GS Notes

1.5 - Geography Notes 43

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Elaborate Notes

Tropical Dry Evergreen Forests

  • Climatic Conditions and Distribution: These forests are unique to the Indian subcontinent, primarily found along the Coromandel Coast of Tamil Nadu and Andhra Pradesh. Their existence is dictated by the rainfall pattern of the region, which receives its primary precipitation from the retreating North-East Monsoon during the winter months (October to December), while the summer remains relatively dry. This reversal of the typical monsoon pattern is the key determinant of this vegetation type.
  • Botanical Characteristics: Despite the name “evergreen,” these forests are not as dense or tall as tropical wet evergreen forests. They are characterized by a mix of hardy, broad-leaved evergreen trees that have developed adaptations to withstand the long dry season. The canopy is typically low, around 10-15 meters. The trees have fragrant flowers and often bear fleshy fruits, attracting a variety of birds and animals.
  • Key Species and Their Significance:
    • Neem (Azadirachta indica): A tree deeply embedded in Indian culture and traditional medicine (Ayurveda). Its oil, leaves, and bark have antiseptic and medicinal properties.
    • Tamarind (Tamarindus indica): Valued for its fruit pulp, which is a staple in South Indian cuisine, and its hard, durable wood.
    • Jamun (Syzygium cumini): Known for its fruit, which has medicinal properties, particularly in managing diabetes.
    • Toddy Palm (Borassus flabellifer): A significant source of livelihood, providing sap for palm wine (toddy), fruits (nungu), and leaves for thatching and handicrafts.

Tropical Deciduous Forests

These are the most widespread forests in India, also known as monsoon forests. They are characterized by trees that shed their leaves for about six to eight weeks during the dry season to conserve water. This classification is primarily based on rainfall, as proposed by H.G. Champion and later revised with S.K. Seth in their seminal work, ‘A Revised Survey of the Forest Types of India’ (1968).

  • Tropical Moist Deciduous Forests

    • Climatic Conditions: Found in regions receiving annual rainfall between 100 cm and 200 cm. They represent a transition between wet evergreen and dry deciduous forests.
    • Characteristics: These forests are dense with a multi-layered structure, similar to evergreen forests, comprising tall trees, a shorter understorey, and a shrub layer. The diversity of species is high.
    • Distribution: They occupy a large area, including the foothills of the Himalayas, the eastern slopes of the Western Ghats, and the wetter parts of the Chota Nagpur Plateau (Jharkhand, Odisha, Chhattisgarh), West Bengal, and the Andaman & Nicobar Islands.
    • Key Species:
      • Teak (Tectona grandis): Highly prized for its durable, water-resistant timber, used in furniture and shipbuilding. It thrives in Central India but is sensitive to frost, which limits its growth in the northern plains.
      • Sal (Shorea robusta): Another dominant and economically important timber species, especially in North and East India. It is more tolerant of cold and often replaces teak in the northern plains.
      • Sandalwood (Santalum album): A parasitic plant known for its fragrant heartwood. It requires a host plant to derive nutrients and takes 30-40 years to mature. Karnataka is the primary producer.
      • Sheesham (Indian Rosewood - Dalbergia sissoo): A premium timber tree found in North India, valued for high-quality furniture.

  • Tropical Dry Deciduous Forests

    • Climatic Conditions: These forests are found in areas with annual rainfall between 70 cm and 100 cm. They face a longer dry season compared to their moist counterparts.
    • Characteristics: The forest is less dense, with a more open canopy, allowing for the growth of a grassy understorey. Species diversity is lower. As rainfall decreases, these forests transition into thorn forests.
    • Distribution: They cover a vast expanse of the country, from the foothills of the Himalayas to Kanyakumari, occupying the rainier parts of the peninsular plateau and the plains of Uttar Pradesh and Bihar.
    • Key Species:
      • Bamboo (Bambusa spp.): Legally classified as a ‘tree’ under the Indian Forest Act, 1927, for regulatory purposes within forest areas. The Indian Forest (Amendment) Act, 2017, amended this to classify bamboo grown in non-forest areas as a ‘grass’, exempting it from felling/transit permits and boosting the bamboo industry.
      • Red Sanders (Pterocarpus santalinus): An endemic species found in a restricted geographical range in the Eastern Ghats of Andhra Pradesh. It is highly valued for its deep red wood, used in furniture and for extracting dye. Its high demand in East Asian markets has led to rampant illegal smuggling, placing it under Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora). It thrives on rocky, degraded, and fallow lands with low rainfall.

