#Ulmus americana.#--On most parts of the area American elm is the dominant tree. It occurs throughout the woodland, and most of the larger trees are of this species. In each of the fields that were formerly cultivated, and in the pasture areas, there are many saplings. More than one hundred elms of DBH two feet or more have been recorded. Presumably these mostly date back 90 years or more and were already growing on the area when it was relatively undisturbed. On the area the distribution of these large elms corresponds in a general way with the present distribution of the oak-hickory type. The coinciding distribution of the climax species and of the largest trees is believed to reflect the distribution pattern of the original forest, except that clearing was thorough in the bottomlands so that hardly any trees of the climax species, or large trees of any kind remain. Several elms of three feet or more DBH were recorded, and the largest one measured was 46 inches. The largest elms are in alluvial soil near small creeks in the two valleys. Also many large elms grow along the upper slopes, especially along the outcrops of the two main strata of the Oread Limestone. Such sites along the outcrops on open slopes are the first to be invaded. The rock strata are relatively impervious to water, which is held at a depth where it is readily available to the trees. Along rocky upper slopes between the two outcrops, where chestnut oak is abundant, elms are relatively scarce and seem unable to compete successfully. It is noteworthy that elm is not mentioned in several of the descriptions (Taft, 1950; Parks, 1854; Robinson, 1899) of the original forest, even in listings of the species present. It must have been much less prominent until favored by disturbed conditions. [Illustration: Fig. 7. Map of Reservation showing present distribution of the largest American elms, those more than two feet in trunk diameter. American elm is increasing and spreading on the area, and smaller trees are abundant even in former cultivated fields and pastures. Growth rate varies according to site, but these larger trees are, in many instances, 90 years or more in age and most of them are thought to be in the area wooded in the eighteen sixties and before.]