Tropical Rain Forest Summary Sheet
1. location there are four main areas or tropical rain forest
(i) Central America
(ii) Amazon Basin
(iii) Zaire Basin
(iv) Indonesia
2. climate hot + wet all year round
(there may be a wetter season, see the graph below)
3. vegetation
The Tropical Rainforest is an environment which is hot and
wet all year round. The natural forest is a thick mat of trees
which grow rapidly upwards in search of essential sunlight. The
forest can be divided into vertical zones. :-
emergents These are individual
trees (e.g. capoc) which break above the canopy to heights of
65 - 80 metres.
canopy
This might reach 45 metres above the ground and would
be seen from the air as a solid mass of tree tops. These trees
tend to be hardwoods (e.g. ebony; mahogany; rosewood; teak).
There are over 500 species and as many as 250 different ones
can colonise a small area of land. Tree trunks are straight and
branchless in their lower parts in an effort to grow tall. As
with the emergents, these tall trees need strong support at their
base and tend to have buttress roots. The leaves have drip tips
to easily shed the heavy rainfall. Lianas are vine - like plants
which use large trees as a climbing frame to reach the canopy.
forest floor This zone is
dark and damp. There is little undergrowth because the sunlight
cannot reach the ground level. Fallen leaves, branches and trees
soon rot in the hot wet climate.
clearings and river banks
Dense undergrowth develops in these areas where sunlight can
penetrate.
4. peoples' use of the environment
Uses of the rainforest include:-
i. logging the valuable timber resources
ii. mining the valuable minerals
which lie beneath this largely unexploited area e.g. oil and
metallic ores
iii. farming :-a. by native inhabitants
i.e. 'slash + burn' cultivation
b. by migrants from the overcrowded towns. These people tend
to clear and cultivate small plots of land beside the lumber
roads. Their impact is large as they arrive in their thousands.
c. by large cattle ranches. These clear thousands of hectares
using bulldozers or firebombs and plant the land in grass.
iv. increasing discovery of medicinal uses
of many plants in the forest.
5. peoples' abuse of the environment
If the forest is damaged, e.g. by fire, it can naturally regenerate
but where people destroy thousands of hectares and attempt to
farm this land a number of problems may occur which leave the
land of little use. Soil erosion, with the heavy rain, can strip
the bare land of its essential soil or the hot sun can bake the
land as hard as concrete.
The rainforest is essential as a home for insects + plants (50%
+ of the planets plants + animal species live here). Many of
the plants are valuable sources of medicines + drugs (many yet
undiscovered). It also provides us with a valuable source of
oxygen, without which CO2 would increase with resultant global
warming. It is also the home of native people whose lives and
lifestyles are being destroyed.
