12 U. S. DEPARTMENT OF AGRICULTURE BULLETIN NO. 484. 



gipsy-moth damage. A detailed consideration of the classification in 

 this light is interesting and may prove of value in combining pro- 

 tective with improvement measures. 



Class I (p. 8) is composed of 26 species which are favored food 

 of gipsy-moth larva?. Ten of these species, mountain ash, gray birch, 

 river birch, boxelder, scrub oak, service berry, dwarf sumac, staghorn 

 sumac, glaucous willow, and witch hazel, yield products of low com- 

 mercial value and should in any case be eliminated from mixed 

 woods. 



Ten of the species in this class are oaks, including the scrub oak 

 just referred to. All oaks require the best of forest soils to develop 

 well and profitably. Oaks growing on thin soils, rocky ridges, and 

 very sandy soil are usually not very vigorous and frequently suffer 

 severely from gipsy-moth attack. If oaks were removed from the 

 unfavorable sites on which they very often occur and were confined 

 to sites best adapted to their requirements, a large amount of gipsy- 

 moth food would be eliminated, a better quality of oak would be pro- 

 duced, and there would be available a considerable acreage of forest 

 land better suited to the growth of other valuable trees. 



The bur oak, chestnut oak, pin oak, post oak, and swamp white 

 oak are generally more or less rare and of restricted local occurrence 

 in the infested region. On account of their scattered distribution 

 they are not of any great commercial importance here. In consider- 

 ation of their susceptibility to moth attack and capacity for main- 

 taining infestations, they could well be spared from most stands in 

 which they occur. 



The white oak reaches the northern limit of its range in the in- 

 fested region, but still is one of the most abundant of the oaks. This 

 abundance is abnormal and is due to the sprouting capacity of the 

 species, resistance to the effect of fire, and current methods of cutting. 

 The trees grow very slowly and seem to be particularly favored by 

 both gipsy and brown-tail moths. A very large proportion of the 

 existing trees of this species could be removed to great advantage. 



The red oak, black oak, and scarlet oak do well in the infested 

 region, and it is hoped that the experiments now under way will 

 show that there may be conditions under which they may be safely 

 grown. 



The following poplars occur in Class I: Aspen, large-tooth aspen, 

 and balm of Gilead. These species all demand a large amount of. 

 light and occur only where it can be procured. As a result they 

 generally occur scattered in mixed woods, and pure where they can 

 get the necessary start. They grow rapidly, and when they occur 

 in any abundance are in good demand for excelsior and pulp manu- 

 facture. There is some question as to what extent they should be 

 encouraged in view of their susceptibility to gipsy-moth attack. 



