The University of Kansas Natural History Reservation, in the
northeastern corner of Douglas County, Kansas, is situated in an area
that originally supported two types of climax vegetation, tall grass
prairie, and hardwood forest. These associations were distinct and
sharply defined. The present distribution of the different species of
trees on the area, supplemented by the data from snails, indicates the
approximate distribution of the two original climaxes. The principal
climax trees of the original forest were mossy-cup oak (mainly in
bottomlands), black walnut, shagbark hickory, hackberry, red oak,
black oak (mainly on hillsides and hilltop edges), chestnut oak
(mainly on rocky upper slopes). Subclimax trees characteristic of
marginal situations include: American elm, red elm, white ash, honey
locust, osage orange, coffee-tree, red haw, dogwood, redbud, cherry,
wild plum and crab-apple. Others characteristic of hydroseral
situations include sycamore, willow (of four species), and cottonwood.
In the Kansas River flood plain and small tributary valleys, rich
mesophytic forest of predominantly oak-hickory type was present. In
somewhat stunted form, and with partial replacement of its species by
those of more xeric habit, it extended up onto hillsides sloping
north, east or west, and onto the adjacent hilltop edges. Slopes
having poor shallow soil and exposures mainly to the south supported
chiefly tall grass prairie, but also had compact clumps of blackjack
oak and post oak, usually more or less isolated from other parts of
the woodland. Hilltops were mostly treeless (except near their edges)
and supported a tall-grass prairie vegetation. Shrubs and various
kinds of small trees must have been a much less conspicuous part of
the woodland flora than they are at present, and occurred in small
ravines where shelter was inadequate for the larger forest trees, and
also along the extensive line of contact between forest and open land.
One of the earliest changes was the destruction of the bottomland
forest. With the rapid settlement of the region in the sixties and
seventies, lumber was in demand and the supply was limited. The
cleared land was productive as pasture. Heavy grazing combined with
drought, gradually altered the original tall grass prairie; the
bluestems and other perennial grasses were replaced by the introduced
blue grass and by various weedy forbs. Prolonged protection from fire
permitted encroachment of trees and shrubs into situations where they
had not grown previously. Heavy grazing however, tended to hold in
check the spread of the woody vegetation.
When the bottomlands had been cut over, lumbering operations were
extended onto those hillsides where the better stands of trees were
located. The cutting of large, mature oaks, walnuts, and hickories
opened up the woodland and permitted large scale encroachment by
subclimax species. American elm, especially, sprang up in thickets.
Ash, honey locust, cherry, red haw, crab-apple, dogwood, and the
introduced osage orange, thrived and spread in the situations to which
they were especially adapted. These species largely replaced the
original climax. Some of the trees cut, the oaks, sycamores, and
hickories, usually produced fast-growing stump sprouts and competed
vigorously with the invaders. At each successive cutting, however, the
climax species lost ground. American elm, being tremendously prolific
of seed, and only a little less tolerant of shading than its climax
competitors, soon became the dominant tree of the woodlands.