Tropical Thorn Forests and Scrubs

  • Climatic Conditions: These are found in regions with less than 70 cm of annual rainfall, characterized by high temperatures and low humidity.
  • Adaptations (Xerophytic): Plants in these forests exhibit adaptations to conserve water, such as long roots to tap deep groundwater, small, waxy leaves to reduce transpiration, and thorns to protect against grazing animals.
  • Distribution: They are prevalent in the semi-arid areas of south-west Punjab, Haryana, Rajasthan, Gujarat, Madhya Pradesh, and the leeward (rain shadow) side of the Western Ghats in the Deccan Plateau.
  • Key Species:
    • Acacia (Acacia spp.): Includes species like Babool (Acacia nilotica), a key source of gum and fodder.
    • Khair (Acacia catechu): The source of kattha, an extract used as an ingredient in paan.
    • Date Palms (Phoenix dactylifera) and Neem (Azadirachta indica) are also common.
  • Note on Invasive Species: Prosopis juliflora (Vilayati Babool) is an invasive species introduced in India. While it has adapted well to arid conditions, it aggressively outcompetes native vegetation, depletes groundwater, and is not a natural component of India’s tropical thorn forests.

Montane Vegetation

Montane vegetation refers to the sequence of natural vegetation zones found in mountains, which change with increasing altitude due to the corresponding decrease in temperature.

  • Altitudinal Zonation in the Himalayas:

    • Foothills (up to 1500m): Characterized by Tropical Moist Deciduous forests (like Sal) in the Terai and Bhabar regions.
    • Temperate Zone (1500m to 3500m):
      • Wet Temperate (1000-2000m): Dominated by broad-leaved evergreen trees like Oak and Chestnut.
      • Coniferous Forests (1500-3000m): Characterized by commercially valuable softwood trees like Chir Pine (Pinus roxburghii), Deodar (Cedrus deodara), Silver Fir, and Spruce. Chir Pine is highly susceptible to forest fires during dry summers due to its resinous content and dry needle-like leaves.
    • Alpine Zone (beyond 3500m): Trees are replaced by shrubs and grasslands.
      • Alpine Grasslands: Known as Bugyals or Payaar in Uttarakhand, these are high-altitude meadows that emerge after the snow melts in summer. They are rich in nutritious grasses and herbs.
      • Transhumance: This seasonal movement of pastoral communities is intrinsically linked to Bugyals. Tribes like the Gaddis (Himachal Pradesh), Bakarwals (Jammu & Kashmir), Bhotiyas, and Gujjars (Uttarakhand, Himachal Pradesh) move their livestock to these high-altitude pastures in summer and return to the valleys in winter.
      • Rhododendron: A prominent flowering shrub found in the sub-alpine and alpine zones, known for its vibrant flowers and cultural significance in Tibetan monasteries.

  • Montane Vegetation in Peninsular India:

    • Found in higher elevations of the Western Ghats (especially the Nilgiris, Anaimalai, Palani hills) and the Vindhya and Satpura ranges.
    • Shola Forests: These are a unique mosaic of montane evergreen forests found in the high-altitude valleys and folds of the terrain, interspersed with rolling grasslands on the hilltops. The low temperatures and frost on the hilltops inhibit tree growth, leading to grasslands, while the sheltered valleys support stunted evergreen forests. This creates a distinct ecological landscape.

Littoral and Swamp Forests (Mangroves)

