#1: Sparse Undergrowth• There is sparse undergrowth in the forest floorof the tropical rainforest.• This is because very little sunlight (about onepercent) passes through the canopy andreaches the forest floor.
#2: Large Variety• There is a large variety of plants in the tropicalrainforest. It is estimated that rainforests maycontain more than 750 species of trees and1500 species of other plants.• This is because of consistent high temperatureand rainfall throughout the year that promotesplant growth.
#3: Extreme density• Tropical rainforests are extremely dense due tothe presence of a large variety of plant specieswhich can grow in the tropical rainforest.
#4: Evergreen Leaves• Tropical rainforests have evergreen leaves dueto the consistently high rainfall throughout theyear.
#5: Large & broadleaves• Tropical rainforests have large and broadleaves to maximise the surface area forphotosynthesis.
#6: Thin & smooth barks• Tropical rainforests have developed thin andsmooth barks because there is no need forprotection against cold or dry conditions.
#7: Buttress Roots• Some trees in the tropical rainforest havebuttress roots, which are thick and spread outwidely to support the great weight of trees.
#1: Low Light• The canopy layer prevents sunlight fromreaching the lower layers of the tropicalrainforests.• Some plants such as the epiphytes and lianashave adapted to this low light condition bygrowing on tree branches.• Furthermore, these trees have branchesonly on the top one-third portion of thetrunks to get maximum sunlight.
#2: Bacteria Growth• High temperature and high rainfall in thetropical regions promote rapid growth ofbacteria.• Hence, tropical rainforest have waxy leaveswith drip tips to allow rainwater to drain offeasily.• This prevents harmful bacteria from growingand protects the plants from diseases.
#3: Still air below canopy• The presence of the continuous canopy resultsin still air in the layers below it and this does notallow pollination to be carried out by wind.• Hence, flowers and fruits in the tropicalrainforest are colourful and sweet-smelling.• This attracts insects for pollination and animalsfor seed dispersal.
#4: Rapid humus formation• High temperatures and rainfall all year roundcauses the leaf litter to decompose and formhumus rapidly.• This supplies nutrients to the topsoil, which isthe uppermost layer of the soil.• Hence, the roots of trees in the tropicalrainforest are shallow and spread widelyto absorb the nutrients present in the topsoil.
EPIPHYTES• This refers to plants that grown on and usetrees for physical support.• Rainwater and decaying leaves provide theepiphytes with water and nutrients.• Example: Bird’s Nest Fern, Orchids
LIANAS• Refers to thick, woody vines that wind aroundtree trunks to reach for sunlight
PARASITIC PLANTS• This refers to plants that compete with the hosttree for space, sunlight and nutrients.• These plants are common in the canopy andunderstorey layer of the rainforest.• Example: Strangling Fig