Floral Biodiversity of Western Ghats

Western Ghats, a 1,600 kilometer mountain range running parallel to India’s western coast, is a global biodiversity hotspot renowned for its extraordinary floral as well as faunal richness. Over 4,000 species of flowering plants are found in this region, of which around 38% or 1,500 species are endemic. The high rainfall, varied terrain, and altitudinal gradients have promoted speciation and nurtured this outstanding floral diversity and endemism over time.

Forest Types and Vegetation

The Western Ghats are covered by four main forest types: wet evergreen, semi-evergreen, moist deciduous, and dry deciduous, all rich in species. Wet evergreen forests, found at 200-1,500 meters elevation in areas with 2,500-5,000 mm annual rainfall, like the southern Agastyamalai-Nilgiri hills, are highly endemic. Semi-evergreen forests, located between 300-900 meters on moist western slopes, also have high diversity and endemism. The more extensive moist and dry deciduous forests, within 900 meters elevation and 2,500-3,500 mm rainfall, link to wetter types and broaden the range of floral diversity. Additionally, unique habitats like high montane grasslands, shola-grass complexes, Myristica swamps, peat bogs, and savanna grasslands above 1,700 meters add to the region’s floral diversity.

Timber Trees of Western Ghats

Western Ghats are known for abundance of timber trees known for their quality wood, used in construction, furniture, and other applications.

Teak (Tectona grandis)

Native to peninsular India along with southeast Asia, teak is a large, deciduous timber tree growing over 30 meters tall. Highly valued for its strong, durable, and weather-resistant wood, it occurs naturally in moist deciduous forests but has been extensively planted. Teak plantations cover many parts of the Western Ghats.

Indian Rosewood (Dalbergia latifolia)

This semi-evergreen tree yields one of the finest cabinet and carving woods. Endemic to peninsular India, its fragrant wood is densely grained. It grows up to 15 meters in moist deciduous forests but is overexploited. Sandalwood plantations have often replaced its habitat.

Indian Mahogany (Swietenia mahagoni)

Native to the Western Ghats moist forests, this handsome evergreen tree has a straight bole and dense crown. Its valuable reddish-brown wood that polishes beautifully is extensively used despite logging bans. It is threatened by habitat loss and illegal felling.

Western Ghats Mahogany (Xylia xylocarpa)

Endemic to the Western Ghats hill ranges, this tree bears fragrant white flowers. Growing up to 18 meters tall, its reddish timber is termite-resistant but prone to splitting. This semi-evergreen species is used for boxes, furniture, and agricultural tools.

Shorea robusta (Sal tree)

Native to moist, deciduous forests, Sal is a large, deciduous hardwood that sheds its leaves in winter. Growing over 30 meters high, Sal regenerates easily but is threatened by resin tapping. Its heavy, termite-resistant wood is used for construction and railways.

Jambolan/Black Plum (Syzygium cumini)

This fast-growing, evergreen tree bears edible astringent fruits. Native to the Western Ghats, it thrives near streams in semi-evergreen and moist deciduous forests. Its durable reddish wood is used for furniture, boats, and tool handles though susceptibility to sap stain limits its use.

Sandalwood (Santalum album)

Sandalwood’s delightful fragrance comes from the heartwood of this small hemiparasitic tree – historically abundant in the central Western Ghats though facing worrisome overexploitation now. Sandalwood plays an integral role in Indian spirituality. However, the challenges of organized cultivation remain despite steady global demand.

Fruit Trees

Some of the important fruit trees of western ghats are as follows:

Jackfruit (Artocarpus heterophyllus)

The jackfruit is native to the moist forests of the Western Ghats. Growing over 30 meters tall, this evergreen tree produces the world’s largest tree-borne fruit. Its huge, spiky fruits can weigh over 30 kg. The edible pulp and seeds are nutritious. The wood is used for furniture, doors and musical instruments.

Mango (Mangifera indica)

Over 1,000 mango cultivars have been developed from wild Western Ghats types.

Coconut Palm (Cocos nucifera)

Ccoconut palm is ubiquitous across moist coastal tracts and hill ranges of the Western Ghats.

Tamarind (Tamarindus indica)

A deciduous tree, the tamarind thrives in drier areas of the Western Ghats. It bears long, bean-like, tartly-sweet brown pods with edible pulp used to flavor foods. Its reddish wood is used for woodwork and cart wheels.

Cashew (Anacardium occidentale)

Though native to Brazil, the cashew nut tree is extensively cultivated on hill slopes of the Western Ghats. This fast-growing evergreen tree bears kidney-shaped nuts that grow attached to the lower portion of its fleshy cashew apples. Its soft wood is used primarily as fuelwood.

