Nepal has topographic variation from 150 meters above sea level at the southern border to the highest mountain in the world (Everest at 8 848 m) in the north. Nepal has a tropical climate in the south and temperate and alpine climates in the north. Forest types also varies accordingly
The Terai-Bhabar Region
The southernmost physiographic region of Nepal, called the Terai-Bhaber region, has an average altitudinal range between 150 and 300 m above sea level. It has a tropical climate with the main forest type comprised of sal (Shorea robusta) with smaller proportions of moist evergreen forest, dry deciduous forest, and khair-sisoo (Acacia catechu/Dalbergia sissoo) forest.
The Siwaliks Hills and the Inner Terai Region
The next northern physiographic region includes the Siwaliks Hills and the Dun valleys (also called the Inner Terai in Nepal) and has an altitudinal variation between 300 and 1000 m. It is characterized by a subtropical climate. The major forest types in this region include Schima-Castanopsis forests on the northern slopes of the Dun valley; the subtropical pine ( Pinus roxburghii) forests on the Siwaliks ridges, dry scrubby forests on the southern slopes of the Siwaliks and moist Lauracea forests in the northern moist localities along with patches of sal forest.
The Middle Mountain Region
From 1000 m along the southern foothills of the Mahabharat Range (ridge tops up to 3000 m) to the hills of Nepal to an altitude of 2500 m is called the Middle Mountain Region. It has mostly lower temperate forests. These are mainly broadleaved forests with Pinus roxburghii up to 2000 m and Pinus wallichiana at the higher elevations. The river valleys in this region may be as low as 400 m. and sal forests (also called hill sal, a somewhat less luxuriant variety of Shorea robusta) and other subtropical broadleaf forests can occur here.
The High Mountain Region
This region extends from 2000 to 3500 m above sea level, mostly with upper temperate forests of Quercus semicarpifolia, other broad-leaf forests composed mainly of Rhododendron spp., as well as coniferous forests of Pinus wallichiana, Abies pindrow and Picea smithiana. There is also a narrow belt of Tsuga brunoniana.
High Himal Region
This region mainly has alpine forests of birch (Betula utilis) as well as bushy rhododendrons and junipers. There is little cultivation here and a lot of snow- and rock-covered barren lands.
Source: Forest Fire Situation in Nepal IFFN No. 26 - January 2002, p. 84-86
National Forest Inventory of Nepal has differentiated following forest types:
- Sal (Shorea robusta) forests
- KS/SK-Acacia catechu and Dalbergia sisso forests
- TMH-Tropical mixed hardwoods forests
- UMH-Upper mixed hardwoods forests
- LMH-Lower mixed hardwoods forests
- Q-(Oak) Quercus forests
- B/Bu-(Birch) Betula utilis forests
- A/F-(Fir) Abies spectabilis and Abies pindrow forests
- Td/H-(Hemlock) Tsuga dumosa forests
- Pr/CP-(Chir pine) Pinus roxburghii forests
- Pw/BP -(Blue pine) Pinus wallichiana forests
Source: FRSC/ FINNIDA (1997) "Forest Resources of the Eastern Development Region 1994/95." Forest Resources Information System Project (FINNIDA), Forest Research and Survey Centre, Ministry of Forests and Soil Conservation, Ministry of Forests and Soil conservation, His Majesty’s Government of Nepal, 166 pp.