Invasion of Fields
In 1948 when the extensive open parts of the Reservation were grazed and cultivated, small trees were inconspicuous and few. Mature trees, with trunk diameters of 9 inches to more than two feet, were distributed over the pastured areas, however, with groves of American elm, honey locust, and walnut near the edges of the woods, and occasional scattered trees of these species and of osage orange, coffee-tree, red haw, hackberry, and ash.
Table 2.—Percentages of Different Kinds of Small Trees (Six Inches to a Foot in Trunk Diameter) on Different Slope Exposures.
North slopesHilltopsWest slopesSouth slopesElm29.629.934.657.9Chestnut oak29.617.515.5.4Hickory11.125.428.4.8Walnut5.6.77.45.3Hackberry13.01.03.726.4Black oak1.916.3Red oak1.96.8Locust3.33.0Osage orange2.01.5Coffee-tree1.9.71.1Cherry.4Red haw2.4Mulberry.7Redbud9.33.7.8Boxelder2.6Total trees in sample54295162266
In 1949 soon after the discontinuance of grazing and cultivation, a large crop of tree seedlings became established. Each year thereafter the numbers were augmented by new crops of seedlings, but conditions rapidly became less favorable for their establishment, as the ground cover of herbaceous vegetation became thicker. The numbers and kinds of young trees that became established differed markedly in different situations. The seedlings present in large numbers were those of elm, honey locust, boxelder, dogwood, walnut, osage orange and crab-apple. There was none of the climax species—oaks or hickories—in the sample.
Table 3.—Numbers of Young Trees Per Acre in Fields of the Reservation, June, 1952.
Bottomland pastureHilltop pastureBottomland fallow fieldHilltop fallow fieldPrairieNo. of 1⁄100 acre plots sampled25080708050Honey locust83.058.85.6Elm80.072.5138.8230.0150.0Boxelder1.61.222.9200.0Dogwood18.818.811.451.244.0Walnut2.050.07.15Osage orange16.048.7Crab-apple7.293.81.2Red haw5.217.52.82.54.0Coffee-tree4.81.2Hackberry2.82.0Cottonwood.2Ash8.83.7Plum.8Peach.2Cockspur thorn.821.3Sycamore.41.2Cherry1.22.0Total number counted236393279296402
Table 3shows the numbers of young trees counted in a total of 530 plots of 1⁄100 acre each, in June, 1952. The trees counted included all those approximately one foot high or larger. A few were up to 12 feet tall, but most were between one foot and five feet in height. Not included were the many smaller seedlings, which were mostly concealed beneath the dense layer of low herbaceous vegetation.
Of young trees there were most on the bluestem prairie area, lesson the former pastures and least on the fallow fields. In both the pasture areas and the fallow fields, the bottomlands had fewer trees than the hilltops—60 per cent and 94.3 per cent, respectively. In every instance the abundance of young trees seemed to be inversely proportional to the amount of competing herbaceous vegetation. The bottomland fallow fields, which had the fewest tree seedlings, were dominated by a rank growth of giant ragweed and sunflower, often as much as ten feet tall, effectively shutting most of the light from the tree seedlings. By 1954, however, the sunflower was nearly eliminated, and the giant ragweed, though still abundant, was much stunted.
The bluestem prairie on an area of hilltop and upper slope had not been burned over or otherwise disturbed for some years prior to 1948, and probably trees began to invade this area years before they invaded the fallow fields and pastures accounting, in part, for their greater abundance in 1952. Approximately half of the young trees on this prairie area were boxelders, which were relatively scarce on the other four areas. Elm was either first or second in abundance on each area. On both types of pasture areas honey locusts were appearing in abundance and osage orange seedlings were present in somewhat smaller numbers. However, these two kinds of trees were almost entirely absent from the other areas sampled, except that a few locusts were recorded on a hilltop fallow field. In 1948 honey locust seeds were noticed in great abundance in the droppings of cattle; their dispersal in this manner probably is in large part responsible for the abundance of young honey locusts throughout the former pastures. Osage orange may have been distributed in the same manner. Seedlings of dogwood were moderately numerous on each one of the areas sampled, and those of red haw were somewhat less abundant on each area. Crab-apple was the most abundant species invading the hilltop pastures but was scarce or absent in the other situations. The remaining species of trees, including coffee-tree, hackberry, cottonwood, ash, plum, peach, cherry, cockspur thorn, sycamore, and redbud, each made up only a small percentage of the tree crop in the situations where they occurred.
