American chestnut
American chestnut ( Castanea dentata ): Leaf and Nuts
The American chestnut ( Castanea dentata ) is a native to North America deciduous tree species from the genus of chestnuts in the beech family ( Fagaceae ). It is not to be confused with the Buckeyes. It was once the most important forest tree in eastern North America.
Description
The American chestnut tree is reached at stem diameters up to about 1.5 meters, a handsome, fast-growing deciduous tree, the heights of growth to about 30 meters. ( Other sources give heights up to 45 tree crown diameter of up to 30 m and trunk diameter of up to 3 m m, on. )
The leaves of the American chestnut are 14-20 cm long and 7-10 cm wide, which is generally a little smaller and wider than the leaves of the chestnut ( 16-28 cm × 5-9 cm). They can be best determined by the larger and more widely spaced teeth regularly on the leaf margin, as the scientific name dentata - Latin for " toothed " for - implies.
The American chestnut tree is a nut fruit, usually involving three nuts are in a fruit. They are covered with a brown velvety skin in a prickly green shell. The nuts develop in late summer. With the first frost in autumn coat opens and falls to the ground.
Dissemination
Native to the American chestnut in eastern North America. Its original range extends from Maine through southern Ontario to the Mississippi River and from the Atlantic coast to the Appalachian Mountains and the Ohio Valley.
The American Chestnut was in the animal and plant world is of great importance, since the foliage many animals served as fodder, such as the white-tailed deer, the turkey and the extinct passenger pigeon. Also, American black bears are known to eat the nuts for their winter fat storage.
Chestnut blight
The American Chestnut was once a major supplier of timber. In 1904, the Asian bark fungus or " chestnut blight " (an ascomycete the type Cryphonectria parasitica, Syn Endothia parasitica ) - for which the chestnuts are very vulnerable - accidentally introduced with an inventory of setting plants a Chinese ornamental chestnut in the Bronx Zoo in America. While the Chinese chestnut were able to develop with the cancer and immune on the other hand, the American Chestnut is highly susceptible to the fungal disease. The " chestnut blight " spread by virtue of the transmission through the air about 80 km per year. In a few decades, as billions were attacked by American chestnuts. Here, the fungus grows in the cambium and in or under the bark of tree, breaks the water absorption and hence the supply of nutrients. As a result of the infestation stunted the aboveground part of the tree. The stumps survive the disease, since the roots are not attacked and developing new crop sprouts. Furthermore, the tree grows very quickly and in many cases the cancer breaks only be performed after the bark has become rougher, about the tenth year. Until then, the tree has its fruit a few years to fully develop. For these reasons, the species was saved from extinction, but the new plant seeds on the tree stumps are rarely more than 6 feet tall before it attacks the fungus again. It is estimated that within their former range, the American Chestnut accounted for a quarter of the trees accounted for, which corresponds to a total of about 3.5 billion copies. Today there is because the fungus only a few dozen full-grown trees. It is believed that panic logging in the first years of tree disease also had the unintentional destruction of trees consequence that were immune to the disease and thus the development and selection fungus resistant variants was inhibited. Most of the western North America has been spared by the fungus so far. American chestnuts grow up in the far north, for example, in Revelstoke, British Columbia. In Sherwood, Oregon the best preserved trees can be found.
Several North American organizations are trying to breed fungus-resistant American chestnut. One is the American Chestnut Cooperators Foundation, which breeds all the American chestnuts, which have shown a natural resistance to the fungus.
The Canadian Chestnut Council is a Canadian organization that seeks the trees in Canada, primarily in Ontario, to resettle. One more is the American Chestnut Foundation, which fungus-resistant American / Chinese chestnut hybrids crossed with native American chestnut, the characteristics and the genetic structure of the American crop recovered to cross ultimately improved generations together and to obtain a uniform fungus-resistant breeding. The current goal is the reintegration of the species in the wild. 2005, a hybrid tree with high gene portion of the American chestnut was planted on the lawn of the white house that thrives there to this day. The National Arboretum of the United States also shows interest in the American chestnut and uses similar methods of intersection to find resistant hybrids. It is believed that the way is prepared for plant experiments in the wild in about six years. On 18 May 2006, a biologist discovered the Ministry of Natural Resources in Georgia a tree population of approximately half a dozen trees near Warm Springs. One of the trees is 20-30 years old, 13 meters high and it is thought that this is so far the most southern sighted chestnut tree that has the ability to form flowers and fruits. It is believed that these trees do not belong to fungus-resistant species, but perhaps due to the dry and stony local climate or other influences of the environment in which they were found, were able to develop a resistance. Employees of the American Chestnut Foundation will examine the trees and possibly sprinkle with fungus-resistant trees and vice versa. An unusually large (26 m high, 35 cm in diameter) ' Survivor ' was in the Talladega National Park, Alabama found in June 2006. The intrinsic and economic value to locate the American Chestnut back into its former habitat in the forests of the East of the USA, can not be estimated.
Use
In the U.S., the nuts were once an important economic factor, where they were even sold in the larger cities on the streets as it is in some places still practiced during the Christmas period (usually roasted over an open fire, so that the smell is widely recognized immediately). Chestnuts are edible raw or roasted; However, they are preferably roasted. Instead of the American fruit of European chestnut offered at many stores nuts. In order to reach the edible yellowish white substance inside, the brown skin is peeled off. To distinguish them from the poisonous are Buckeyes.
The wood of American chestnut is a valuable hardwood that has however lost by the " chestnut blight " caused mass extinctions its forestry importance substantially. The heartwood has a straight grain and is tough as oak. Although easier to cut and divide absent from the center of the outgoing end grain, such as is available in most other hardwoods. The tree is particularly valuable for commercial use, since the American chestnut grows faster than an oak. Rich in tannins (tannins ), is well protected the wood because of its long durability against decay and was therefore used for multiple purposes, eg for the production of furniture, cattle fences, shingles, construction, flooring, railroad ties, plywood, pulp paper or telephone poles. Also tannins from the bark are used for tanning leather. Although no large trees more are available for processing, much chestnut wood is worked from historical barns in furniture and other accessories. The wood of " verwurmten " Chestnut has been damaged by insects, which was sawn from long dead trees by the fungus. The product resulting from the damage pattern of the wood is renowned for its rustic character.