Environmental functions of forests and trees

Due to a high ratio of coastline to land area in Small Island Developing States (SIDS) and relatively short distances between the uplands and the coastal areas, the following environmental functions of forests and trees are of special importance, and in many cases outweigh their production value:

  • Soil and water conservation: The relatively limited size of watersheds makes soil and water conservation a priority in SIDS. The soil improvement role of these trees is also important to the success of plant growth in coral-based soils, which are among the least fertile in the world.

  • Coastal protection: Coastal forests act as buffers against cyclones, strong winds and storm surges, which are common in many tropical islands.

  • Conservation of biological diversity: Small islands generally have lower plant and animal species diversity, but a higher percentage of endemism than continental masses.1 Many of these endemic plant and animal species are found in forests. The small size of individual plant and animal populations renders them more susceptible to extinction brought on by deforestation, unsustainable forestry and agricultural practices, unmanaged tourism and the introduction of exotic species. The conservation of biological diversity - both directly (in the forest) and indirectly (by protecting associated ecosystems such as coral reefs) - is therefore one of the most important environmental roles played by forests in small islands.

  • Links with marine ecosystem: Coastal forests such as mangroves and tidal forests produce leaf litter and detrital matter, which enter the marine food web. Mangroves serve as feeding, breeding and nursery grounds for numerous commercial fish and shellfish - including most commercial tropical shrimps. In addition, mangrove forests act as a sediment trap for upland runoff, thereby reducing water turbidity and protecting sea grass beds, nearshore coral reefs and shipping lanes from siltation.

Notes

1 In Mauritius, the Dominican Republic, Haiti, Jamaica and Fiji, more than 30 percent of the higher plant species are reported as endemic. An estimated 24 percent of the total number of bird species are endemic in Solomon Islands and 20 percent in Fiji. States with a high percentage of endemic mammals include Mauritius (50 percent), Solomon Islands (36 percent) and Fiji (25 percent).

last updated:  Friday, October 28, 2005