Tropical Semi-Evergreen Forests are basically classified as a transitional type of forest between tropical wet evergreen and tropical deciduous forests. In comparison to tropical wet evergreen forests, these are drier places. The biotic components (producer, consumers, and decomposers) such as the rarest, most threatened, and endangered primate species are found only in these forests. The abiotic factors (climate, temperature, soil, precipitation) such as humid and tropical climate, red soils, and heavy rainfall greatly influence the region. This article will explain to you about Tropical Semi-Evergreen Forests which will be helpful in preparing the Environment syllabus for the UPSC Civil service exam.

Distribution of Tropical Semi-Evergreen Forests

• In India, the tropical semi-evergreen forests are distributed in the Western coast, Assam, the lower slopes of the Eastern Himalayas, Odisha, and Andaman Island.
• The tropical semi-evergreen forests also include the Western Ghats of the of the Indian subcontinent.
• Thus it is one of the world's eight 'hottest hotspots' of biological diversity.

Distribution of Tropical Semi-Evergreen Forests

Climatic Conditions

• The average annual rainfall is 200-250 cm.
• The average yearly temperature ranges from 24 to 27 degrees Celsius.
• The relative humidity level is around 75%.
• In comparison to tropical evergreen forests, the dry season is not as short.

Soil

• Most part of the tropical semi-evergreen forests have red soils, laterites, black soils and humid soils.
• In comparison to silt, the soils are dominated by sand and clay.
• With increasing soil depths, a declining trend in soil organic carbon (SOC) was detected.
• Increased carbon return in the form of litterfall is the result of a dense canopy and thick undercover.
• This will contribute to a large amount of organic matter on the forest floor.

Flora

• Several commercially important tree species can be found in these forests.
• Tree trunks are frequently buttressed and covered in epiphytes.
• The laurel, rosewood, mesua, white cedar, Indian chestnut, champa, and other significant species.
• Teak, Jamun, cashew, hog plum, coral tree, jasmine, and crossandra are some of the indigenous and exotic tree and plant species found in this forest.

Butressed Trunks

Fauna

• Indian Leopard, Indian- giant Squirrel, Lemur, Deer, One-Horned Rhinos, Birds, Great Horn Bill, Bats, Sloth, Scorpions, Snails are prominent here.
• Lion-Tailed Macaque, which is endemic to the Western Ghats region of the tropical semi-evergreen forests, is the rarest, most threatened, and endangered primate species identified here.
• Since evergreen forests tend to decline to semi-evergreen as a result of human interference, semi-evergreen forests are more widespread than evergreen forests.

Lion-Tailed Macaque

Kasturirangan Committee’s Report on the Western Ghats

• According to the Kasturirangan committee report, 37% of the entire area of the Western Ghats, or around 60,000 square kilometres, should be designated as an eco-sensitive area (ESA).
• Karnataka is responsible for 20,668 sq km of the total land, which includes 1,576 villages.
• Mining, quarrying, the establishment of red-category industries, and thermal power projects should all be prohibited, according to the report.
• It is further noted that before approval is granted for these activities, the impact of infrastructure projects on the forest and animals should be examined.
• It further claimed that the UNESCO Heritage designation provides an opportunity to raise global and domestic awareness of the Western Ghats' vast natural resources.
• The 39 sites are spread across the Western Ghats, with Kerala (19), Karnataka (10), Tamil Nadu (6), and Maharashtra (6) being the most numerous (4).

Importance of Tropical Semi-Evergreen Forests

• Tropical Semi-Evergreen Forests plays a significant role in hydrology and watershed management.
• The peninsular Indian states, which derive the majority of their water from rivers that originate in the Western Ghats, have a population of about 245 million people.
• As a result, the region's land and water support the livelihoods of millions of people.
• The rain-laden monsoon winds that sweep in from the south-west during late summer are intercepted by the trees of these forests, which act as a crucial barrier.
• The extraordinarily high amount of biological variety and endemism in these forests is a distinguishing feature.

