CONTROL OF GIPSY MOTH BY FOREST MANAGEMENT. 23 
species and its ability to grow in soil too poor for other oaks have 
enabled it to maintain itself and to increase the area occupied in spite 
of cutting and fires which have reduced the proportion of the pine 
originally present. These characteristics make the species, although 
seldom fit even for saleable firewood, a controlling factor in manage- 
~ ment when it is found in sufficient numbers. 
BLACK, RED, SCARLET, AND WHITE OAKS. 
These oaks should be confined to soils best adapted to their require- 
ments. Such soils are often suitable for agricultural crops. Sites 
too rough for agriculture are often excellent for hardwoods other 
than oak or for white pine. To one knowing nothing about it, it 
sounds very simple to cut the oaks and plant pine, but the power of 
abundant reproduction by sprouts, common to these species, makes 
such a conversion a difficult and expensive proceeding, and owing to 
this their presence in a stand in sufficient numbers makes them con- 
trolling factors in management. | 
CHESTNUT. 
Chestnut has an intolerance of shade which prevents the seedlings 
from coming up in any dense shade, even that of sprouts of the same 
species. The supply of seed 1s usually scanty, owing to the general 
practice of gathering the nuts. These facts, and its power of abund- 
ant reproduction by sprouts and their very rapid growth, all unite to 
make sprout growth the usual form in which the tree is found in this 
region. 
It does not need a rich soil, but to make good growth requires depth 
and a soil whose physical structure insures good drainage. It will 
succeed on soils too dry for beech or maple. There are large areas of 
glacial drift throughout the white-pine region well adapted to chest- 
nut. It is never found in stands 100 per cent pure, but mixed hard- 
wood stands with 60 to 80 per cent of chestnut are not uncommon. 
When so numerous on suitable sites its sprouting capacity and rapid 
growth make this species a controlling factor in management.’ 
HEMLOCK. 
That portion of New England now infested with the gipsy moth is 
not especially adapted to hemlock, which reaches its largest size in 
the coves of the mountains of West Virginia, North Carolina, and 
Tennessee. In the white-pine region pure hemlock stands are rare, 
and the proportion of the area now bearing any hemlock is small. 
Tt is confined, as a rule, to moist ravines and cool slopes, where it 
should be permanently retained, for its adaptability to such sites 
makes it there a controlling factor. For the protection of water- 
1 The susceptibility of chestnut to the chestnut bark disease is another factor that must 
be considered in this connection. See comment on page 40. 
