UPSC Prelims 2023 Q3: Deciduous vs Evergreen Trees — Explained
Consider the following trees:
1. Jackfruit (Artocarpus heterophyllus)
2. Mahua (Madhuca indica)
3. Teak (Tectona grandis)
How many of the above are deciduous trees?
- Only one
- Only two
- All three
- None
Answer: (b) Only two
Statement-wise explanation
- 1: incorrect — Jackfruit (Artocarpus heterophyllus, family Moraceae) is an evergreen tree. Britannica describes it as an evergreen tree native to tropical Asia, with large, stiff, glossy green leaves that stay on the tree all year. It comes from the rainforests of the Western Ghats. Its close relative aini (Artocarpus hirsutus) is a typical tree of the Western Ghats evergreen forests.
- 2: correct — Mahua (Madhuca indica, also called Madhuca longifolia var. latifolia, family Sapotaceae) is a large deciduous tree. Most of its leaves fall from February to April. Its fragrant flowers open in March–April, when the branches are bare or nearly bare. NCERT lists mahua among the main species of the tropical moist deciduous forests.
- 3: correct — FAO describes teak (Tectona grandis) as a large deciduous tree. Over most of its natural range, which covers India, Myanmar, Laos and Thailand, it grows in moist and dry deciduous forests below 1,000 m. It sheds its very large leaves (30–60 cm long) in the dry season. NCERT names teak as a main species of both moist and dry deciduous forests.
How to eliminate
Most of this question can be solved from NCERT. Teak is the textbook example of a deciduous (monsoon forest) tree, so the option 'None' goes first. Mahua is the next anchor. Tribal communities collect mahua flowers from March to May. Collectors burn the dry fallen leaves under the trees to clear the ground, and the tree flowers on bare branches. A tree that drops its leaves in the dry season is deciduous. That leaves only one real decision: jackfruit. Remember that jackfruit is a Western Ghats rainforest tree with thick, glossy leaves that stay green all year, so it is evergreen. Many aspirants pick 'All three' because jackfruit grows across the same warm parts of India as teak and mahua. Where a tree is grown does not tell you its leaf habit. Fact to remember: jackfruit is evergreen, while mahua and teak are deciduous.
Know more
Deciduous vs evergreen describes a tree's leaf habit. Deciduous trees shed all or most of their leaves in one season. In India this is the dry season, usually spring to early summer, and it cuts water loss through the leaves. Evergreen trees shed leaves a few at a time all year, so the canopy never goes bare.
India's forest types (NCERT, India: Physical Environment) follow rainfall closely:
| Forest type | Annual rainfall | Typical trees |
|---|---|---|
| Tropical evergreen | > 200 cm | Rosewood, mahogany, aini, ebony |
| Tropical semi-evergreen | Less rainy parts of evergreen zones | Mix of evergreen and moist deciduous trees (white cedar, hollock, kail) |
| Tropical moist deciduous | 100–200 cm | Teak, sal, shisham, hurra, mahua, amla, semul, kusum, sandalwood |
| Tropical dry deciduous | 70–100 cm | Teak, sal, peepal, neem (more open woodland) |
| Tropical thorn | < 50 cm | Babool, ber, wild date palm, khair, neem, khejri |
The tropical deciduous (monsoon) forests are India's most widespread forest type. The India State of Forest Report 2023 says the tropical dry forest group is the dominant forest type in India.
Trees UPSC likes to test:
- Teak: deciduous, valuable timber, native to India, Myanmar, Laos and Thailand.
- Mahua: deciduous. Its flowers (eaten, and distilled into liquor) and seeds (oil) are important minor forest produce for tribal communities in central India.
- Sal: commonly listed as moist deciduous, although it is leafless only briefly.
- Jackfruit, mango, rosewood, mahogany, ebony: evergreen or evergreen-leaning trees of wet regions.
Trap to watch: the forest type and a single tree's leaf habit are two different things. Evergreen trees can grow inside deciduous belts, and the reverse also happens. Learn the leaf habit of each common tree as a separate fact.
NCERT Concepts to Revise
- Tropical deciduous forest: The question asks which trees shed their leaves once a year in the dry season, which is the defining feature of this forest type.
- Tropical evergreen forest: Some trees in this question come from wet, layered forests where the canopy stays green all year.
- Moist deciduous forest: This 100–200 cm rainfall belt is where NCERT lists several of the species named in the question.
- Tropical semi-evergreen forest: Shows that evergreen and deciduous trees often grow mixed together, so a tree's region does not settle its leaf habit.