Fraxinus americana

White ash

The White Ash ( Fraxinus americana) is a species of the genus of ash (Fraxinus ) in the family Oleaceae ( Oleaceae ).

Description

The white ash is ( sometimes up to 40 m ) reaches a tree, the growth heights of up to 26 m. The dark gray bark is usually finely cracked and broken into very small short strips. The tree crown is domed and open. The branches are thin and straight. The buds are light brown, small and conical. The severe and often hanging foliage leaf is 15-30 cm long and imparipinnate with seven leaflets. The 1 to 1.5 cm long stalked leaflets are obovate, acuminate, have a goodly length of up to 15 cm and width of 7 cm. They are dark green above and whitish below. The foliation is in Central Europe after the European ash.

The flowers and fruits resemble this. The white ash is dioecious getrenntgeschlechtig ( dioecious ).

Occurrence

The white ash is the most common and most important forestry Eschenart North America. Its distribution area is located in the eastern half of North America, from northern Florida and eastern Texas in the south to New Brunswick and Ontario in Canada. The white ash makes high demands on the supply of nutrients and soil moisture. It grows along streams and on moist soils and tolerates temporary flooding. In youth it is relatively shade tolerant, but is aged high demands on the light enjoyment. It comes in mixed deciduous forests before with sugar maple, tulip tree, American beech, American sweetgum, pin oak and various Hickorynussarten. It rises in the north down to altitudes of 600 meters, in the south up to 1500 meters.

The white ash was introduced in 1724 to Europe and grows widely in Central Europe.

System

Fraxinus americana was first published in 1753 by Carl Linnaeus in Species Plantarum, 2, S. 1057. Fraxinus americana L. are synonyms for: Fraxinus americana var biltmoreana ( Beadle ) J.Wright ex Fernald, Fraxinus biltmoreana Beadle. Fraxinus americana belongs to the section of the genus Fraxinus Melioides.

Use

The ringporige wood of the white ash is hard, tough, heavy, and very elastic. The sapwood is pale whitish, the heartwood brown. It is similar to the wood of the European ash used.

Pests

The main pest of the white ash is the Asian ash borer ( Agrilus planipennis, emerald ash borer English ). This insect was first discovered in 2002 as a harmful organism at different ash species in the Americas. It is an invasive species of beetle is actually native to Asia and eastern Russia, and was probably well introduced with wood packaging material already in the 1980s or 1990s from there. So far, mainly ash trees in Michigan / USA, Ohio / USA and Ontario / Canada were harmed. It is estimated that now about 60 million white ash trees have fallen victim to the beetle and the insect is considered the most destructive insect pest that has ever occurred in the forests of the United States. The expected economic damage in the decade 2011-2021 is estimated to be at least $ 20 billion.

The rust fungus Puccinia sparganioides attacks the white ash.