A. Most Tropical Forests:
They are divided into 4 groups and each group is further sub-divided into subgroups which in turn are further splits into formations and associations.
Group 1: Tropical Wet Evergreen Forest:
Such forests found in regions with rainfall over 2500 mm per annum, mostly in western Ghats and along south west of Assam and Cachar. Dipterocarpus and shorea (sal) are the main trees.
Group 2: Topical Semi-Evergreen Forests:
This is found along the Western Ghats adjoing wet ever green forests i.e., in Assam and lower attitudes of Eastern Himalayas, Orissa, Malabar Coast and Andaman’s. Rainfall varies from 200-2500 mm.
Group 3: Tropical Moist Deciduous Forests:
This type of forest is found in typical rainfall range of 1500-2000mm.
In U.P., Bihar, Orissa, North Bengal. Maharashtra, Madhya Pradesh, Karnataka, Tamil Nadu. And Kerala etc. tropical most deciduous forests are seen. These areas are characterized by most teak forests.
Group 4: Littoral and ‘Swamp Forests
These are further subdivided into two subgroups:
(a) The littoral forests and
(b) The tidal swamp forests
(a) The littoral forests occur all along the sea coasts and along the sandy bars of dealtas of the larger rivers.
(b) The tidal swamp forests are further divided into 5 types:
(i) Mangrove scrub, (ii) Mangrove forests, (iii) Salt water mixed forests, (iv) Brakish water mixed forests and (v) Palm swamp.
The Sunder bans (W.B.) and the Bhitar Kanika (Orissa) mangrove forests come under this category.
B. Dry Tropical Forests:
They are divided into three groups:
(1) Tropical dry Deciduous Forests:
All the forests of North India i.e., Bihar, U.P., Punjab, Haryana of non-teak and teak bearing types come under this.
(2) Tropical Thorn Forests:
These are distributed in areas of low rainfall (250-750 mm per annum) in both southern and Northern regions of India i.e., Punjab, Haryana, Rajasthan, U.P., M.P., Maharashtra, A.P. etc.
(3) Tropical Dry Evergreen Forests:
These are dense forests of coriaceous leaved evergreen forests.
C. Montana Subtropical Forests:
These are further divided into three groups.
1. (i) Subtropical Broad leaved hill forests :
(a) Nigeria Subtropical hill forests
(b) South Indian subtropical Hill savannah
(c) Reed brakes
(d) Western subtropical hill forest
(e) Central Indian sub-tropical Hill Forests.
(ii) Northern subtropical Broad-leaved hill forests:
(a) East Himalayan Sub-tropical wet hill forests
(b) Khasi sub-tropical wet Hill forests
(c) Assam subtropical pine forests
(d) Assam subtropical Hill Savannah
2. Sub-tropical pine Forests:
These are found in U.P., H.P. and Assam through out the entire contour of the western and central Himalayas.
3. Sub-tropical Dry Evergreen Forests:
Those forests contain small leaved evergreen trees and shrubs including some thorn species.
D. Montane Temperate Forests:
They are divided into three groups:
(i) Montane Wet Temperate Forest: This type occurs in the east Himalayas from East Nepal to Bengal, Assam and NEFA.
2. Himalayas Moist Temperate Forests:
These forests occur above 1,500 rants and extended unto 3,000 meters in the western and central Himalayas.
3. Himalayan Dry Temperate Forest: These are open forest composed of evergreen conifers and some broad leaved trees. They occur above 1700 metes.
E. Sub-alpine Forests:
These forests occur in Jammu and Kashmir, Himachal Pradesh, Uttar Pradesh, Bengal, Assam and Manipur, They occur at an altituval range of 2,900 meters. And 3,500 meters.
F. Alpine Scrub Forest:
These forests extent from 3,600 mtrs. Above upto tree level. They are well distributed in Kashmir (3,600 mtrs.) West Kumauni in UP (3,800 mtrs), Gharawas (3,700 mtrs) and along western Himalays from 2,900 mtrs. to 4,250 mtrs.