Шығыс Солтүстік Американың қайын ағашы (Betula lenta)

Species of plant

Betula lenta (sweet birch, also known as black birch, cherry birch, mahogany birch, or spice birch) is a species of birch native to eastern North America, from southern Maine west to southernmost Ontario, and south in the Appalachian Mountains to northern Georgia.

Betula lenta is a medium sized deciduous tree reaching tall, exceptionally to with a trunk up to diameter. Heights of 50 feet (15 m) to 80 feet (24 m) are more typical. In younger trees the bark is characteristic of most birches, with smooth bark and distinct horizontal lenticels. It is sometimes mistakenly identified as a cherry tree. In older tree specimens the bark (unlike the more commonly known birches) develops vertical cracks into irregular scaly plates revealing rough dark brown bark patterns. This, however, only occurs in mature, or ancient, trees and these specimens are not often identified by the public as B. lenta due to the difference between the tree's smooth young bark (which the public is most familiar with) and the tree's rough, cracked and plated mature bark. The twigs, when scraped, have a strong scent of wintergreen due to methyl salicylate, which is produced in the bark. The leaves are alternate, ovate, long and broad, with a finely serrated margin. The flowers are wind pollinated catkins long, and the species may live even longer in an undisturbed ancient forest. Due to the cracking and developing of bark plates, a rough age estimate can be determined by how many bark layers a tree has. Generally the tree's smooth young bark begins to split around 40–50 years of age, and then begins to peel off the trunk around the age of 70 80. It is then replaced by another layer of bark, which will begin to peel at around 130–150 years. The third layer will peel when the tree has reached 200–210 years and achieved "old growth" status. This will continue to occur as long as the tree lives, but the individual bark layers become indiscernible after roughly 250 years of age. Black birch seeds at a prolific rate and quickly colonizes disturbed areas. In the Northeastern US in the 1980s, infestations of spongy moths, Hemlock woolly adelgid, and Discula destructiva killed many trees, and their place was taken by black birch.

The wood of black birch is heavy at 47 pounds per cubic foot and is used for furniture, millwork, and cabinets. It is similar to yellow birch wood and often not distinguished from it in the lumber trade. The sap flows about a month later than maple sap, and much faster. The trees can be tapped in a similar fashion, but must be gathered about three times more often. Birch sap can be boiled the same as maple sap, but its syrup is stronger (like molasses). It can be used to make birch beer. Boiling also destroys volatile quantities of wintergreen oil. Deer do not tend to browse young B. lenta allowing trees to grow in areas with high deer populations, Betula alleghaniensis, a close relative of B. lenta, is, however, heavily browsed by deer. This accounts for a lack of B. alleghaniensis and an abundance of B. lenta where deer populations are high. In abandoned fields, B. lenta is often thicket forming and protects trees not resistant to deer browsing.