A NATIONAL PLAN FOR AMERICAN FORESTRY 729 



FOREST INSECTS AND FOREST MANAGEMENT 



Forest entomology is not only a science of protection as emphasized 

 in the foregoing discussion but one of prevention as well. It is ob- 

 viously better to prevent outbreaks of insects from becoming destruc- 

 tive than to wait until they have gained such momentum as to make 

 direct control necessary. This objective will be attained more fully 

 in the future through proper silvicultural practices applied to the 

 growing stands whereby unfavorable conditions for the development 

 of the insects are maintained or greater resistance of the stand to 

 insect attack is developed. To determine the necessary practices 

 for this form of protection close cooperation between the personnel 

 engaged in other phases of forest research and entomologists of the 

 Bureau of Entomology has been developed at six of the Forest Service 

 experiment stations and certain results have already been obtained. 



The reforestation of abandoned farm lands and other waste lands 

 in the Middle Atlantic and New England States has been materially 

 retarded through the activities of the white-pine weevil as already 

 mentioned. Northern white pine, a most desirable and fast-growing 

 tree, has been more extensively used for this purpose than any other 

 species. With the enormous increase in the acreage of susceptible 

 material, the white-pine weevil has increased to such an extent that 

 it has become a serious menace. A thorough study of the problem 

 has indicated that if these plantations are confined to the better sites 

 and the trees spaced not greater than 6 by 6 a profitable crop can be 

 obtained regardless of weevil attack. More recently it has been 

 found that, even in those stands which have been very severely 

 injured, it is possible to carry out certain reclamation practices which 

 will at least give a fair yield from stands which otherwise would be a 

 total loss. 



The production of spruce and fir pulpwood in the New England 

 region is intimately associated with the activities of the spruce bud- 

 worm. Recent investigations have shown that the mortality in vari- 

 ous stands following attack of this insect is directly correlated with 

 the vigor and the composition of the stand. In other words, if rapid 

 growth and a low percentage of fir is maintained, the forest will be 

 practically immune. 



The woods practices of a decade ago in the naval-stores industry 

 in the South resulted in extravagant losses from dry facing and 

 windthrow. The latter frequently affected such a high percentage 

 of the stand that the crop was abandoned. This windthrow was in 

 a large measure the result of the weakening of the trees by an bisect 

 boring in the heart wood of the tree. It gained entrance to the tree 

 through the faces in the turpentined timber. Investigation showed 

 that this loss was preventable through the adoption of conservative 

 practices which at the same time increased the yield of gum and 

 greatly prolonged the period of operation on a given area. 



Black locust, a fast-growing tree which has been extensively planted 

 in recent years, particularly on poorer soils, for the purpose of 

 checking erosion, suffers extensively from the attack of the locust 

 borer. In many sections of the country it has been found impossible 

 to secure satisfactory artificial stands. Often the value of the mate- 

 rial may be reduced to a point where it is practically useless except 

 for purposes of fuel. On the other hand, natural stands are rarely 