Medicinal Plants & Spices

Western ghats are home to hundreds of medicinal plant / spice plant species. Few examples are listed below:

Ornamental and Aesthetic Value

Trees and plants grown for their beauty or unique appearance.

Flame of the Forest (Butea monosperma):

Mid-sized, deciduous, found in drier Western Ghats forests, known for orange-red flowers, medicinal uses, and wood used for timber and tools but termite-prone.

Bamboo (various species):

Ubiquitous in Eastern and Western Ghats, over 125 species in India including high-quality types like Oxytenanthera stocksii and Bambusa bambos, used for construction, furniture, handicrafts.

Nilgiri (Eucalyptus globulus):

Non-native, fast-growing, dominates Nilgiri Hills, used for furniture, poles, paper pulp, but raises environmental concerns.

Banyan Tree (Ficus benghalensis):

Large, shade-giving, with cultural significance, grows from aerial roots enveloping host trees, important in rituals.

Indian Fig Tree (Ficus racemosa):

Large, deciduous, bears red figs, leaves, bark, fruits, latex medicinal, sacred to Hindus, supports wildlife, wood used for various purposes.

Bamboo Orchid (Arundina graminifolia):

Terrestrial orchid, slender stems with white blooms, grows in Western Ghats up to 1,800 meters, sensitive to habitat disturbance.

Indian Tulip Tree (Thespesia populnea):

Fast-growing, evergreen, planted for flowers and shade, yellow-orange tulip-like flowers, rounded fruits, wood used for carving, lumber, pulp, leaves and flowers medicinal.

Cash Crops

Some important commercially cultivated crops for their economic value in western ghats are:

Coffee (Coffea arabica and Coffea canephora)

Western Ghats hills produce world-class Arabicas under rainforest canopy and robust Robustas at lower elevations; India, especially Karnataka’s regions like Coorg and Wayanad, is a key exporter.

Tea Plant (Camellia sinensis)

Grown in the highlands of the Western Ghats in southern states, contributing significantly to global tea trade; tea estates also serve as wildlife habitats, with climate change posing productivity and flavor challenges.

Rubber Tree (Hevea brasiliensis)

Thrives in moist mid-elevation zones of the Western Ghats, not native but responsible for over 90% of India’s rubber production; wet climate favors rain-fed latex production.

Vanilla (Vanilla planifolia)

Fragrant orchid vines producing vanilla beans in Kerala and Karnataka’s forests; vital for global flavoring, yet facing conservation challenges due to habitat loss and reliance on hand pollination.

Unique and Ecological Significance

Some of the plant species that play unique ecological roles or are notable for their rarity or habitat in western ghats are as follows:

Neelakurinji (Strobilanthes kunthiana)

Neelakurinji (Strobilanthes kunthiana) is a plant that abundantly grows in the shola grasslands of the Western Ghats. The Nilgiri Hills, which literally means the blue mountains, got their name from the purplish blue flowers of Neelakurinji. The plant is special because its flowers blossoms gregariously only once in 12 years. Last they blossomed in 2006 and now we need to wait till 2018 to see them again blooming. The twelve year cycle of Neelakurinji flowering was first recorded in the year 1838. There after many scientist groups had done studies on this rare species. The reason for this 12-year flowering cycle is yet to be scientifically established.

Neelakurinji is an endangered plant, all the efforts are being made to protect its habitats. The process of converting Kurinji habitats into plantations in the past decades was the major threat for this plant. The Kerala Government had decided to set up a Kurinji Sanctuary in the Eravikulam area of Munnar. In 2006, the Postal Department had also released a special stamp on Kurinji this year to promote the efforts to save kurinji.

Myristica swamps

The freshwater Myristica swamps are a distinctive ecological community occurring below 600 meter elevation in parts of the Western Ghats. Tree species like the wild nutmeg Myristica fatua and Magnolia champaca thrive in these constantly wet, shaded habitats. Many Myristica species are endemic to these swamps, which support unique aquatic lifeforms too.

Wild Nutmeg (Myristica dactyloides)

This is an evergreen canopy tree growing over 45 meter tall is endemic to certain regions of the Western Ghats tropical wet evergreen forests. Its yellow drupe yields nutmeg. Though cultivated for its spices on a limited scale today, wild nutmeg faces loss of lowland forest habitat.

Gamboge Tree (Garcinia gummi-gutta)

The rounded, pumpkin-shaped fruits of this evergreen tree yield a yellow resin that has long been used as a dye, as well as souring agent in cooking across Kerala and other parts of the Ghats, where the species is native. Today Garcinia gummi-gutta extract is popular for weight management drugs.