2. Condition for Growth & Adaptation
Why are tropical rainforests and mangroves located in the tropics?
Conditions for the growth of tropical rainforests
· High annual rainfall
· High mean annual temperature
Click on Layers and check out the areas with tropical rainforest, temperatures and rainfall in the drop-down menu. (no need to sign in - just click cancel).
What are the rainfall and temperatures experienced by the areas which tropical rainforests are found?
Conditions for the growth of mangroves
· Warm waters with temperatures above 20 degree Celsius
· Sheltered environment e.g. along or very close to the coast, such as shallow river mouths or behind islands.
Calm water condition so that the seedlings are able to take root and grow without getting washed away by strong waves.
Calm water conditions encourage the accumulation of fine sediments containing nutrients, which mangrove plants require to sustain their growth
Adaptations of tropical rainforests to the tropical climate
Leaves (i.e., broad, waxy and drip tips)
Broad to maximise absorption of sunlight
waxy to reduce loss of water through transpiration
Drip tips to allow rainwater to flow off easily so that fungi or bacteria will not grow on it.
· Roots (i.e., buttress) - as tall as 5 metres above ground surface
Thick buttress root to keep the tall trees upright and prevent them from toppling.
Shallow buttress root as most of the nutrients are found on the top layer of rainforest soil
Adaptations of mangroves to coastal environments
· Leaves (i.e., salt-secreting)
Avicennia have salt-secreting leaves that can remove salt from the saline water which their roots have absorbed.
Sonneratia deposit excess salt in older leaves which they eventually shed.
· Roots (i.e., pencil, cone, prop, and knee-bend; salt-excluding)
Aerial roots can help the trees take in oxygen directly from the air when they are exposed during low tide as the soil is poor in oxygen.
The dense roots of the Rhizophora help to anchor the mangrove plants to the soft soil and prevent them from being uprooted and washed away by strong waves
Bruguiera have salt-excluding roots which can prevent salt from entering the plant.
Pencil like aerial roots (Avicennia) of the Mangrove in Sugei Buloh. Photograph taken at Sungei Buloh, Singapore 2008
More photos which I took of Mangroves in Singapore, Malaysia, Brunei and Thailand @
Read here on the rich ecosystem of our built timah nature reserve
http://tidechaser.blogspot.sg/2008/04/bukit-timah-nature-reserve.html?m=1
Watch the video below on the conservation of Built Timah Nature Reserve
360 virtual learning journey @Sungei Buloh
Revealing our Roots: Trees of Singapore | Virtual Tour of Primary and Secondary Forests