In late July and early August, 1954, counts of young trees were made again on the upland pasture area, with a total of 200 1⁄100-acre plot samples. This sample was taken at the end of one of the longest and most severe droughts in the history of the area. Both 1952 and 1953 had drought summers, and up to the end of July thesummer of 1954 was exceptionally dry also. The conditions of the young trees at this time, in the relatively dry and shallow hilltop soil, was especially significant. As might have been anticipated, in this 1954 count, young trees were more numerous than they had been on any of the areas sampled in 1952. However, the data for 1952 and 1954 are not entirely comparable, because in 1952 none of the plots sampled was nearer than 50 feet to the edge of the woods, whereas in 1954, the sample was arranged to be representative of the entire field, including the parts adjacent to the woods. The numbers per acre of each kind of tree, and the percentages that were dead or dying, were as follows: crab-apple 167 (33.5 per cent dead); locust 98 (3 per cent dead); elm 69.5 (2.9 per cent dead); osage orange 63.5 (none dead); walnut 36.5 (4.1 per cent dead); red haw 25.5 (none dead); ash 19.5 (none dead); cockspur thorn 17 (17.6 per cent dead); wild plum 14 (3.6 per cent dead); dogwood 9.5 (none dead); prickly ash 2 (25 per cent dead); black oak 1.5 (none dead); boxelder .5 (none dead). Thus, of the species that were prominent invaders of the field, only crab-apple showed heavy mortality. In many instances the mortality in crab-apple was due wholly or in part to attack by cottontails (Sylvilagus floridanus), which had completely girdled many of the stems. In general, mortality in the young trees was light in this grassland area compared with the mortality in any part of the woodland.
Competition and Mortality
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 inmore 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 1½ 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 2½ inches in stem diameter, there were 17 dead and 53 live saplings, while in the size group 2½ to 3½ 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.
Effects of Livestock
Livestock importantly affected the trend of succession. The tendency of grazing animals to hold back the forest by stripping the foliage from young trees and killing them is selective, however; the several kinds of trees differ in their tolerance to browsing and in their palatability to animals. The kind of animal and the season and intensity of use also have important bearing on the ultimate effect. Several kinds of shrubs and small trees seem to be especially susceptible to damage by browsing; chinquapin oak, crab-apple, plum, hazel, dogwood, prickly ash, and paw paw were found to be either absent entirely from the parts of the woodland that were heavily used by stock, or much scarcer than they were on adjacent unbrowsed areas. Some woody plants that are even more susceptible may have been completely eliminated by browsing.
In the thirties when most of the woodland area was fenced off and protected from grazing, three wooded hillside areas of a few acres each, were maintained as connecting strips between the pastures of the hilltops and those of the bottomlands. These areas were utilized only at certain seasons, but by 1948 the effect of trampling and heavy browsing by livestock was conspicuous. Herbaceous ground vegetation was almost lacking and low woody vegetation was also scarce, in contrast to the parts of the woodland that were adjacent but separated by fences that excluded livestock. The contrast was perhaps heightened along the fences because the animals tended to follow along the fence lines and their effects were concentrated there.
Table 4.—Numbers of Young Trees of Various Kinds and Sizes in 1954 on a .919-acre Area Consisting of Six Hillside Strips Each 20 Feet Wide. Each Strip Was Equally Divided by a Fence Line, Excluding Livestock from One Side During the Period 1934 (Approximately) to 1948.
