Sunday, March 5, 2017

Desert Saxaul

Photo: Black Saxaul (Haloxylon ammodendron)
Saxaul is found over a huge area (approx. 450,000 sq. km) of semi-arid and arid ecosystems within Central Asia. These so called cold winter deserts range through Uzbekistan, Turkmenistan, Kazakhstan and into Xinjiang, northwest China & Mongolia. Saxual is ranges in size from 2-8 m tall (in rare cases up to 10-12 m tall). It has a brown trunk 4-10 cm (up to 25cm) in diameter. Its wood is heavy and coarse and the bark is spongy and water-soaked. The branches of the young trees are vivid green (new growth) and hanging and turn brown, grey, or white as the tree matures. Branches formed in the current year are green whereas older branches are brown, or grey to white, the leaves of the plant are reduced to very small cusp-like scales, so that it appears nearly leafless. The inflorescences consist of short lateral shoots borne on stems of the previous year and flowers are bisexual or male, very small, als being longer or shorter than the bracteoles. The leaves are reduced to very small, pointed scales so that the plant appears nearly leafless. The flowers are small and yellow.  Flowers appear from March to April. In its fruit, the perianth segments develop, spreading pale brown or white wings diameter of about 8 mm (the seeds about 1.5 mm). Fruits appearing from October to November. Saxaul burns well and in some places it is the only kind of fuel wood that can be utilised for heating and cooking. It is also an important source of water in the arid regions in which it grows. Its thick bark acts as a water storage organ and drinking water can be obtained by pressing quantities of bark. Its wood is also durable and heavy and is used for building shelters.

A large number of birds including the Saxaul sparrow (Passer ammodendri) live in the ecosystem. They are at 14–16 cm long and weight 25–32 grams making them among the larger sparrow species.  A bird of the deserts, it favours areas with shrubs like the saxaul located near rivers and oases. Though it has lost parts of its range due to the expansion of agriculture, to date it is not seriously threatened by human activities.
 
Photo: Saxaul sparrow (Passer ammodendriSource:Haloxylon