  • Habitat and Distribution: Mangroves are salt-tolerant plant communities (halophytes) found in the intertidal zones of tropical and subtropical coastlines, typically in river deltas, estuaries, and coastal lagoons where freshwater from rivers mixes with saltwater from the sea. Major mangrove forests in India include the Sundarbans (Ganges-Brahmaputra delta), Bhitarkanika (Odisha), Pichavaram and Muthupet (Tamil Nadu), and the deltas of Godavari (Coringa) and Krishna rivers.
  • Unique Adaptations:
    • Pneumatophores: Specialized aerial roots that grow upwards from the soil to facilitate gaseous exchange in anaerobic (oxygen-poor) waterlogged soil.
    • Stilt Roots: Prop roots that grow from the trunk and branches, providing structural support to the trees in the soft, shifting mud.
    • Vivipary: A reproductive strategy where seeds germinate while still attached to the parent tree. The developed seedling (propagule) then falls into the water and floats until it finds a suitable substrate to anchor itself.
  • Key Species: Sundari (Heritiera fomes), from which the Sundarbans derive their name, Brugeira, and Sonneratia.
  • Ecological and Economic Significance:
    • Coastal Protection: They act as a natural barrier, absorbing the energy of storm surges, cyclones, and tsunamis, thereby protecting coastal communities.
    • Biodiversity Hotspot: They provide critical habitat for a wide range of fauna, including the Royal Bengal Tiger (which has adapted to swim and hunt in the Sundarbans), Fishing Cat, Saltwater Crocodile, and numerous species of birds, fish, and crustaceans.
    • Carbon Sequestration: Mangroves are highly efficient at sequestering atmospheric carbon, storing it in their biomass and soil (termed “Blue Carbon”) at a rate several times higher than terrestrial forests.
    • Livelihoods: They support coastal communities by providing timber, fuel, and serving as breeding grounds for commercially important fish and shellfish.
  • Threats and Conservation: Mangroves face threats from coastal development, aquaculture expansion, pollution, and changes in freshwater flow. The Government of India launched the MISHTI (Mangrove Initiative for Shoreline Habithabitats & Tangible Incomes) scheme in the 2023-24 budget to promote mangrove plantation along the coastline.

World Agriculture Types

The classification of agricultural systems, pioneered by geographers like Derwent Whittlesey in his 1936 work “Major Agricultural Regions of the Earth”, helps understand the relationship between environment, culture, and economy.

  • Nomadic Herding: The most primitive form of pastoralism, where communities move with their livestock in search of pasture and water. It is practiced in arid and semi-arid regions of Africa, West and Central Asia. The choice of animal depends on the region: camels in the Sahara, yaks in Tibet, and reindeer in the tundra. It is a subsistence activity where communities rely on animals for milk, meat, and hides.

  • Shifting Cultivation (Slash-and-Burn): A traditional, subsistence agricultural system practiced by indigenous communities in tropical rainforests. A patch of forest is cleared and burned; the ash provides initial nutrients to the soil. Crops are grown for a few years until soil fertility declines, after which the plot is abandoned and a new one is cleared. It is known by various names: Jhum in North-East India, Ladang in Malaysia, and Milpa in Central America.

  • Intensive Subsistence Agriculture: This system is characterized by high inputs of labor on small, often fragmented plots of land to maximize yield per unit area. It is prevalent in densely populated monsoon regions of Asia. There are two main types:

    • Wet Rice Dominant: Practiced in river valleys and deltas with abundant water (e.g., Ganga-Brahmaputra delta).
    • Other than Wet Rice Dominant: Practiced in areas with less rainfall, where crops like wheat, soybean, and sorghum are grown. Productivity per hectare is high, but due to the high population density, per capita output is low.

  • Plantation Agriculture: A form of commercial farming introduced by Europeans in their tropical colonies. It involves large estates (plantations) focusing on a single cash crop (monoculture) for export. It is capital-intensive, requires a large labor force, and employs scientific management. Examples include tea plantations in India established by the British, rubber in Malaysia, and sugarcane in the Caribbean.

  • Mediterranean Agriculture: A highly specialized commercial agriculture practiced in regions with a Mediterranean climate (hot, dry summers and mild, wet winters). It is known for viticulture (grape cultivation) and the production of citrus fruits (oranges, lemons), olives, and figs.

  • Extensive Commercial Grain Farming: Practiced in the temperate grasslands (Prairies of North America, Steppes of Eurasia, Pampas of Argentina, Downs of Australia). It is characterized by:

    • Extensive Scale: Very large, mechanized farms.
    • Monoculture: Primarily focused on wheat.
    • Soil: Often found on fertile Chernozem (black earth) soils, rich in organic matter.
    • Productivity: Low yield per hectare, but due to the massive scale and low population, the per capita output is very high.