Less than ½-inchstem diameter½-inch to 4-inchstem diameter5-inch to 12-inchstem diameterTotalNumberPercent-age inbrowsedhalfTotalNumberPercent-age inbrowsedhalfTotalNumberPercent-age inbrowsedhalfDogwood55652.1105816.4Redbud4042.51025.9Elm3076.718927.69947.5Hackberry13139.720613.1520.0Plum2677.03522.81100.0Crab-apple11100.04637.0Red haw1100.03348.5975.8Walnut728.63243.72661.5Honey locust2100.02015.01127.3Osage orange1100.0757.1250.0Shagbark hickory3100.04273.84440.9Chestnut oak2630.82458.2Chinquapin oak12100.01100.0Coffee-tree1118.1812.5Ailanthus633.36526.13100.0Black oak540.0716.6American ash21100.0333.3Paw paw126127.8
In 1954 ten-foot wide strips were sampled on both sides of the fences. For both browsed and unbrowsed samples, the strips had a total length of 4000 feet, each representing an area of .919 acres.Table 4contrasts the number of young trees per acre on the browsed and unbrowsed areas, grouped in several size classes. In general the saplings up to one-fourth inch in diameter were those that had become established in the five growing seasons since browsing was discontinued and both areas were protected. For this size group the numbers were approximately equal, being slightly higher on the browsed strips. However, in the size group of ½ inch to 4 inches in stem diameter, the trees were nearly three times as abundant on the unbrowsed areas, and most trees within this size range must have become established within the time of differing treatments. The disparity in numbers was great for hackberry, redbud, elm and dogwood which made up the bulk of the saplings. In the size range 5 to 12 inches most trees antedated the fence, and the unbrowsed portion had only a few more than the portion that had been browsed.
On the formerly browsed areas clumps of gooseberry bushes were conspicuous and were computed to cover 3.81 per cent of the area sampled, versus 2.87 per cent on the unbrowsed area. These thorny bushes seem to be resistant to browsing, and elsewhere have been noted in abundance in woodlands heavily used by livestock. The elimination of competing undergrowth by browsers may be a factor favoring development of gooseberry clumps. The trend was just the opposite for fragrant sumac, which was computed to cover 1.94 per cent of the browsed sample versus 3.23 per cent of the unbrowsed sample. Greenbrier (Smilax tamnoides hispida) was most abundant on the unbrowsed strips, with seven large clumps, and 56 smaller clumps (10 stems or fewer) as contrasted with five large clumps and 32 smaller clumps on the browsed strips. There were 32 grapevines (Vitis vulpina) on the unbrowsed strips and only seven on those that were browsed.
Animal Associates
The invertebrates of the University of Kansas Natural History Reservation have not been intensively studied. Most of the species of vertebrates are characteristic of the deciduous forest of the eastern United States, or of the edge of woodland; relatively few kinds are characteristic of prairies.
Of birds, for example, some 23 species characteristic of the eastern deciduous forests have been found nesting on the Reservation, as have 14 additional species that are mainly eastern in their distribution but are most characteristic of forest-edge thickets, clearings, or marshy places. The ruffed grouse (Bonasa umbellus) and wild turkey (Meleagris gallopavo) are not present on the area, although they may have occurred there earlier. Other forest birds which occur in the general area, and which have been recorded from time to time on the Reservation, although they seem not to nest there, are: chuck-will's-widow (Caprimulgus carolinensis), scarlet tanager (Piranga olivacea), Acadian flycatcher (Empidonax virescens), veery (Hylocichla fuscescens), parula warbler (Parula americana), oven-bird (Seiurus aurocapillus), and orchard oriole (Icterus spurius). For each of these, habitat conditions on the Reservation seem to be deficient in some respect. On the other hand, the only typical prairie bird that breeds on the Reservation is the dickcissel (Spiza americana). Others, including the Swainson hawk (Buteo swainsoni), greater prairie chicken (Tympanuchus cupido), upland plover (Bartramia longicauda), western kingbird(Tyrannus verticalis) and loggerhead shrike (Lanius ludovicianus), occur in the general area, and may even cross the Reservation at times, but they do not become established.
