FROM RAINFORESTS AND TEMPERATE DECIDUOUS FORESTS
(Can you match the product with the plant?
Every forest has structure vertically and horizontally. Plants growing together in a particular location are there because they share certain needs, the most important being sunlight and water.
Temperate deciduous forests undergo four seasons every year: summer, autumn, winter and spring. In the autumn the trees lose their leaves. This opens the forest floor to the sunlight, so a temperate deciduous forest turns green every spring from the forest floor up, starting with the wildflowers, followed by the understory shrubs and small trees. The last plants to leaf out are the canopy trees. Canopy trees then close the forest floor to sunlight. In autumn all the deciduous plants lose their leaves, starting the seasonal cycle again.
Tropical rainforests occur near the equator where it is hot and humid. Daylength is constant, so the four seasons of a temperate deciduous forest do not occur here. There is no seasonal leaf drop in the rainforest as in a temperate deciduous forest; the canopy stays closed. A closed canopy lets less than 1% of the sunlight reach the forest floor. This is a problem for plants that need sunlight.
The solution? If the sun cannot shine down on the plants, then the plants must go up to the sun, and they do this in a series of layers. This is what defines the basic structure of a forest. In the rainforest each layer harvests sunlight while trapping humidity below. The series of layers are series of microclimates or conditions driven by the need for sun and water.
Some plants will grow up tall, like the canopy trees of a temperate deciduous forest. The tallest trees are called emergents. They stand over the upper and lower canopy trees, which stand over the shrub layer. There are also plants that hitch a ride to the sunlight. These are vines, and in the rainforest vines are called lianas. Up to 90% of the world’s vines grow in rainforests. Another strategy can be seen in the epiphytes, or air plants. These plants can live on top of other plants. They don’t need soil themselves, but they can help to create another layer of soil up in the canopy, a peculiarity of the rainforest.
In the following activity, see if you can match the forest product with the plant, then find out which part of the forest's structure this plant belongs to: