Product Overview
Oaks are primarily temperate region trees and shrubs numbering approximately 600 species worldwide. Oaks have occupied the nonglaciated landscape of North America since the Cretaceous Period. Fifty oak species are represented in two-thirds of the eastern North American forest cover types and dominate 68 percent of hardwood forests (191 million acres). Oaks have figured prominently in folklore, construction, food sources, medications, and dyes. Great political events have occurred under charter oaks, and Native Americans utilized acorns as food (particularly the sweeter white oaks) and the inner bark as medicine (Q. falcata, Q. ilicifolia, Q. imbricaria, Q. muehlenbergii, Q. rubra, and others). This genus, which includes economically important hardwoods, is also critical for meeting watershed, recreation, and wildlife management goals. The encroachment of urbanization, agriculture, and hydrologic projects continues to negatively impact oak forest types. Such impacts may necessitate the establishment of conservation districts for vulnerable species. Comments in the text associated with conservation status are based upon information compiled by the World Conservation Monitoring Center and published in association with the International Union for Conservation of Nature and Natural Resources (IUCN) in the 1997 IUCN Red List of Threatened Plants (Walter and Gillett 1998). In the southern United States, forest management practices favor conifers replacing hardwood forests in rich bottomlands. A new source of concern involves the threat of displacement of native oaks by exotic species. Forest types are placed at risk with the introduction of non-native insects, diseases, and plants. In 1997, a fungal pathogen (Phytophthora ramorum) was identified as the cause of Sudden Oak Death (SOD) in California. Screening for potential hosts has identified some susceptible species of eastern red oaks. Additional susceptible hosts include commercial nursery stock (rhododendrons, bay laurel, huckleberry, and others), which increase the probability that SOD will spread to eastern North America. As the list of susceptible oak and understory hosts expands, this guide will help fill the need to identify and determine the natural occurrence of specific oak species in eastern North America and document any potential loss of species from states or counties. This field guide provides an illustrated reference for identification of eastern oaks and can be used in several ways. Oak identification can be accomplished by utilizing the leaf keys, cross referencing scientific or local common names in the index, verifying similarities between leaf specimens and the illustrated oak leaf reference charts, and comparing descriptions provided for each species. Distribution maps may also aid in the separation of similar appearing species.
