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The light penetrates the rain forest only occasionally down to the ground. Under the dense treetops almost everything is shrouded in a light shade. In order to survive, the plants have to develop very special strategies to reach the desired sunlight. So many plants do not grow on the ground, but sit on the branches of the trees. Others are in the ground, but use the trees as a climbing frame to get up as quickly as possible.
Special living conditions in the tropical rainforest
On both sides of the equator, in the warm, always moist regions, the most important primeval forests of this earth extend: the tropical rainforests. Of the approximately 300,000 species of plants discovered to date, about two thirds are native to the tropical rainforest.
Depending on the altitude, in which the rainforest grows, one differentiates according to:
- Mangrove forests (near the coast)
- Lowland rainforests
- Mountain rainforests
- upper floor: scattered trees up to 60 meters high
- Crown region: Trees with a dense foliage roof, main canopy of the rainforest, up to about 40 meters in height
- middle floor: consists of young trees, tall shrubs, tree ferns, very rich in species
- Shrub layer: shrubs and young trees to about 5 meters
- Herb layer: the underlying regions receive only about 1-3% sunlight, here grow almost only ferns, fungi and mosses
Herb layer with mosses and ferns
Among the mosses and ferns, between 75 and 90% of all known species come from the tropical rainforests. Among the most impressive specimens are the tree ferns whose feathered leaves can reach up to four meters in length. About 3000-4000 species of mosses are native to the rainforest.
Examples of ferns:
- Streak ferns (Aspleniaceae) like the nest fern (Asplenium nidus)
- Tree ferns (Cyatheales, Dicksoniaceae)
- Potted Fishes (Polypodium, Lindsaeaceae)
- Bracken Family (Dennstaedtiaceae)
- Worm fern plants (Dryopteridaceae)
- Clover plants (Marsileaceae)
- Sword ferns (Nephrolepidaceae)
- Adderwort plants (Ophioglossaceae)
- Horsetails (Equisetaceae)
- Bracken herbs (Isoëtaceae)
- Bearberry Family (Lycopodiaceae)
- Moss ferns (Selaginellaceae)
Probably the best-known climbing plants are the lianas, which can lignify over time and grow up to 300 meters long. Creepers have a number of different ways in which plants cling to a tall tree. Rankers usually have corkscrew-like sprouts to hold on to. Spreader clippers fix themselves with spikes or thorns on the underground. Snappers have no trained climbing organs, the whole plant sprout winds around vertical climbing aids (trees and shrubs).
The Lianas include some species of the genera:
- Caper family (Capparaceae)
- Spindle-tree plants (Celastraceae)
- Trumpet Tree Family (Bignoniaceae)
- Bauhinia, Orchid trees (Bauhinia)
- Bottle Tree Family, Scaly Apple Family (Annonaceae)
- Soap Tree, Sumac Family (Anacardiaceae)
- Window leaf (Monstera deliciosa)
- some flamingo flowers (like Anthurium scandens)
- Efeutute (Epipremnum aureum)
- Tree Friend (Philodendron)
- Passiflora (Passifloraceae) such as the passion fruit or passion fruit
Plants that can not climb have come up with something different. They simply sit on the branches of trees to get to the coveted light. Frequently, the seeds of these epiphytes are brought by birds to the upper floors of the rainforest. In the course of evolution, these epiphytes have developed a variety of strategies to be independent of the water and nutrient supply of the soil.
The orchids include about 30,000 species, most of which are native to the tropical rainforest. Some species of orchids form freely suspended aerial roots, with which they can literally absorb the rainwater. However, orchids are not parasite plants that feed on the tree they live on. They just cling to the bark of the trees to get closer to the vital sunlight. Water and nutrients are mainly derived from the rain or fog that occurs here daily. Popular types:
- Real vanilla
Bromeliads are also growing on trees in the tropical rainforest.The funnel-shaped leaves collect rainwater and nutrients from particles that have been blown up. In the case of the pineapple plants, the leaves are covered with so-called suction scales. These scales swell as soon as they are wetted with rainwater. The plants provide habitat for microorganisms as well as frogs that lay their eggs in the reservoirs. Incidentally, the Tillandsien belong to the Bromeliaceae.
