Trees
Robinia pseudoacacia Linn.
Robinia pseudoacacia Linn.
Description :
A medium sized to large, deciduous tree 30 m in height with an open
crown and a straight bole. There are a variety of growth forms some of which
may be thorny. The leaves are compound 18 to 15 cm long. The bark is thick,
rough, brown and has longitudinal fissures. The flowers are small and occur in
long hanging bunches. They are yellowish to white and fragrant, appearing
between March and June. The pods are small, 2.5 to 3 cm long and 0.5 cm wide.
The pods are hard and usually break open while on the tree scattering the seed.
The pods mature between August and October. The tree is relatively free of
disease and insect problems. In the United States it can be heavily damaged by
borers such as Megacyllene robiniae
and Cyllene robiniae.
It is easily reproduced both from seed and by vegetative means. Good seed crops
are produced annually and seed stores well for several years. Pretreatment of
seed will improve germination. It has a rapid growth rate for 30 years then
slows and by age 50 growth almost ceases. Growth of 4 to 8 m3 /ha/yr
in 44 years old stand has been reported. Sapwood is white, and heartwood is
yellowish or reddish brown having specific gravity between 0.75 and 0.80, and a
calorific value of 4800 kcal/kg. Wood is hard, heavy, and resilient with
straight grains.
Distribution :
The tree is native to the southeast and central United States. Because
of its adaptability it is grown throughout temperate zones in the world. In
Pakistan it has been successfully established in the plains and in the hills of
the Punjab and KP. Plantations are being raised in Gilgit Baltistan. An intolerant tree that grows on a variety of soils
but prefers well drained sites and will not grow on waterlogged sites. The tree
is frost tolerant and will grow in areas with temperatures down to -20°C. It
grows from sea level to 2500 m within a precipitation range of 700 to 1000
mm/yr. It is surprisingly drought hardy and can withstand dry periods of 2 to 6
months.
Uses :
This plant has different
uses. The wood of the plant is very hard it is used in the making of furniture.
It has great value as firewood for wood-burning stoves. Flowers of the plants
are sometimes used to produce a sweet and perfumed jam. This plant is
considered as an excellent plant for growing in highly disturbed areas as an
erosion control plant. The wide spreading root system makes it an
ideal tree for erosion control and soil stabilization. It fixes nitrogen and
its foliage and seed are useful as fodder. An excellent farm
forestry tree. It is also used for charcoal production, fence posts, apiculture
and for ornamental purpose.
(Dirr, 1990)