In the mammalian fauna, species typical of the deciduous forests include the opossum (Didelphis marsupialis), short-tailed shrew (Blarina brevicauda), eastern mole (Scalopus aquaticus), eastern gray squirrel (Sciurus carolinensis), and pine vole (Microtus pinetorum), but the eastern chipmunk (Tamias striatus) and southern flying squirrel (Glaucomys volans) are lacking. Also, the present fauna lacks large mammals that may have been present under original conditions: the white-tailed deer (Odocoileus virginianus), recorded on the area from time to time but not permanently established there, the wapiti (Cervus americanus), black bear (Ursus americanus), and bobcat (Lynx rufus). Other species on the area, that are characteristic of the deciduous woodlands, but that occur also far west into prairie regions, include the little short-tailed shrew (Cryptotis parva), raccoon (Procyon lotor), fox squirrel (Sciurus niger), white-footed mouse (Peromyscus leucopus), eastern woodrat (Neotoma floridana) and eastern cottontail. On the area, the only mammals that are sharply confined to grasslands, elsewhere as well as on the Reservation, are the plains pocket gopher (Geomys bursarius) and plains harvest mouse (Reithrodontomys montanus), both of which are rare on the area, and the hispid cotton rat (Sigmodon hispidus). The following species are typical of the plains, but they range eastward into the region of deciduous forests: western harvest mouse (Reithrodontomys megalotis), deer mouse (Peromyscus maniculatus), coyote (Canis latrans), and spotted skunk (Spilogale putorius). The following mammals, typical of grassland, are absent: black-tailed jack rabbit (Lepus californicus), black-tailed prairie dog (Cynomys ludovicianus), 13-lined ground squirrel (Spermophilus tridecemlineatus), Franklin's ground squirrel (Spermophilus franklinii), southern lemming-mouse (Synaptomys cooperi), and of course, the buffalo (Bison bison), and the prong-horned antelope (Antilocapra americana) long extinct in this part of their range.
Of amphibians and reptiles also, the majority are typical forest species, including: the American toad (Bufo terrestris), common tree frog (Hyla versicolor), brown skink (Lygosoma laterale), common five-lined skink (Eumeces fasciatus), worm snake (Carphophis amoenus), pilot black snake (Elaphe obsoleta), DeKay snake (Storeria dekayi), western ground snake (Haldea valeriae), copperhead (Agkistrodon contortrix), and timber rattlesnake (Crotalushorridus). Other typical forest species missing from the area include the spring peeper (Hyla crucifer), Carolina box turtle (Terrapene carolina), coal skink (Eumeces anthracinus), and red-bellied snake (Storeria occipitomaculata). Of typical prairie species only the Kansas ant-eating frog (Gastrophryne olivacea) and the ornate box turtle (Terrapene ornata) are common, and, curiously, each seems to prefer a forest habitat on this area, in the absence of their closely related eastern representatives, the eastern ant-eating frog (G. carolinensis) and the Carolina box turtle, respectively, which usually live in forests. The plains spadefoot (Spea bombifrons), garden toad (Bufo woodhousii), Great Plains skink (Eumeces obsoletus), prairie skink (Eumeces septentrionalis), slender tantilla (Tantilla gracilis), prairie rat snake (Elaphe guttata), bull snake (Pituophis catenifer), and blotched king snake (Lampropeltis calligaster) are all scarce on the area. The plains toad (Bufo cognatus), collared lizard (Crotaphytus collaris), except for an introduced colony, plains garter snake (Thamnophis radix), lined snake (Tropidoclonion lineatum), and massassauga (Sistrurus catenatus) seem not to occur on the area at all.
Annotated List of Species
Juniperus virginiana.—Red cedar, the only native gymnosperm of northeastern Kansas, occurs in nearly all woodlands of the region, although individual trees are widely scattered. It has increased remarkably in the past few years. No mature cedar trees grow anywhere on the Reservation, but young trees, probably several dozen in all, are widely scattered in a variety of situations on the area. Probably in every instance the seeds have reached the area in droppings of birds. Approximately 15 miles south and a little east of the Reservation is a stand of cedars some of which are 100 to 300 years old. Near the southwest corner of the section, at the site of a former farm house there is a small grove of these trees, probably planted. These may have been the source for some of the young trees on the Reservation.
On several occasions cardinals (Richmondena cardinalis) were observed to have nested in the young cedars, whose thick foliage provided well sheltered nesting sites. This shelter was utilized especially in early nestings when foliage had only begun to appear on other trees and shrubs. However, two such nests in cedars, that were checked repeatedly, were eventually destroyed by predators.
