9.3.2. Terrestrial Ecosystems

9.3.2.1. Forests

Although significant land clearance has been a feature of many small island states over decades of settlement, extensive areas of some islands still are covered by forests and other woodlands. For instance, forest and woodland cover in the Solomon Islands, Vanuatu, Dominica, and Fiji is more than 60% of the total land area (see Table 9-2 and Annex D, Table D-7).

Although the tropical forests on small islands are not as critical to the global carbon budget as the tropical rainforests of the South American and African continents, their influence on local and regional climates is no less important (IPCC 1996, WG II, Box 1-5). Forests also are of great socioeconomic importance as sources of timber, fuel, and many nonwood products. Furthermore, forests provide a broad range of other economic and social goods, even though their true value may be difficult to quantify. For example, they provide a basis for ecotourism, habitats for wildlife, and reservoirs for conservation of biological diversity; they also reduce soil erosion. Moreover, forests are of spiritual importance to many indigenous peoples (IPCC 1996, WG II, Section 1.1), many of whom inhabit small islands.

It is possible that tropical forests will be affected more by anthropogenic forces than by climate change per se, as long as deforestation continues at its current rate (IPCC 1996, WG II, Box 1-5). Tropical forests are likely to be affected more by changes in soil water availability (caused by the combined effects of changes in temperature and rainfall) than by changes in temperature alone. Forests are particularly vulnerable to extremes of water availability (drought or flooding) and will decline rapidly if conditions move toward one of these extremes. Increasing temperature and extreme events also may increase the incidence of pests and pathogens, as well as the frequency and intensity of fires.

On the other hand, increasing amounts of CO₂ may enable some forest species to use water and nutrients more efficiently (IPCC 1996, WG II, Section 1.3.7). CO₂ fertilization may have the greatest effect in the tropics, where it may lead to a gain in net carbon storage in undisturbed forests, especially in the absence of nutrient limitations (IPCC 1996, WG II, Section 1.4.3).

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