Biological Adaptation

These adaptations depend on the geology and basic fertility of the region and some of the mechanisms that are especially well developed in tropical rain forests are:

• Root mats consisting of many fine feeder roots which penetrate the surface of the litter and quickly recover nutrients from leaf fall and rain before they are leached away. Root mats also inhibit the activity of denitrifying bacteria, thus preventing loss of nitrogen.
• Mycorrhizal fungi associated with root systems act as nutrient traps and help in the recovery and retention-of nutrients. This symbiosis is also present in temperate forests of areas that are basically poor in nutrients.
• Evergreen leaves have thick waxy cuticles that retard loss of water and nutrients, also leaves have pointed tips or 'drip tips' that drain off water fast, thereby reducing leaching of leaf nutrients.
• Algae and lichens that cover surfaces of many leaves pick up nutrients from rainfall some of which becomes available to the leaves immediately. Lichens also fix nitrogen.
• Thick bark inhibits diffusion of nutrients out from the phloem and subsequent loss by stem flow i.e., rain running down the trunks of trees.