Natural Vegetation of Odisha - Overview

Factors Determining Vegetation Pattern

The natural vegetation of Odisha is primarily determined by the interplay of climate, soil, and topography. With an annual rainfall ranging from about 1,100 mm in the western interior to over 1,700 mm in the northeastern highlands, and a temperature regime that varies from the cooler plateaus of Koraput-Phulbani to the hot and humid coastal plains, the state supports a mosaic of forest and vegetation types. The intensity and duration of the dry season — roughly November to May — is the most critical factor, as most of Odisha’s forests are deciduous, shedding their leaves during the dry months to conserve moisture. The recorded forest area of Odisha is approximately 61,204 square kilometres, which constitutes 39.3 per cent of the state’s geographical area — among the highest proportions in India, though the quality and density of this forest cover vary widely.

Floristic Diversity

Odisha’s flora comprises over 2,700 species of flowering plants, including 150 species of orchids, 170 species of grasses, and over 300 species of medicinal plants. The state’s position at the junction of the Deccan Peninsula, the Eastern Himalayas (via Bengal), and the coastal biogeographic zone contributes to this rich species diversity. Endemic species include Hildegardia populifolia, Eriolaena lushingtonii, and various hilltop grasses. The forests also harbour economically valuable species such as sal (Shorea robusta), teak (Tectona grandis), rosewood (Dalbergia latifolia), Indian kino (Pterocarpus marsupium), and bamboo (Dendrocalamus strictus). The Similipal region alone accounts for over 1,000 species of flowering plants and 96 species of orchids, making it one of the richest botanical sites in eastern India.

Major Forest Types

The Champion and Seth classification, adapted for Odisha, identifies five broad forest types within the state. Tropical Moist Deciduous Forests dominate the areas receiving 1,500-2,000 mm of rainfall, particularly in the northern districts of Mayurbhanj, Keonjhar, Sundargarh, and the eastern slopes of the Eastern Ghats. Sal is the dominant tree, often occurring in pure stands, along with associates such as Terminalia, Pterocarpus, Adina, and Lagerstroemia. Tropical Dry Deciduous Forests are found in the rain-shadow zones of the western districts — Bolangir, Kalahandi, Sambalpur, and Nuapada — where rainfall is below 1,300 mm. These forests are more open, with teak, Anogeissus, Boswellia (salai), and Diospyros as common species.

Tropical Semi-Evergreen Forests occur in the wetter valleys and moist slopes of the Similipal, Mahendragiri, and Koraput highlands. They have a multi-layered structure with a mixture of evergreen and deciduous species. Littoral and Swamp Forests, including the mangroves of Bhitarkanika and the Mahanadi delta, constitute a unique ecosystem adapted to saline and waterlogged conditions. Tropical Dry Evergreen Forests, rare in India, are found in small patches along the coastal sand dunes in Puri and Ganjam districts, with species such as Manilkara and Drypetes. Additionally, extensive plantations of teak, eucalyptus, and acacia have been raised by the Forest Department in various parts of the state, which now form a significant component of the forest landscape.

Degradation and Threats

Forest Cover Statistics

According to the India State of Forest Report 2021, Odisha has approximately 52,156 square kilometres of forest cover (about 33.5 per cent of the geographical area), of which about 7,200 square kilometres is Very Dense Forest, 21,700 square kilometres is Moderately Dense Forest, and 23,300 square kilometres is Open Forest. The trend over the past decade has seen a slight increase in total forest cover, primarily through afforestation and plantation activities, though the quality of dense forest has declined in some mineral-rich and Maoist-affected districts. The recorded forest area — the area legally notified as forest — is higher than the actual tree cover, partly because significant portions of notified forest land remain degraded or have been diverted for non-forestry purposes. The State Government has implemented the Odisha Forestry Sector Development Project with international assistance to restore degraded forests and improve the livelihoods of forest-dependent communities.