The ratios of trees of different species and different size groups
reflect, to some extent, the changes to which the area has been
subjected. Under original conditions mature trees of oak and hickory
dominated the forest. With the opening up of the forest that resulted
from cutting most of these mature trees, other kinds of trees
increased and spread. Species relatively intolerant of shading became
established. Chinquapin oak, honey locust, osage orange, cherry,
dogwood, red haw, and crab-apple, being especially intolerant of
shading, cannot grow in close competition with climax species, and
they become established only in fairly open situations. Their presence
in thick woodland, along with climax competitors, usually is an
indication that the woodland is either of recent origin or has been
much disturbed in the past, permitting invasion by them.
About 1934 when approximately half of the Reservation, including
nearly all the woodland areas, was fenced against livestock, shrubs
and young trees sprang up in great abundance, especially in more open
woodland situations, and at the edge of the forest. Sumac (_Rhus
glabra_) often dominated at first in such situations. Crab-apple, wild
plum, red haw, chinquapin oak, prickly ash, dogwood, honey locust, and
redbud also soon came into prominence. By 1954 thickets had grown up
and the intense competition had killed much of the woody vegetation.
Sumac, especially, had been almost entirely killed out by the shading.
By then, however, the adjacent fields had been protected for eight
years from grazing, and sparse sumac thickets were present on the
field sides of the fences, the average sizes of the plants
progressively declining farther from the edge of the woods. Much
mortality had occurred also in all the other species mentioned, with
only a few of the larger surviving in competition with elm, hackberry,
ash and osage orange, and with reproduction practically stopped except
near the edges of the thickets.
In 1954, after approximately 20 years of protection from livestock,
the woodland had become much denser, with a thick understory of
saplings and tall shrubs in most places. From a time soon after
protection was initiated, there was little or no reproduction (except
where the woodland originally was open) in blackjack oak, dwarf or
chinquapin oak, red haw, honey locust, and osage orange. On one south
slope, an open woods with well scattered trees of black oak, American
elm, hackberry, honey locust and osage orange, had by 1954 become so
dense that it was almost impassable except with the aid of a brush
knife to cut or break through the thickets. Saplings of honey locust
made up an important part of the understory vegetation on this slope.
Those of the smallest size group, up to 1-1/2 inches stem diameter,
were mostly dead; in a strip 900 feet long and 50 feet wide there were
29 dead saplings and ten live ones of this size group. In the next
largest size group, up to 2-1/2 inches in stem diameter, there were 17
dead and 53 live saplings, while in the size group 2-1/2 to 3-1/2
inches stem diameter, there was one dead sapling and 51 were alive.
On another south slope, which had more large and medium-sized trees
and less dense underbrush, 233 saplings six inches or less in stem
diameter, counted on a sample strip 530 feet long and 40 feet wide,
included elm 37.3%, dogwood 19.7%, hackberry 16.4%, coffee-tree 15.6%,
honey locust 11.0%, plum 10.3%, chestnut oak 5.5%, crab-apple 3.4%,
osage orange 2.1%, red haw 1.4%, hickory, redbud, mulberry and
cockspur thorn each .7%. There was substantial mortality in the
saplings of several of these species; plum 86.5%, dogwood 69.5%, elm
49.5%, locust 31.2%, chestnut oak 25.0%, coffee-tree 4.4%.
By 1954 several areas of hilltop-edge and north slope, which
presumably had been wooded originally, but which had been subjected to
heavy cutting, supported thriving stands of young hickories mostly two
to six inches in trunk diameter. Most of these saplings seemed to have
originated as stump-or root-sprouts. These numerous and closely spaced
saplings produced a dense and almost continuous leaf canopy, shading
and killing out many of the smaller trees of their own species as well
as competing elms, redbuds, dogwoods, hackberries and others.
On a north slope in the southeastern part of the Reservation, many
large stumps were found in late stages of decay, cut from 20 to 30 or
more years before. Insofar as could be determined, these old stumps
were mostly of oaks, but in 1954 the trees growing on this slope were
chiefly elms and coffee-trees less than one foot in diameter.