Shola forest

Geography glossary

Also called: Shola, Shola grasslands · Topic: Natural Vegetation and Forests of India · NCERT: Class 7, Ch 8 "How the Land Becomes Sacred"; Class 11, Ch 5 "Natural Vegetation"; Class 11, Ch 14 "Biodiversity and Conservation"

Meaning

Shola forest is made up of patches of stunted (short, slow-growing) evergreen forest. They grow in sheltered valleys and hollows of the Nilgiri, Anaimalai and Palani hills, with open high grassland all around them. Together, the forest patches and the grassland act like a sponge. They feed the streams and rivers that flow down from the Western Ghats, so the whole mosaic is a key water source for peninsular India.

Explanation

Why sholas grow only in the southern hills

  • The southern hills are close to the tropics.
  • The Nilgiris lie at about 11°N, so the base climate is warm.

  • The hills are mostly about 1,500 m high. Only a few peaks go much higher, such as Anamudi (2,695 m, Anaimalai hills, Kerala) and Doddabetta (2,637 m, Nilgiris, Tamil Nadu).

  • Temperature falls with altitude (height above sea level).

  • Lower slopes carry subtropical forest.

  • Higher levels are cool enough for temperate forest. Sholas grow here.

  • These hills are not tall enough for an alpine or tundra belt. So the highest vegetation is shola and grassland, not mosses and lichens as in the Himalayas.

How the shola-grassland mosaic forms

  • Shola-grassland mosaic means a patchwork of two habitats, forest patches and open grassland, lying side by side.
  • Hollows hold the forest:
  • Sheltered folds (valleys and hollows) are protected from strong wind.
  • They hold more moisture.

  • So evergreen trees can grow there, though they stay stunted.

  • Ridges hold the grassland:

  • Open ridges and slopes face the wind and are drier.
  • Trees do not take hold there, so they stay as high grassland.

Important trees

Tree Type Use / note
Magnolia Native evergreen Part of the natural shola
Laurel Native evergreen Part of the natural shola
Cinchona Economically important Its bark gives quinine, a medicine for malaria
Wattle Introduced (brought in from outside) Its bark gives tannin, used to tan leather. It now spreads into the grassland by itself.

How the water sponge works

  • Soak: the grassland and the shola soil soak up monsoon rain.
  • Store: they hold this water instead of letting it run off at once.
  • Release: they let it out slowly through the year, which keeps hill streams flowing even in the dry season.

Where it occurs

  • Main shola areas, in the southern mountain forests of Kerala, Tamil Nadu and Karnataka:
  • Nilgiri hills: Doddabetta (2,637 m), Tamil Nadu
  • Anaimalai hills: Anamudi (2,695 m), Kerala

  • Palani hills: Tamil Nadu

  • Similar forests also grow in the Satpura and Maikal ranges of central India.

  • Rivers fed: the streams and rivers that flow down from the Western Ghats get their dry-season flow from the shola-grassland sponge.

Don't confuse with

  • Himalayan temperate forests (oak, chir pine, deodar): these form tall belts on a mountain range up to 8,000 m+ at about 27°–36°N. Sholas are small, stunted patches in low southern hills (around 1,500 m, rarely above about 2,700 m) at about 8°–22°N.
  • Alpine pastures / bugyals: these are grasslands above the tree line (the height above which it is too cold and windy for trees) in the Himalayas. The grassland around sholas is high montane grassland in the southern hills, and the southern hills have no alpine belt.
  • Tropical evergreen forests: these are tall, dense rainforests on lowland and lower slopes. Shola trees are evergreen too, but they are stunted, temperate-type and found only in sheltered hollows at higher levels.
  • Wattle as a native shola tree: wattle is listed among the shola's economically important trees, but it is introduced, not native. It invades the grassland and harms the mosaic.

Prelims Hooks

  • Sholas are found in the Nilgiri, Anaimalai and Palani hills. Similar forests grow in the Satpura and Maikal ranges.
  • Shola-grassland mosaic: forest in sheltered hollows, grassland on open ridges and slopes.
  • Tree–product pairs: cinchona gives quinine (for malaria). Wattle gives tannin (for leather). Magnolia and laurel are native evergreen trees.
  • Trap: wattle is listed among shola trees, but it is an introduced species that now invades the grassland.
  • Southern hills vs Himalayas: the southern hills hold only subtropical to temperate belts. There is no alpine or tundra belt.
  • Highest peaks near shola areas: Anamudi (2,695 m, Anaimalai, Kerala) > Doddabetta (2,637 m, Nilgiris, Tamil Nadu).

Mains Points

  • Shola-grassland as water infrastructure (GS-III): the grassland and the shola soil soak up monsoon rain and release it slowly. This keeps peninsular rivers that flow from the Western Ghats running in the dry season. Losing the mosaic means weaker hill streams downstream.
  • Plantations and invasive species (GS-III):
  • Tea, eucalyptus and wattle plantations have replaced much of the high grassland.
  • Wattle spreads by itself into the open grassland that is left.

  • With less grassland, the sponge works less well and dry-season stream flow falls.

  • Restoration approach (GS-I/III): remove invasive species such as wattle. Protect the grassland as well as the forest patches, because the two work together as one water-holding system. Treating the grassland as "wasteland" fit for planting is the core policy mistake.

Related concepts

Read more

Sources

  1. 1Class 7, Ch 8 "How the Land Becomes Sacred"; Class 11, Ch 5 "Natural Vegetation"; Class 11, Ch 14 "Biodiversity and Conservation" (primary)