- Billbergia (oat grass)
- Tillandsia (Tillandsia)
4. Green lilies (Chlorophytum comosum)
5. dwarf pepper (Peperomia)
6. Shamflowers (Aeschynanthus)
In addition to the actual epiphytes that spend their entire lives on a larger plant, there are also some specialized plants that only spend up to (or from) a certain age there. These include, for example, two known plants:
1. strangler fig
The life of a strangler fig starts as a seed on a branch of a big tree. First, it grows there as a simple Aufsitzerpflanze. If a strangler fig grows and grows well, it is almost always associated with the death of its host tree. As soon as the strangler fig has formed its own stilt root, it begins to strangle its host. The strangler figs include various species of the genus Ficus.
Some representatives of the genus Monstera (Fensterblatt) germinate on the ground and go first to the search for a larger tree. Only there do the right leaves emerge. When climbing, Monstera forms two different root types: the anchoring roots and long, very fast-growing aerial roots. With them it is possible for the plant to reach the ground even from over 30 meters and to absorb nutrients and water there, even if the lower part of the plant is already dead.
Other plants do not even try to survive on their own. They feed on other plants.
- Rafflesia (Rafflesia)
- Corynaea crassa (from the Balanophoraceae family)
In the tropical rainforest, the light on the ground is much lower than in our deciduous forests. As a result, there is a lower diversity of herbaceous soil growth. Many of these plants are popular as indoor plants because of their low light requirements:
- Arum family (Araceae) such as the leaf (Spathiphyllum), piston thread (Aglaonema)
- Flamingo flowers (Anthurium)
- Dieffenbachie (Dieffenbachia)
- Parsley Family (Marantaceae) as the Basket Marant (Calathea Zebrina)
- Sauerkleegewächse as Biophytum sensitivum
- Arrow leaves (Alocasia)
- Radiation artery (Schefflera), sometimes also climbing plants
- Raublattgewächse, Borage Family (Boraginaceae)
- Swan flower (Butomaceae)
- God's Eyes (Tradescantia) like the Zebra-nettlewort (Tradescantia zebrina)
- Dwarf pepper (Peperomia) such as Peperomia caperata
- Silver Net Sheet (Fittonia)
In addition, different palms and bamboo species (such as the giant bamboo) are among the typical representatives of the tropical rainforest. But plant species that are planted in Central European gardens, are found in the rainforest like boxwood plants (Buxaceae). Today, more than 200 palm species with about 2500 subspecies are known. Most palm trees are at home in the tropical rainforests, because they need a lot of heat and moisture, but also a bit more light than other plants that occur there. That is why they are mostly found on glades or on the edge of the rainforest. Palm trees with low light requirement:
- Mountain palm (Chamaedorea elegans)
- Great ray palm (Licuala grandis)
- Kentia palm (Howea fostweriana)
- Australian umbrella palm (Livistona australis)
A very special plant species, which occurs in the tropical rainforest, are the carnivorous plants. These include, for example:
- Pitcher plants (Nepenthes)
- Tubular plants (Sarracenia) such as Sarracenia purpurea
Many plants that we know as spices or fruits, or whose wood is made into furniture, come from the tropical rainforest. Just to name a few examples:
- Banana (growing on glades)
- Papaya (Carica papaya)
- Real vanilla
The tropical rainforest has an incredible biodiversity. The individual plants have become extremely specialized because of the unfavorable soil and site conditions. Often the plants occur within a radius of several hundred meters only once, large accumulations of the same kind are very rare. Some plants are very shadow-tolerant, others form beautiful flowers and are therefore popular as indoor plants. They all like it warm and humid all year round.