THE GENUS DENDROCTONUS. 35 
the beneficial insects will escape. Or, if it is not necessary to burn 
the bark, practically all will escape, and thus assist in destroying the 
broods left in the tops of trees and those in scattering trees. It is 
always important, therefore, to determine whether or not the natural 
enemies are present in sufficient numbers to make it worth while to 
adopt special precautions for their protection. 
Wherever woodpeckers are common in a forest they may aid greatly 
in destroying the broods of ' barkbeetles in the scattering clumps and 
isolated trees, especially if the beneficial insects are scarce. If, on 
the other hand, the beneficial insects are common, the birds may 
feed on them and do as much harm as good. The protection of the 
birds, however, should be maintained, because even if they are harm- 
ful at times they evidently more than compensate for it in the general 
service they render to the forest. 
IMPORTANCE OF SYSTEMATIC FORESTRY. 
After all, success in the control of these beetles and of forest insects 
in general depends more upon good forest management, perhaps, 
than upon anything else relating to the practical phases of the 
problem, for without some organized system of management very 
little can be accomplished toward the successful utilization of avail- 
able information or methods of control. It is equally true, however, 
that unless the available knowledge relating to the insects and the 
principles of their control is understood and properly utilized in 
forest management and lumbering operations, nothing will be ac- 
complished, and the depredations and great losses of valuable timber 
will continue. 
SOME RESULTS OF EFFORTS TO CONTROL BEETLE DEPREDA- 
TIONS. 
It is only within recent years that any detailed work has been done 
on the forest insects of North America, and the possibility of con- 
trolling their depredations is not generally recognized, even among 
foresters. Organized efforts and definite results were not, therefore, 
to be expected, yet we have a few examples which may serve as 
demonstrations of what can be done. In 1900 the eastern spruce 
beetle was killing a large amount of mature spruce in northwestern 
Maine. This was investigated and the concentration of the logging 
operations in the infested sections was recommended. This recom- 
mendation was adopted, and with little or no additional expense 
sufficient numbers of the infested trees were cut the first winter, and 
the logs floated out in the spring, to check the ravages of the beetles, 
and, so far as can be learned, up to the present time very little timber 
has since died in that section as the result of insect attack. 