Conclusion

The distinguishing feature of semi-evergreen forests is the bamboo clumps which are generally found beside the streams across the semi-evergreen forests of south-west India, most likely in regions where agriculture was historically carried. The tropical semi- evergreen forest is facing more anthropogenic and other threats. As a result, the original biome of the ecoregion of these forests is almost non-existent particularly in Odisha. According to previous studies, this has been the case since at least 1968. If the emerging threats of this ecosystem are left untreated, the tropical semi- evergreen forests are expected to lose their diversity.

GS Mains Questions and Model Answers

Q1: Analyze the ecological importance of Tropical Semi-Evergreen Forests in maintaining biodiversity.

Answer: Tropical Semi-Evergreen Forests are vital for biodiversity as they provide habitat for various flora and fauna. The mix of evergreen and deciduous trees supports a wide range of species, contributing to rich biodiversity. These forests serve as a refuge for many endemic and threatened species, fostering ecological balance. Additionally, the complex structure of these forests, with their layered canopy and diverse understory, facilitates various ecological interactions, such as pollination and seed dispersal. By maintaining the habitat's integrity, these forests play a crucial role in sustaining wildlife populations and preserving genetic diversity, which is essential for ecological resilience.

Q2: Discuss the challenges faced by Tropical Semi-Evergreen Forests due to human activities.

Answer: Tropical Semi-Evergreen Forests face significant challenges due to human activities, including deforestation, agricultural expansion, and urbanization. These activities lead to habitat loss and fragmentation, adversely affecting the biodiversity and ecological functions of these forests. Additionally, illegal logging and exploitation of forest resources further threaten the sustainability of these ecosystems. Climate change exacerbates these challenges, altering rainfall patterns and increasing temperatures, which can stress the forest's delicate balance. Conservation efforts are crucial to mitigate these impacts, requiring policies that promote sustainable land use and restoration of degraded areas.

Q3: Evaluate the role of Tropical Semi-Evergreen Forests in the context of climate change mitigation.

Answer: Tropical Semi-Evergreen Forests play a significant role in climate change mitigation through carbon sequestration and storage. By absorbing carbon dioxide during photosynthesis, these forests help regulate atmospheric CO2 levels, thereby contributing to climate stabilization. Their rich biomass not only stores carbon but also supports diverse ecosystems that enhance resilience against climate impacts. Protecting and restoring these forests is essential for achieving global climate goals, as they act as critical carbon sinks. Moreover, these forests influence local climates by maintaining humidity levels and regulating temperatures, further reinforcing their importance in climate adaptation strategies.

Previous Year Questions on  Tropical Semi Evergreen Forests

1. UPSC CSE 2022

Question: Explain the significance of Tropical Semi-Evergreen Forests in India's ecological framework. 

Answer: Tropical Semi-Evergreen Forests hold significant ecological importance in India's environmental landscape. They are critical for biodiversity conservation, housing various species of flora and fauna that are often endemic to these regions. Their rich biomass plays a vital role in carbon sequestration, thus aiding in climate change mitigation. Additionally, these forests contribute to the hydrological cycle, helping maintain soil moisture and preventing erosion. They also provide livelihoods for many indigenous communities through sustainable harvesting practices. By preserving these forests, India can enhance its ecological resilience and promote sustainable development, ensuring that natural resources are available for future generations.

2. UPSC CSE 2022

Question: Discuss the impact of climate change on Tropical Semi-Evergreen Forests in India. 

Answer: Climate change poses significant challenges to Tropical Semi-Evergreen Forests in India. Altered rainfall patterns and rising temperatures threaten the delicate balance of these ecosystems, leading to stress on plant and animal species. Changes in seasonal cycles can disrupt flowering, fruiting, and breeding times, adversely affecting species interactions and survival. Increased frequency of extreme weather events, such as storms and droughts, further exacerbates these impacts, leading to habitat loss and degradation. As these forests are crucial for biodiversity and carbon storage, their decline due to climate change could have profound implications for ecological stability and climate resilience. Protecting and restoring these ecosystems is vital to combat the adverse effects of climate change and ensure ecological integrity.