RAINFORESTS

RAINFORESTS

Characteristics
1. Thick, luxuriant, broadleaved, evergreen forests
2. areas of high rainfall (1500-2500mm annually)and high temperature (above 26deg C)
3. Equatorial climate- between latitudes 20 deg N to 20 deg S
4. Diversity of plant species
  1. Hot and wet environment - large range of animal and plant species.
    1. fruits eg. bananas, mangoes Spices eg pepper, cinnamon Vegetables eg corn, pandan, Nuts eg Brazil nuts, walnuts
5. Structure
  1. 1. Emergent layer (above 30m) 2. Canopy layer (20-30m) 3. Undergrowth layer (below 20m)
    1. EMERGENT - Uppermost layer - tallest trees (upto 80m) - tall, straight, smooth trunks with few branches
    2. CANOPY - trees close together - trees between 20-30m - crowns interlock to form continuous cover - Lianas (thick woody vines twine up trees) - Epiphytes (plants growing on trees eg. ferns, orchids, mosses, lichens)
    3. UNDERGROWTH - sparse vegetation & poorly developed as very little sunlight - some lianas and epiphytes and small plants that are thin and widely-spaced -larger leaves -thin layer of leaf litter
6. Adaptation of plants
  1. BARK & BRANCHES
    1. tall straight trunks- to get maximum sunlight - Smooth bark - rainwater flows from crown to roots
  2. LEAVES
    1. broad- to capture sunlight
    2. waxy, leathery, hairy surface - minimises moisture loss thru transpiration due to high temp
    3. drip tips- allow water runoff & prevent fungi/bacteria growth
  3. FRUITS/FLOWERS
    1. air is still / no wind for dispersal/polllination
    2. colourful/strong smelling to attract pollinators
  4. ROOTS
    1. Buttress- 1-5 m above ground- to support heavy weight of tall trees
    2. Shallow- nutrients found in top layer of soil (rapid decomposition of fallen leaves/branches)- water available throughout the year

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	Criado por sangitapillai mais de 10 anos atrás