INSECTS AND FOREST MANAGEMENT — CRAIGHEAD 387 



Forest Service and the Bureau of Entomology to obtain more specific 

 data and to test out theories by means of experimental plots. This 

 study was assigned (Clement, 1917) to Clement and Munro, who re- 

 ported on their work in Bulletin 484 of the United States Department 

 of Agriculture. They indicated certain possibilities and certain limi- 

 tations, chiefly economic, in the application of management to gypsy 

 moth control. The proposals were a little ahead of the times and no 

 general application resulted. 



A more recent study of this problem in central Massachusetts 

 through cooperative efforts of the Bureau of Entomology and Plant 

 Quarantine, the Harvard Forest, and the Northeastern Forest Experi- 

 ment Station developed more specific information. First, Baker and 

 Cline (1936) showed that no serious defoliation occurred unless more 

 than 50 percent of the stand was composed of species of group 1. 

 Continued study led to definite recommendations by Behre, Cline, and 

 Baker (1936) and indicated that there are very far-reaching possi- 

 bilities for applying the principles of forest management to the con- 

 trol of the gypsy moth in the New England States, because of the 

 favorable conditions which existed, namely, (1) the composition of 

 much of the forest with regard to the distribution of favored and 

 unfavored food plants was suitable to work with in thinning prac- 

 tices; (2) there were large areas of second-growth hardwoods, many 

 of them with understories of conifers, which needed release; (3) the 

 Federal and State agencies were then spending considerable sums on 

 less permanent methods of control, such as spraying and creosoting 

 egg masses. This money would do more permanent good if diverted 

 to forest improvement; and (4) considerable manpower was avail- 

 able (at the time of writing) through C. C. C. camps and relief 

 organizations. 



The ice is now well broken and it is likely that silvicultural meas- 

 ures will be given more and more emphasis and the present control 

 program will change from one of temporary practices, such as spray- 

 ing and creosoting, to one involving the permanent improvement of 

 forest stands. It is reasonable to believe that with such measures a 

 large part of the present infested area can be made relatively immune 

 to the gypsy moth and a considerable reduction in expenditures for 

 control can be effected. 



These writers (Behre, Cline, and Baker, 1936) showed how the cut- 

 ting practices of the past 30 years and frequent fires led to the increase 

 of secondary types which are primarily composed of species of group 

 1, and thus brought about more favorable conditions for the gypsy 

 moth. To quote : 



Thus it becomes evident that the forest types which present most favorable con- 

 ditions for gypsy moth attaclc are the direct result of a transient agriculture 

 and the destructive liunbering practices of the past. 



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