  • Commercial Livestock Ranching: The commercial grazing of livestock over extensive areas. Unlike nomadic herding, it is a scientifically managed, sedentary activity focused on producing meat, wool, and hides for the global market. Ranches are large, permanent establishments, common in temperate grasslands like the American West and the Australian Outback.

  • Mixed Farming: An integrated system where crop cultivation and animal husbandry are practiced on the same farm. Crops like maize and barley are grown for both human consumption and as fodder for livestock. This system provides income security and helps in maintaining soil fertility through the use of manure. It is common in Western Europe and eastern North America.

  • Commercial Dairy Farming: The most advanced and efficient type of animal husbandry, focused on milk and milk products. It is highly capital-intensive (requiring investment in storage, milking machines) and located near urban centers due to the perishable nature of its products. Key regions include North-West Europe and North-East USA.

  • Truck Farming (Market Gardening): The specialized cultivation of high-value, perishable products like vegetables, fruits, and flowers, exclusively for the urban market. The term ‘truck’ refers to the fact that farms are located at a distance from the city that can be covered overnight by truck.

Indian Agriculture: Land Use Categories

Land use data in India is maintained by the Land Revenue Department. Understanding these categories is crucial for agricultural planning and resource management.

  • Forest: Area legally classified as forest, whether it has actual tree cover or not.

  • Area under Non-agricultural Use: Land occupied by settlements (rural and urban), infrastructure (roads, railways), industries, etc.

  • Barren and Wasteland: Land which cannot be brought under cultivation with available technology, such as desert, rocky terrain, or ravines (e.g., Chambal ravines).

  • Permanent Pastures and Grazing Lands: Land set aside for grazing, mostly owned by village panchayats or the government.

  • Net Sown Area (NSA): The total physical area on which crops are sown and harvested in a particular year.

  • Gross Cropped Area (GCA): The total area sown with crops, where the area is counted as many times as crops are grown on it in a year. For example, if a farmer grows two crops on a 2-hectare plot in a year, the NSA is 2 hectares, but the GCA is 4 hectares.

  • Cropping Intensity (CI): A measure of how intensively a piece of land is being cultivated. It is calculated as: CI = (GCA / NSA) x 100. A higher CI indicates multiple cropping.

  • Current Fallow: Land left uncultivated for one agricultural year or less to allow it to recoup fertility.

  • Fallow other than Current Fallow: Land left uncultivated for more than one year but less than five years.

  • Culturable Wasteland: Land that has been left fallow for more than five years. It is capable of being cultivated but is not currently used for it.

  • Trends in Land Use:

    • Increase in Forest Area: Due to afforestation programs and better demarcation, the area legally classified as forest has shown a marginal increase, although the quality of this forest cover is a separate issue.
    • Increase in Area under Non-agricultural Use: This is a direct consequence of rapid urbanization, industrialization, and infrastructure development.
    • Decrease in Culturable Wasteland and Fallows: As population pressure on land increases and agricultural technology improves, more of this land is being brought under cultivation, leading to a slight increase in the Net Sown Area.

Prelims Pointers

  • Tropical Dry Evergreen Forests: Location - Coromandel Coast (Tamil Nadu, Andhra Pradesh); Rainfall - Winter (Retreating North-East Monsoon).
  • Tropical Moist Deciduous Rainfall: 100-200 cm.
  • Tropical Dry Deciduous Rainfall: 70-100 cm.
  • Tropical Thorn Forest Rainfall: Less than 70 cm.
  • Sandalwood (Santalum album): A hemi-parasitic tree, primarily found in Karnataka.
  • Red Sanders (Pterocarpus santalinus): Endemic to Eastern Ghats of Andhra Pradesh; listed in CITES Appendix II.
  • Bamboo: Legally a ‘tree’ in forest areas (Indian Forest Act, 1927) and a ‘grass’ in non-forest areas (Amendment, 2017).
  • Montane Vegetation Zonation (Himalayas):
    1. Up to 1500m: Deciduous
    2. 1500-3500m: Coniferous (Pine, Deodar)
    3. Above 3500m: Alpine Vegetation (Bugyals)
  • Bugyals: High-altitude alpine grasslands in Uttarakhand.
  • Transhumance Tribes: Gaddis, Bakarwals, Bhotiyas, Gujjars.
  • Shola Forests: Montane evergreen forests in valleys, interspersed with grasslands on hilltops, found in the Nilgiris and other parts of the Western Ghats.
  • Mangrove Adaptations:
    • Pneumatophores: Aerial breathing roots.
    • Stilt Roots: For support in mud.
    • Vivipary: Seed germination on the parent tree.
  • Major Mangrove Sites: Sundarbans (West Bengal), Bhitarkanika (Odisha), Pichavaram (Tamil Nadu), Coringa (Andhra Pradesh).
  • MISHTI Scheme: Government scheme for Mangrove Plantation along the coastline.
  • Chernozem: Fertile black earth soil rich in calcium carbonate, found in temperate grasslands (Steppes) and ideal for extensive wheat farming.
  • Shifting Cultivation Names: Jhum (NE India), Ladang (Malaysia), Milpa (Central America).
  • Land Use Terms:
    • NSA: Physical area cultivated in a year.
    • GCA: Total area sown, including multiple cropping.
    • Cropping Intensity Formula: (GCA / NSA) x 100.
    • Current Fallow: Uncultivated for ≤ 1 year.
    • Culturable Wasteland: Uncultivated for > 5 years.

