The tropical rainforest or equatorial rainforest has four well defined layers:
– The emergent layer – These consist of trees 35-45 meters high. They have tall, straight trunks and a wide spreading crown. There are little to no branches below the crown. There is a lot of sunlight here, high wind speeds and little moisture.
– The canopy layer – This consists of trees about 20-34 meters high. They have rounded crowns that are packed closely together to form a continuous cover. It is mote sheltered than the emergent layer. More moisture is available in this layer than in the emergent layer. Many mammals and birds live in this layer.
– The lower storey trees – These are 10- 19 meters high and the crowns are tightly packed together. There is very little light at this layer since most of it is filtered out in the canopy and emergent layers. The air has a very high humidity here. Birds and mammals are very common in this layer.
– The shrub layer – There is very little light here. The air is very humid and temperatures are high and steady. There is a lot of moisture here but because there is very little light, photosynthesis is very limited. This is why there is very little undergrowth in the forest.
– The forest floor – Very few plants manage to survive here. Mostly saprophytes (plants that get their food with the help of root fungi) .grow here. Some mammals such as tapirs and deer live here. Their diet consists of fallen fruits and seeds. There is not a lot of organic matter on the forest floor as nutrients are recycled quickly.
Some characteristics of the trees found in the rainforest are:
1. The trees are evergreen. There is no season in which most of the trees shed their leaves. At anytime of the year some trees many be producing fruits while others are producing flowers.
2. The trees have tall, straight trunks with no leaves or branches for most of its length because these leaves would be useless for photosynthesis because it is very shady below the crown.
3. As said in the previous line, they have a crown, which is well defined. All leaf growth is concentrated here.
4. The leaves are dark green and leathers which helps to protect them from intense sunlight.
5. Most of the leaves have a drip tip which helps them to dry off quickly after heavy rainfall. A dry leaf transpires and photosynthesises more efficiently.
