- The term ‘shola’ is a corrupt form of the Tamil word ‘cholai’ borrowed and incorporated into forest typology. In Tamil the term ‘cholai’ (Malayalam: ‘chola’) refers to a cold place, a thicket etc. All these connotations refer to streams, rivulets and the associated forests.
- The shola forests actually represent continuation of the evergreen forests in response to the elevational gradient, the sequence being: Wet Evergreen Forests > Subtropical Hill Forests > Montane Wet Temperate Forests.
- Sholas are the local name for patches of stunted tropical montane forest found in valleys amid rolling grassland in the higher montane regions of South India.
- Shola forests are tropical Montane forests found in the valleys separated by rolling grasslands only in high altitude (>1500 metres asl) regions within the tropics, and are limited to the southern part of the western ghats.
- The shola-grassland ecosystem is characterised by the dense growth of trees in the depressions and folds of the Ghats surrounded by extensive areas of grasslands. They consist of dwarf trees growing 25-30 feet - vegetation is double layered storey with closed canopy which hardly permits a single ray of sunlight to penetrate in the natural vegetation.
- The shola and grassland together form the shola-grassland complex or mosaic.
- Despite the huge ecological significance, they have not been historically protected because the short, stunted trees have little or no timber value.
Importance of Shola forests
- The shola forests have high water retention capacity than any other soil. These forests absorb the Monsoon rains and they retain them within their soil. The retained water is then slowly released in the year’s course and they form small streams. These streams join to form larger streams which form rivers that feed the entire civilizations in the plains down.
- They are the source of water in rivers live Cauvery, Thamirabarani, Vaigai. These rivers are perennial and they never go dry like the Ganges in North India. River Ganges is perennial because it is fed by a melting glacier all the year round. There is no ice in the Western Ghats and yet these rivers manage to supply water all around the year. The reason behind this is the presence of Shola forests.
- They are the reason for moderate climates for several cities along their foothills. Example – Coimbatore, a city that is near the Western Ghats in Western Tamil Nadu. The city unlike other cities in Tamilnadu enjoys a moderate climate all the year round.
- They are home to several endemic species of plants and animals. Endemic means that they can exist only in that specific region and not found in any other part of the world. Without these forests, they lose their habitat and they will eventually go extinct.
Unique Characteristics of Shola forests
- Sky Islands – The shola forests form unique regions called “Sky Islands” which occur only at higher elevations which are usually isolated and separated from each other and the lowland terrain. The distance of separation may be from a few metres to several hundred kilometers. Each sky island may have a climatic condition that is unique to itself. This leads to a great endemism in plants and animals. They adopt themselves to that climatic condition and they evolve there.
- Climatic climax – The shola forest and grassland complex has been described as a climatic climax vegetation. As the vegetation characteristics vary due to climatic conditions such as frost or soil characteristics. The soil characteristics widely vary between the Shola forest and that of the grasslands surrounding it.The soil of the grasslands are usually poor in nutrition and water retention and hence cannot support the shola species. While, the soil of the shola forests are highly nutritive and they have high water retention capacity.