Lowland forests
Lowland forests
On
the Indo-Gangetic plain at the base of the mountains, an alluvial plain
drained by the Indus and Ganges-Brahmaputra river systems, vegetation
varies from west to east with rainfall. The xeric Northwestern
thornscrub forests occupy the plains of Pakistan and the Indian Punjab.
Further east lie the Upper Gangetic plains moist deciduous forests of
Uttarakhand and Uttar Pradesh and Lower Gangetic plains moist deciduous
forests of Bihar and West Bengal. These are monsoon forests, with
drought-deciduous trees that lose their leaves during the dry season.
The moister Brahmaputra Valley semi-evergreen forests occupy the plains
of Assam.The Terai belt
Above the alluvial plain lies the Terai strip, a seasonally marshy zone of sand and clay soils. The Terai has higher rainfall than the plains, and the downward-rushing rivers of the Himalaya slow down and spread out in the flatter Terai zone, depositing fertile silt during the monsoon season and receding in the dry season. The Terai has a high water table due to groundwater percolating down from the adjacent zone. The central part of the Terai belt is occupied by the Terai-Duar savanna and grasslands, a mosaic of grasslands, savannas, deciduous and evergreen forests that includes some of the world's highest grasslands. The grasslands of the Terai belt are home to the Indian rhinoceros (Rhinoceros unicornis).Bhabhar belt
Above
the Terai belt is an upland zone known as the Bhabhar, a zone of porous
and rocky soils made up of debris washed down from the higher ranges.
The Bhabhar and the lower Shiwalik ranges have a subtropical climate.
The Himalayan subtropical pine forests occupy the western end of the
subtropical belt, with forests dominated by Chir Pine (Pinus
roxburghii). The central part of the range is home to the Himalayan
subtropical broadleaf forests, dominated by the sal tree (Shorea
robusta). They are at the foot of the
Shiwalik Hills
Also
called Churia or Margalla Hills, Sivalik Hills is an intermittent
outermost range of foothills extending across the Himalayan region
through Pakistan, India, Nepal and Bhutan. This region consists of many
sub-ranges. Summits are generally 600 to 1,200 meters (2,000 to 3,900
ft). Steeper southern slopes form along a fault zone called Himalayan
Frontal Thrust (HFT); northern slopes are gentler. Permeable
conglomerates and other rocks allow rainwater to percolate downslope
into the Bhabhar and Terai, supporting only scrubby forests upslope. The
Himalayan subtropical pine and broadleaf forests continue here.Inner Terai or Dun Valleys
The Inner Terai valleys are open valleys north of Shiwalik Hills or nestled between Shiwalik subranges. Examples include Dehra Dun in India and Chitwan in Nepal. Himalayan subtropical broadleaf forests grow here.http://en.wikipedia.org/wiki/Himalayas
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