Most of the trees of the tropical rainforest's canopy have leaves that are smooth and shiny on both sides, similar to those in the laurel family.
The different trees of the tropical rainforest have leaves that look very similar to one other. In contrast, the leaves of temperate woodland trees come in many different sizes and shapes.
The leaves of many rainforest species are of similar size and taper to a point, known as the drip-tip.
It is believed that this shape allows the leaf to shed water quickly, preventing tiny lichens, algae and mosses (epiphylls) from growing on the moist leaf surfaces and eventually covering them and shading the photosynthetic cells with their own.
This theory is supported by two observations. Plants in the damper understory have more uniform leaves and longer drip-tips, and leaf points tend to be longer in the wettest forests.
The leaves of emergent tree species, which occupy a less humid environment, are much more varied in form, and often have little in the way of a drip-tip. They are also often smaller and thicker than leaves of trees at lower levels.
Many trees, especially in the drier forests, are deciduous - they lose their leaves each year. The leafless period frequently lasts a month or less, and some species exhibit leaf replacement, shedding the old leaves and growing a new set simultaneously.
The intervals between leaf sheddings are usually regular, but often do not coincide with a calendar year.
Terminalia catappa changes its leaves every six months, in its native Malaysia and in West Africa, where it has been introduced.
A Koompassia tree in Malaysia replaced its leaves every 12.7 months over a period of several years
Evergreen trees in a tropical environment do not continuously produce new leaves. Instead, leaves are produced in flushes of new growth.
All the shoots suddenly grow and make several new leaves at once, waiting for many months before repeating the process.
New leaves appear quickly, and are likely to be brightly hued, soft and floppy.
One explanation for this pattern of leaf replacement is that it helps the leaves to avoid being eaten. If leaves grew all the time, leaf-eating creatures that preferred new, soft leaves would always have food.
Thus, their numbers would increase and they would damage most of the succulent young leaves.
A big flush of leaves after a long interval satiates the few leaf-eaters that have survived on the old leaves, and allows most of the new leaves to expand unscathed.
Just as leaves are produced at long intervals, so are flowers, possibly for the same reasons.
By flowering and fruiting at the same time, the trees ensure that not all of the seeds needed to produce the next generation will be eaten.