14 BULLETIN 299, U. S. DEPARTMENT OF AGRICULTURE. 
in the type are spruce, hemlock, and white pine, the first two espe- 
cially on moist situations suitable to white ash. In original forests 
of this type white ash rarely forms more than from 1 to 5 per cent of 
the merchantable stand, but in second-growth stands it may form 20 
per cent or more. 
Sites on which the mixed oak and chestnut type of forest is usually 
found (exposed upper slopes and ridges and southern slopes) ha^e a 
comparatively dry, hard soil often thin and very rocky. Such sites 
are not favorable to white ash, which is fastidious in regard to soil, 
does not readily develop a rugged, deep-going root system, as do 
oaks and chestnut, and requires in consequence more surface moisture. 
On this type white ash usually occurs as a subordinate, overtopped 
tree of small diameter in comparison with the oaks and chestnut, 
except for occasional well-developed individuals in depressions where 
soil and moisture conditions are more favorable. It never forms 
over 5 per cent of the stand. Ash reproduction takes place readily 
wherever the cover is slightly broken and at the same time dense 
enough to preserve good moisture conditions in the humus and soil; 
but subsequent seedling development is usually poor because con- 
ditions are adverse. The mixed oaks and chestnut type is common 
below 1,000 feet elevation in the glaciated hills of southern New 
England, southern New York, Pennsylvania, and New Jersey; farther 
south it occurs at increasing elevations, in the southern Appalachians 
up to 4,000 feet, mostly on comparatively dry southern slopes and 
ridges. It is common in southern Michigan, Ohio, Indiana, southern 
Illinois, Kentucky, and Tennessee, and in the highlands of southern 
Missouri and northwestern Arkansas. The most frequent associates 
of white ash on this type are chestnut, red, white, scarlet, black, and 
chestnut oaks, bitternut and pignut hickories, yellow poplar, red 
maple, and dogwood; other species sometimes occurring with it are 
swamp, white, pin, Spanish, black jack, and post oaks, black gum, 
black walnut, shagbark hickory, ironwood, hornbeam, elm, black 
cherry, shad bush, sugar maple, sassafras, hemlock, white, pitch, 
and shortleaf pines, scrub pine, black and yellow birch, paper birch, 
butternut, black locust, mulberry, beech, and red gum. 
The yellow poplar type occurs only on comparatively moist, fertile 
sites with good drainage, such as in the hollows of small streams, 
north slopes, and small hollows, coves and swales interspersing drier 
oak or pine types. In old growth ash forms up to 10 per cent of the 
stand, and in second growth up to 50 per cent. The yellow poplar 
type is common from southern New England and southern New York 
(below 1,000 feet elevation) to northern Florida and west to northern 
Louisiana and eastern Arkansas and Missouri. Southward it is 
found at increasing elevations until in the southern Appalachians it 
reaches 3,500 feet; but it occurs also on moist, well-drained fertile 
