The vegetation in Pakistan is divided into five categories on the basis of climate, altitude and plant types. These are:
- Dry tropical forest vegetation
- Dry sub-tropical sub-mountainous vegetation
- Dry Temperate forests vegetation
- Moist temperature forest vegetation
- Sub –Alpine and Alpine vegetation
- Dry Tropical Forest Vegetation
Greater part of Pakistan has tropical conditions. The dry tropical forests are distributed in the tropical coastal area, Indus plan, and Low hills of Baluchistan and Sind. Their vegetation chiefly consists of xerophytes. Biotic communities are developed on large tract of land. This land is used for agriculture. Dry tropical forests are classified as follows:
(a)Dry Tropical Thorn Forest Vegetation (Indus plain and hills): They are distributed in Indus basin plains of Punjab. Sind, and coastal region of Pakistan. The hills are scattered throughout the Indus plain. Some of plants are Prosopis julillord Prosnpis cineraria Acacia Mimic° (kikar) and Acacia senegal.
(b)Vegetation of Riverian Tract and Indus Delta: The area present around the river is called riverain tract. Some of plants found in this area are Saccharum numja (sarkanda), Taunt inc//ca etc. The tract where rive enters into sea is called delta. The delta has forests of mangroves.
(c) Vegetation of Sandy Tracts: Sandy tract includes Thal, Cholisten and coastal tract of Makran and Sind. The average rain fall in these regions is 6 -12 inches. Some of the plants in these regions are Salvadora, Acacia and Euphorbia.
(d) Vegetation of Irrigated Plantation: Canal system is developed in the Indus basin region of Pakistan. This area was included in Tropical rain forests. These forests have been cleared and its land is used for agriculture.
- Dry sub-tropical sub-mountainous vegetation
This vegetation includes trees and shrubs. The trees may show dense growth. The trees and shrubs are thorny. The average rain fall in this region is 10 – 36 inches. Humidity is low. The annual mean humidity is 50%. Temperature rises to 40°C in summer. This area includes Siwalik Hills and Baluchistan Plateau.
(a) Vegetation of Siwalik Hills: Siwa;ik Hills include Potohar plateau, salt range and hills of the NWFI’. Some of plants found in this regions are Acacia modems, (Rea cuspidate, Dalbergia sissy etc.
(b) Vegetation of Baluchistan Plateau: This area is distributed in dry hills, sand dunes and coastal low hills of Baluchistan. They have xerophytic plants. The plants found in these areas are Juniperous, Mentha, Tamarix etc.
- Dry Temperate forests
They have unfavourable climate. Thus they have less number of plants. Most of this area has bare soil. Here plants are mostly Xerophytic. This region includes Suleiman Range, Koh Safad Range, Koh Hindu Kush Range, Karakoram Range and lower part of the Neelam valley (Azad Kashmir). This region has long cold winter. Temperature becomes lower than zero. The annual total rain fall is less than 30 inches. Some of these areas are covered by snow. Thus most of this area is a zone of winter rain and snow.Some of the genera found in this region are Juniperous, Frarinus. Prunus, Stipa, Dodonoea FFagraria Minn, Ephcdra and Rumex.
- Moist Temperate Forest
These are found along the Himalayan Mountains. They are located in Kashmir, Murree -Hazara hill tract, Swat, Dir, Gilgit and Baltistan districts.
These mountains receive heavy monsoon rain fall during July to September. Annual rain 30 to 60 inches. Most of precipitation takes place in the form Of snow. Snow fall may reaches up to 15 feet.
The melting of snow provides adequate moisture. Average humidity is 57%. Temperature ranges between -25 to 30’t.
These are coniferous. forest. they contain coniferous plants like Pinus roxburghit Pious wallichiono. Texas wollichiana. Abies pindrow.
Cedrus deodara etc. Some broad leave plants are also present there. These are apple, Almond, Apricot etc.
There is heavy grazing and trampling in these forests. Therefore, most of the moist forests have been destroyed. These forests are replaced by small grasses, some legumes and some members of Liliaceae. These flat grassy grounds are called parklands. They are mostly found in Murree. Kaghan valley and upper Swat.
- Sub alpine and Alpine vegetation
The vegetation zone above the moist temperate coniferous forest is called sub-alpine and alpine region. It is found in Himalayan Mountains of Kaghan. Swat, lialtistan. Gilgit AgenL.), Chitral, Dir and Kurram Agency.
The growing season is short in these zones. Thev had deep snow and cold wind. So they have xerophytic habitat tor plants. These zones are away from the monsoon region. therefore. annual rain fall is very low . Thus rain bill ranges between 4 — 26 niche!, Maximum temperature is
Belida mulls is characteristic mid doininant specie of sub-alpine region. It attains height 420 feet. Sonic other deciduous tree genera are ,Xorhlly and Sal lx. Alpine vegetation is composed of deciduous and small leaved species. Growing period is shorter. Most common plants found in alpine zone are genera of Arenaria, Salix, Berberis, Polygonum etc.