Biology Reference
In-Depth Information
16
CHAPTER
Actual Data versus
NEWGARDEN: American
Chestnut
The American chestnut (
Castanea dentata
; Fagaceae) was one of the most
important trees of the eastern forests of temperate North America. The
species ranged from Maine to western Tennessee and Mississippi and was
commonly the dominant species on upland, well-drained soils. It was one
of the tallest of the eastern deciduous trees (towering to over 40 m), with
bole diameter at breast height often exceeding 3 m. Chestnut grows rapidly
and provided a prized wood, edible chestnuts, and numerous ecosystem
services (e.g., wildlife and understory plant shelter; leaves, fl owers, and
nuts for food; water runoff control; nutrient capture and cycling).
In the late 1890s, the chestnut blight fungus (
Cryphonectria parasitica
) was
accidentally introduced on imported Chinese chestnut (
Castanea mollissima
)
materials. Unlike American chestnut, Chinese chestnut has a long history of
growing in the presence of the blight. It thus is tolerant of the pathogen and
can act as a carrier of the blight. In contrast, the blight is essentially 100%
lethal for the American chestnut. The blight attack on American chestnuts
was fi rst formally reported in 1906, and by 1940, over 4 billion trees had
succumbed. Fortunately, some of the trees can regenerate via root-crown
sprouts after the main bole dies. However, these sprouts are soon attacked
by the blight, usually well before they reach full maturity. Although these
secondary sprouts then die, they release a new round of sprouts, but
continual re-sprouting proceeds with dwindling resources and declining
reproduction, and it is unlikely that such re-sprouting can maintain the
species over generations. Today, it is rather uncommon to encounter live
chestnut treelets in many eastern deciduous North American forests where
the species was previously dominant.
However, attempts to reintroduce blight-resistant strains of the
American chestnut are currently underway. Return of the native chestnut to
eastern forests would restore many of its previous economical and natural
contributions. Resistant strains (e.g., those being developed by the American
Chestnut Foundation;
http://www.acf.org/)
are being produced as the
Search WWH ::
Custom Search