 and forest products. These, even 

 under American conditions, are 

 capable of practical application, 

 in some cases involving simply an 

 inexpensive change in time of cut- 

 ting and methods of handling the product. of their work will be of prime importance 



Other methods suggested from these in subsequent investigations to determine 

 studies require, for their successful appli- practical methods of preventing 

 cation, the adoption of scientific forest 

 management. In the case of the chestnut 

 timber worm this would require the har- 



CHARACTER OF INJURIES TO OAK BV THE OAK 

 CARPENTER WORM. 



vesting of all matured timber, the destruc- 

 tion by fire of all defective trees, and the 

 prevention of wounds on the young and 

 thrifty timber. 



In the accumulation of data relating to 

 the kinds of insects to blame for the 



However, it will require a considerably 

 greater expenditure of time and monej 

 than has yet been available, to demonstrate 



the practical value suggested b) the knew 1- 

 edge already obtained. 



Experiments in girdling and cutting 

 timber at different times in the year, 

 determine the relations of time of cutting 

 to exemption from attack 1>_\ insects, and 



