Geography · Ch 5 — Natural Vegetation
Tropical Deciduous Forests
Tropical Deciduous Forests
The photograph shows a dense stand of tall trees, their trunks rising straight and close together. The canopy above is visibly thin and uneven — many branches are bare, with only scattered leaves clinging to them. This is the key visual clue: the trees are in their dry-season state, having shed much of their foliage to conserve water. The ground beneath appears relatively open, with little undergrowth, because the sparse canopy lets in only dappled sunlight.
This image captures the defining rhythm of tropical deciduous forests — the monsoon forest. These trees do not stay green year-round. Instead, they drop their leaves during the prolonged dry spell, a survival strategy that reduces water loss through transpiration. When the rains return, the forest bursts back into full leaf, creating a lush, green canopy within weeks. The bare branches in the photograph, therefore, are not a sign of a dead forest but of a living one waiting for the monsoon. …
Concept First
Tropical deciduous forests are the most widespread natural vegetation type in India. Unlike the dense, evergreen rainforests that stay green all year, these forests shed their leaves for about six to eight weeks during the dry summer. This leaf-shedding is a survival strategy — the trees reduce water loss when moisture is scarce. Because they lose their leaves, these forests are also called monsoon forests, since their growth and greenery are closely tied to the monsoon rains.
Where They Are Found
These forests cover large parts of the country, wherever rainfall is between 70 cm and 200 cm per year. They are found across:
- The eastern slopes of the Western Ghats
- The foothills of the Himalayas
- Large parts of the peninsular plateau — including Odisha, Chhattisgarh, southern Bihar, and parts of Andhra Pradesh
- The northeastern states
The Two Sub-Types
Based on the availability of water, tropical deciduous forests are divided into two main types.
1. Moist Deciduous Forests
These grow where rainfall is between 100 cm and 200 cm. They are found mainly in:
- The eastern parts of the peninsular plateau
- The foothills of the Himalayas
- The eastern slopes of the Western Ghats
- Odisha and Chhattisgarh
Characteristic trees: Teak, sal, shisham, hurra, mahua, amla, semul, kusum, and sandalwood. These forests are dense and rich in species.
2. Dry Deciduous Forests
These grow where rainfall is between 70 cm and 100 cm. They are found in:
- The rainier parts of the peninsular plateau
- The plains of Bihar and Uttar Pradesh
Characteristic trees: Teak, sal, tendu, palas, amaltas, bel, khair, and axlewood. These forests are comparatively less dense and more open than the moist type.
Teak and sal appear in both sub-types — they are the most commercially valuable trees of these forests. The difference between the two sub-types is mainly in density and the mix of other species, not in the complete absence of these key trees.
Why the Trees Shed Their Leaves
The deciduous habit is a direct response to the seasonal climate. During the long dry summer, water in the soil becomes scarce. By shedding leaves, the trees cut down transpiration — the loss of water through leaf surfaces — and thus survive the dry spell. When the monsoon returns, fresh leaves sprout and the forest turns green again.
The Dry Season Appearance
In the dry season, these forests present a striking sight. The trees stand bare of leaves, giving the landscape a brown, parched look. The ground is littered with dry leaves, and the canopy is open, letting sunlight reach the forest floor. This is in sharp contrast to the evergreen forests, which remain lush throughout the year.
Economic Importance
These forests are of great economic value to India. They provide:
- Teak — one of the most valuable timber trees in the world, used for furniture, shipbuilding, and construction
- Sal — a hard, durable timber used for railway sleepers and building
- Sandalwood — prized for its fragrant wood and oil
- Mahua — its flowers are used to make a local alcoholic drink, and the tree has medicinal uses
- Tendu — its leaves are used to wrap bidis (country cigarettes)
- Amaltas, bel, khair, and axlewood — each with its own uses in timber, medicine, or fuel
Because of this rich variety of useful trees, these forests support many forest-based industries and provide livelihoods for local communities.
Quick Comparison Table
| Feature | Moist Deciduous | Dry Deciduous |
|---|---|---|
| Rainfall | 100–200 cm | 70–100 cm |