Mains Insights

GS Paper I (Geography & Society)

  • Interplay of Climate and Vegetation: The distribution of India’s natural vegetation is a clear manifestation of climatic variations, particularly rainfall. This relationship can be analyzed through the west-to-east rainfall gradient (thorn → dry deciduous → moist deciduous → evergreen) and the altitudinal zonation in the Himalayas. This demonstrates how physical geography shapes the biotic environment.
  • Man-Environment Interaction: Practices like transhumance by the Gaddis and Bhotiyas represent a sustainable, symbiotic relationship between human communities and their fragile mountain ecosystem. Conversely, shifting cultivation (Jhum) presents a complex debate: viewed by some as an indigenous, eco-friendly system and by others as a driver of deforestation, highlighting the conflict between traditional livelihoods and modern conservation paradigms.
  • Colonial Legacy in Agriculture: Plantation agriculture is a direct legacy of colonialism. It transformed subsistence economies into export-oriented monocultures, created new labor dynamics (e.g., indentured labor for tea plantations), and integrated local economies into the global capitalist system, the effects of which are visible even today.

GS Paper III (Economy & Environment)

  • Mangroves: The Intersection of Ecology and Economy:
    • Cause-Effect: Coastal development (ports, industries) and aquaculture lead to mangrove destruction. The effect is increased vulnerability to coastal hazards like cyclones and tsunamis (as seen during the 2004 Tsunami), loss of fisheries, and coastal erosion.
    • Policy Relevance: Schemes like MISHTI are crucial not just for environmental conservation but also for building climate resilience and protecting coastal livelihoods. The concept of “Blue Carbon” makes mangrove conservation a key strategy for India to meet its climate change mitigation goals (Nationally Determined Contributions).
  • The Bamboo Debate: Law, Livelihoods, and Ecology:
    • The amendment to the Indian Forest Act classifying bamboo as a grass in non-forest areas is a significant policy shift.
    • Analysis: It aims to boost the rural economy by encouraging bamboo cultivation and reducing regulatory hurdles for farmers and artisans. However, ecologists express concern that this could lead to the promotion of bamboo monocultures at the expense of natural, diverse forests, impacting biodiversity. This highlights the classic development vs. conservation dilemma.
  • Land Use Change and its Implications:
    • The increasing trend of ‘Area under Non-agricultural Use’ at the expense of agricultural land and wastelands is a major concern for food security.
    • Analysis: While urbanization is inevitable, unplanned conversion of fertile agricultural land poses a long-term threat. This necessitates robust land use planning, promoting vertical urban growth, and bringing culturable wastelands under productive use through technological interventions to balance development and agricultural needs.
  • Sustainability in Global Agriculture:
    • A comparative analysis of agricultural systems reveals a spectrum of sustainability. While extensive commercial grain farming is highly productive per person, its reliance on mechanization, fossil fuels, and monoculture raises questions about long-term ecological sustainability.
    • In contrast, systems like Mixed Farming offer a more integrated and sustainable model by recycling nutrients and diversifying income, offering lessons for making Indian agriculture more resilient.

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