Tropical rainforests are home to more than two-thirds of the world's plant species. Plants are a source of food for rainforest animals, as well as shelter. As a result of the humid, tropical rainforest environment, plants must adapt in order to survive. They also adapt in temperate forests, though not as drastically.
Tropical rainforests are dense, which is why leaves have adapted to try to capture as much light as possible. Leaves in the dark understory of the rainforest are large so they can absorb as much light as possible. Some leaves are able to turn as the sun moves. The amount of water a plant catches is also controlled by leaf adaptations. Some leaves have drip tips and a waxy surface to allow water to run off. This stops the growth of bacteria and fungi. Many bromeliads and epiphytes have a central reservoir to collect water, instead of collecting it in roots. This way the water is quickly absorbed through hairs on leaves.
Plant roots have also adapted to the habitat. The forest's soil is poor in nutrients, with the top level the most nutritious for plants. Some plants have shallow roots to help absorb the nutrients at the top soil level. Some areas of the tropical rainforest have shallow soil, so roots have adapted to grow partially above ground to help support the plant.
Plants face a battle to reach sunlight. Along with making adaptations, plants grow in certain places in order to absorb as much sunlight as possible. Some plants grow or climb on top of one another to reach sunlight. The epiphytic orchid has aerial roots that cling to a host plant; it absorbs the host plant's minerals and draws water from the atmosphere.
Feeding on animal matter is another example of a plant's adaptation to the tropical rainforest. The pitcher plant Nepenthes rafflesiana, which is native to southeast Asia, is an example of a carnivorous plant. It gets nutrients from insects. It may also eat small mammals and reptiles that try to steal insects from inside its pitcher.
Temperate Rainforest Adaptations
The temperate rainforest has fewer plant variations than in tropical rainforests. This is because there is less of a seasonal fluctuation; there are cool summers and mild winters. The environment is damp from coastal fogs and rainfall, with few nutrients in the soil. Tall trees are the dominant species. Therefore, epiphytes, such as ferns and mosses, grow onto of other plants to find light. Seedlings grow on decomposing fallen logs to get their nutrients, since the forest's soil is poor.