Identification of Chestnut Trees

Chestnuts have been cultivated for nuts and wood for thousands of years. The name Castanea is believed to come from Kastanea, a city in Pontus, Turkey. European chestnuts (Castanea sativa) probably survived the ice age in Southern Russia in the Caucasus Mountains, between the Black and the Caspian Seas. They were planted throughout the Roman Empire, and now grow wild in Italy, France, Spain, and Greece. Chestnuts are also important in Asia, where there are four native species (Castanea mollissima, C. henryi, C. seguinii, and C. crenata). In North America, pollen records from the last interglacial period show that American chestnut trees, Castanea dentata, were present on Long Island 30,000 to 50,000 years ago. After the ice had permanently receded (about 13,000 years ago), measurable chestnut pollen was first deposited in the Blue Ridge area of North Carolina. American chestnut trees then spread their range all along the Appalachian mountain range, from Portland, Maine to northern Georgia. Within this area, chestnuts grew in mixed, hardwood forests, usually on high, sandy land, gravel ridges, or mountain slopes that were wholly, or nearly free from limestone. In the last 150 years chestnuts have been planted outside the native range in favorable spots (Michigan, Wisconsin) where they have become dominant forest trees, protected from chestnut blight disease by geography until only recently. Allegheny chinquapins, Castanea pumila, share the southern part of the range with American chestnut from Pennsylvania south. Ozark chinquapins are found on the Ozark Plateau, and Florida and trailing chinquapins are found in northern Florida. Even though the Castanea are divided into separate species, all of the species will cross with each other and produce viable offspring. These “mules” are often malesterile and fail to produce pollen, but the female flowers are capable of receiving pollen and will produce viable nuts. The genetics of this male sterility is not understood; sometimes fertility is restored in subsequent generations and sometimes it is not. Descriptions Chestnuts are deciduous trees with alternate, shortstemmed, prominently veined, oblong leaves that have course to fine pointed marginal teeth or bristles. Male (staminate) flowers are formed in the axils of successive or alternate leaves in early June, in groups of cylindrical catkins (aments) as long as or longer than the leaves. Female (pistillate) flowers form later and on younger wood, at the base of short catkins. The nuts develop in prickly husks called burs (with one r), which open when the nuts are mature (usually mid-September to mid-October). There are seven to ten species identified by taxonomists (depending on whether they are “splitters” or “lumpers”). Quick key