Salix nigra.—Black willow is localized in the vicinity of the one small pond on the Reservation. The pond was made in 1936; atthe upper end of a small valley a dirt bank 100 yards long was built across a ravine through which an intermittent creek drained. Hilltop fields draining into this ravine were then under cultivation. In the next few years heavy erosion occurred in the upland fields, and the soil carried downstream was deposited in the pond. Most of the pond was filled up with a silt flat about an acre in area. On the higher part of this silt flat a dense thicket of saplings of elm, honey locust and osage orange sprang up. On the lower, wetter part of the silt bar a willow grove grew up, dominated byS. nigra, withS. eriocephala,S. interiorandS. amygdaloidesin smaller numbers. By 1955 some of these trees had attained a trunk diameter of eight inches and a height of thirty feet. Elsewhere on the Reservation, willow is represented only by a few scattered trees and bushes along the two intermittent creeks. The silty soil preferred by the willow is scarce as both streams are actively eroding their channels.
The moist, silty soil beneath the willow grove is covered with a dense mat of low vegetation including giant ragweed, carpenter's square, dayflower, and rice cutgrass. Short-tailed shrews, house mice (Mus musculus), harvest mice and cotton rats thrive in this habitat. Red-winged blackbirds (Agelaius phoeniceus), yellow-billed cuckoos (Coccyzus americanus), red-eyed vireos (Vireo olivaceus), catbirds (Dumetella carolinensis) and Kentucky warblers (Oporornis formosus) use it for nesting. The high humidity and dense vegetation in this grove render it favorable habitat for recently metamorphosed frogs and toads, especially the tree frog, which is sometimes extremely abundant there in summer.
Populus deltoides.—Cottonwood is one of the less common trees on the area, but it attains a larger size than any of the other kinds. The larger of the two creeks on the Reservation is lined with mature cottonwoods along the lower part of its course. Along the smaller creek large cottonwoods are also present but they are more widely spaced. A few cottonwoods are present at well scattered points on slopes and hilltops, usually in forest edge situations or in woodland where other trees are sparse. By far the largest tree on the Reservation is a cottonwood of 15-foot circumference (Plate 7), growing on a hilltop near the south boundary of the Reservation, at the edge of woodland adjacent to a cultivated field.
The heavy rainfall of 1951 resulted in the establishment of hundreds of cottonwood seedlings, mostly in places remote from the mature trees. So far as observed, all these were in recent silt deposits. Many of them have survived the drought of 1952-1954.
Because of their great height, towering above the level of the surrounding tree-tops, cottonwoods are preferred look-out perches of certain of the larger birds, notably red-tailed hawks (Buteo jamaicensis), barred owls (Strix varia), and crows (Corvus brachyrhynchos). Flocks of robins (Turdus migratorius) and of rusty blackbirds (Euphagus carolinus) preparing to roost have been noted habitually to gather in the tops of tall cottonwoods. In spring, large wandering flocks of goldfinches (Spinus tristis) have been seen feeding on the leaf buds of cottonwoods. Baltimore orioles (Icterus galbula) and yellow-billed cuckoos often forage in cottonwoods. Red-bellied woodpeckers (Centurus carolinus) spend a disproportionately large amount of their time in cottonwoods. These woodpeckers have been observed nesting in the hollow branches on several occasions. Downy woodpeckers (Dendrocopos pubescens) also have been noticed foraging in cottonwoods on many occasions. Certain large isolated cottonwoods along creeks were favorite stopping places of blue jays (Cyanocitta cristata) which, on trips from one wooded hillside to another, usually perched briefly in the tops of these tall trees. Calling and looking about, the jays seemed to maintain contact with distant mates or members of the flocks by using these high perches. Often after a brief pause in the top of the cottonwood they flew off in a new direction.
Both woodrats and opossums have been known to utilize hollow cottonwoods as dens. Fox squirrels have been seen climbing in cottonwoods occasionally.
Juglans nigra.—Black walnut is one of the more prominent hardwoods. Under original conditions, evidently many of the larger trees were of this species. Being the most valuable timber species of the area, walnut has been subjected to heavy cutting over the past 85 years. Most of the walnut trees still present are small or medium-sized, but the species is still abundant over much of the area. Along certain hilltop edges there are groves of walnuts, growing in nearly pure stands, with an occasional elm, ash, coffee-tree or honey locust. Elsewhere walnut trees are more scattered, but are distributed throughout the woodland. Although the walnut trees growing in woods are of various sizes from those of mature size down to saplings, seedlings are to be found mainly in fields near the woodland edge. In these situations it is one of the more prominent of the woody species invading open lands. The seeds evidently are transported mainly by rodents, especially fox squirrels.
