IMPORTANT NORTH AMERICAN FOREST INSECTS d 



INSECTS AFFECTING FOREST MANAGEMENT 



Cooperation with the Forest Service experiment stations forms 

 another important line of activities. At present entomologists are 

 stationed at, or are in close touch with, five of these experiment 

 stations, namely, the Lake States Forest Experiment Station, St. 

 ^ Paul, Minn., the Northeastern Forest Experiment Station, Amherst, 

 |) Mass., the Appalachian Forest Experiment Station, Asheville, N. C, 

 the California Forest Experiment Station, Berkeley, Calif., and the 

 North Pacific Forest Experiment Station at Portland, Oreg. It 

 is planned for the future to have entomologists assigned to each 

 station. 



The investigations carried on under this form of cooperation 

 have to do with the insect problems involved in the management 

 of the more important forest types of the regions. Through studies 

 of the major forest insect pests a better understanding of the con- 

 ditions favoring or retarding serious insect damage is gained, and 

 this knowledge is made available to foresters so that it can be ap- 

 plied in developing sound practices in timber culture. Some species 

 of trees and some types of forests are little affected by insects, but 

 in others insects may be the limiting factor in successful timber 

 production. As better cultural practices for growing timber are 

 attempted, the complex relations existing in the forests must be 

 more fully understood to avoid fatal mistakes. Insects constitute 

 one of the most important of the biotic factors. Although greatest 

 recognition is given to their role as destroyers of green standing 

 timber, other important activities that bring about changes in the 

 composition of the forest can not be disregarded. Insects often 

 increase the percentage of undesirable species of trees, inhibit the 

 reproduction of certain desirable species, affect the rate of growth, 

 and thus lengthen the rotation period and augment the ill effects 

 of fire. Investigations dealing with these varied problems are under 

 way. 



Some other problems of a more specific character are under in- 

 vestigation, such as the entomological aspects of slash disposal (72), 

 the interrelation of insects and forest fires (78, 79), turpentining 

 practices and insect damage, insects affecting nursery practices, and 

 insect injury to the seed of forest trees. 



INSECTS INJURIOUS TO SHADE TREES AND ORNAMENTAL SHRUBS 



Little in the way of investigation of insects affecting shade and 

 ornamental trees and hardy shrubs is done at the present time, and 

 most of the effort in this work is expended in service. There is 

 a great and increasing demand from municipal authorities, estate 

 owners and managers, small property owners, tree surgeons, and 

 nurserymen for advice on methods of handling their entomological 

 problems. The division of forest insects attempts to meet this 

 demand by correspondence, publications, and occasional surveys and 

 studies. Whenever possible, observations are made on important 

 species and, where practical, experiments in methods of control and 

 improvements in such methods are conducted. 



