Forest Types in Odisha

Tropical Moist Deciduous Forests

The tropical moist deciduous forests represent the most extensive and economically valuable forest type in Odisha, occupying the regions receiving 1,500 to 2,000 millimetres of annual rainfall. These forests are concentrated in the districts of Mayurbhanj, Keonjhar, Sundargarh, Sambalpur, Deogarh, Angul, Kalahandi (eastern parts), Koraput, Kandhamal, Gajapati, and Rayagada. The dominant species is sal (Shorea robusta), which frequently occurs in nearly pure stands on well-drained slopes, giving these forests their characteristic appearance. When sal dominance is high, the undergrowth is relatively sparse, with only shade-tolerant grasses and shrubs persisting beneath the canopy.

Associate tree species in these forests include Terminalia tomentosa (asan), Terminalia bellerica (baheda), Pterocarpus marsupium (bijasal or Indian kino), Adina cordifolia (haldu), Lagerstroemia parviflora (sidha), Madhuca indica (mahua), and Anogeissus latifolia (dhauda). The mahua is particularly valued by local communities for its flowers and seeds. The understorey comprises species such as Holarrhena antidysenterica (kurchi), Grewia tiliaefolia, and Indigofera pulchella. Bamboo, especially Dendrocalamus strictus, forms an important component and is extensively harvested for construction, handicrafts, and the paper industry. These forests produce substantial quantities of timber, poles, firewood, and non-timber forest products (NTFPs) that sustain the livelihoods of millions of forest-dependent households.

Tropical Dry Deciduous Forests

The tropical dry deciduous forests cover the relatively drier western and interior parts of the state where annual rainfall drops below 1,300 millimetres and the dry season is more pronounced. Districts such as Bolangir, Nuapada, Bargarh, Sonepur, Jharsuguda, and portions of Kalahandi and Sambalpur host this forest type. The vegetation is more open, with trees typically stunted and widely spaced, and the proportion of thorny species is higher. Teak (Tectona grandis) is the most important species, often occurring in association with Anogeissus latifolia, Boswellia serrata (salai), Diospyros melanoxylon (tendu, whose leaves are used for bidi rolling), Chloroxylon swietenia, and Lannea coromandelica. The ground layer dries up completely by March, and forest fires are a recurrent phenomenon, sometimes deliberately set to promote fresh grass growth for grazing.

These forests provide the commercial supply of tendu leaves, which support a seasonally important bidi-rolling cottage industry employing thousands of people, particularly women, in the western Odisha districts. Salai yields an aromatic resin used in incense and traditional medicine. The timber from dry deciduous forests is generally harder and less valued than from moist deciduous ones, but teak from well-managed areas commands high prices. The problem of degradation is more acute in dry deciduous forests due to the combination of heavy grazing pressure, fuelwood extraction, and the frequent fires that prevent natural regeneration. The Forest Department’s management plans for these areas emphasise protection from fire and grazing, enrichment planting, and soil and moisture conservation works.

Semi-Evergreen and Other Forest Types

Tropical Semi-Evergreen Forests occupy the wettest enclaves within Odisha — the deep valleys, north-facing slopes, and high-rainfall pockets of the Similipal massif, the Mahendragiri Hills, the Niyamgiri range, and the Koraput highlands. These forests have a stratified structure with three distinct tree layers. The upper canopy comprises tall evergreen species such as Artocarpus, Michelia, Mangifera (wild mango), and Syzygium, interspersed with deciduous emergents. The middle storey includes Mesua, Polyalthia, and various Litsea species. The lower storey comprises shrubs and herbs including Strobilanthes and various ferns. Epiphytic orchids, mosses, and ferns drape the branches, and the forest floor is covered with a thick layer of decomposing leaf litter. These forests harbour high biodiversity but are highly localised and vulnerable to clearing for plantation crops and shifting cultivation.

Mangrove Forests of the Bhitarkanika ecosystem represent a distinct littoral forest type, discussed in detail elsewhere. They are dominated by halophytic species including Avicennia officinalis, Avicennia marina, Rhizophora mucronata, Sonneratia apetala, Heritiera fomes, and Ceriops tagal. Tropical Dry Evergreen Forests are rare and found in remnant patches along the coastal sand dunes of Puri and Ganjam, representing a vegetation type more typical of the Tamil Nadu coast. These patches, dominated by Manilkara hexandra and Drypetes sepiaria, have been reduced to scattered groves due to historical clearance for settlements and agriculture. Conservation of these remnant patches is a priority for maintaining Odisha’s botanical heritage.