CONTROL OP GIPSY MOTH BY POREST MANAGEMENT. 13 



Basswood occurs very much scattered in the infested region. It 

 grows to advantage only on the best sites and should be eliminated 

 from all others. 



Beech occurs most abundantly in the northern portion of the 

 region. It grows slowly and is liable to become defective before ma- 

 turity. It is perhaps the least liable to damage of any Class I trees. 



Paper birch demands a great deal of light and is not abundant in 

 mixed stands. Where it occurs in abundance it is in great demand 

 for spool and novelty wood. Scattered specimens may be replaced 

 with species which are less liable to gipsy-moth attack. 



Tamarack is nowhere abundant in the infested region. It is a 

 tree which can well be cut out when found outside of pure stands. 

 It is the only conifer which is eaten by the youngest gipsy-moth 

 larvae. 



Class II (p. 9) is composed of eight species of trees on which 

 gipsy-moth caterpillars in their earliest stages do not feed, but upon 

 which they do feed in their later stages. Young caterpillars must 

 have food, and if this is not available they can not attain the point 

 in their development where they can feed on the trees of this class. 

 Hence if stands of these trees have in their vicinity no plants upon 

 which the young caterpillars can feed, the stands are practically im- 

 mune from attack. Trees of this class can therefore be safely grown 

 in pure stands, in mixture, where conditions permit, with one 

 another, or in mixture with Class IV trees. 



Stands composed largely of one or more of the species of this class 

 can be made immune from gipsy-moth attack by removing the plants 

 which may provide young larvae with food. Since most of the spe- 

 cies which are susceptible to gipsy-moth attack are deciduous, pro- 

 vision in this case will have to be made for the suppression of the 

 sprouts which follow cutting. 



Trees of this class may be substituted frequently for removed trees 

 of species susceptible to moth attack. The white pine is particularly 

 important in this respect, owing to its commercial value, rapidity of 

 growth, and adaptability to a variety of sites. The red pine, while 

 somewhat slower growing and of slightly less value, is also a valu- 

 able tree and deserves particular consideration owing to its immunity 

 from the white-pine blister rust. 



Chestnut is the only deciduous tree of this class. It grows well 

 and yields a valuable product, but unfortunately is subject to attacks 

 of the chestnut blight. In the light of existing conditions the propa- 

 gation of this species can not be advocated. 



Class III (p. 9) is composed of 20 species which are not par- 

 ticularly favored, but upon which a small proportion of gipsy-moth 

 larvae may develop. Stands composed of any trees of this class and 

 containing none of the trees of Class I would maintain slight infesta- 

 tions and would rarely, if ever, be defoliated. 