In autumn every walnut tree that is bearing nuts becomes a focalpoint of activity for squirrels. Over a period of weeks the squirrels concentrate their attention on the walnut crop, continuing until virtually every nut has been harvested. Walnut seems to be the one most important food source, for both the fox squirrel and the gray squirrel. Most of the nuts are stored for future use. Many buried separately and never retrieved by the squirrels, grow into new trees.
White-footed mice often store the nuts in their nests, in burrows, beneath rocks or in crevices. In summer, groves and isolated trees of walnuts are favorite haunts of the yellow-billed cuckoo, which finds concealment in the thick foliage, and probably feeds upon the tent caterpillars that commonly infest these trees.
Carya ovata.—Shagbark hickory is one of the more important hardwoods of the area. The trees are relatively small compared with the larger oaks, elms, ashes and hackberry. However, on several parts of the area this hickory is dominant. It grows mainly on north slopes and hilltops. The trees most frequently associated with it are black oak, American elm and chestnut oak. Scattered through the woodlands are occasional mature hickories of DBH 18 inches or more. However, many of the trees are six inches or less DBH and a large proportion of these have originated as stump sprouts from trees cut in the early thirties or before.
Shagbark is especially tolerant of shading. Numerous young trees and seedlings noted all were growing in dense woods of larger hickories, oaks, or mature elms. None has been found in open fields or even in edge situations. This hickory is resistant to drought; relatively few died during the drought of 1952-1954, and these were mostly small trees in crowded stands.
In parts of the woodland dominated by shagbark hickory the trees are mostly 5 to 6 inches or even smaller in trunk diameter and 20 to 30 feet high, sometimes growing in nearly pure stands, and with a leaf canopy so dense that shrubs and herbaceous vegetation are sparse.
The mast crop produced by shagbark is an important food source for both fox squirrels and gray squirrels. Both kinds of squirrels often use these hickories as sites for their stick nests. White-footed mice also store the nuts as a winter food source.
Birds which are most often seen in groves of shagbark include the yellow-billed cuckoo, tufted titmouse (Parus bicolor), black-capped chickadee (P. atricapillus), blue jay, summer tanager (Piranga rubra), and red-eyed vireo. The Cooper hawk (Accipitercooperii) has been recorded nesting in this hickory. In dead trees of this species that are still standing, the interiors may decay more rapidly than the armorlike bark plates. On several occasions tufted titmice and chickadees have been recorded as nesting in such cavities.
Quercus stellata.—Post oak is relatively scarce on the Reservation. One area of approximately an acre on a south slope is dominated by it. There are several other small groves and scattered trees. All are on moderately steep south slopes in poor soil. Trees often found associated with it include red elm, chestnut oak, chinquapin oak, blackjack oak, hickory, and dogwood. It seems likely that under original conditions this species occupied about the same area as it does at present. It is not spreading, and there are few young trees anywhere on the area. In every instance the groves are limited to a rocky clay soil, and edaphic factors obviously are of major importance. Under original conditions fire was probably a limiting factor, and at the present time competition with other hardwoods may be even more important.
Quercus macrocarpa.—Less than a dozen individuals of mossycup oak have been noticed on the area, at well scattered points. Under original conditions, it probably grew chiefly in the bottomlands that have been completely cleared of timber for cultivation. The few now present are all on hillsides, and are medium to large trees.
Quercus Muehlenbergii.—Chestnut oak was perhaps the one most important tree species of the original climax forest on the area. Because of its slow growth, scanty seed production, and large heavy fruits with seeds lacking effective dispersal mechanisms, it has lost ground to other kinds of trees as a result of the unnatural disturbances which have occurred.
It still dominates on rocky upper slopes that have north, east or west exposures and forms nearly pure stands in limited areas. Nearly all the larger trees of this species now present have been cut one or more times and have regenerated from stump sprouts. Seedlings and young saplings of this oak are scarce even in parts of the woodland where the species is most common. It is evident that reproduction is slow, at least under present conditions. On the lower hill slopes these oaks are scarce and scattered, but some of the largest are in such situations. Chestnut oak seems to be relatively resistant to drought. In the summer of 1954 when elms, and especially black oaks of all sizes were dying in large numbers, thechestnut oaks growing among them showed little evidence of injury in mature trees and only a small percentage of mortality in saplings.