Temperate Forest

Temperate Forest, forests that make up around half the world's total forest, covering some 1,400 million hectares (14 million sq km, or 5.4 million sq mi). They occur mainly in Russia, North America, and Europe, with significant areas also found in Australia, New Zealand, Chile, Argentina, northern Asia, North Africa, and coastal South Africa. Many different temperate-forest types occur, including coniferous forests, and both deciduous and evergreen broadleaved forests. Biodiversity is generally less than in tropical forests, but varies greatly. Diversity in temperate rainforests can approach that of the tropics. Other common groups of species in temperate forests include oak (Quercus) and beech (Fagus). Temperate forests have long been used by humans for fuelwood, building materials, food and medicinal plants and shelter and are a common feature of many religions, myths, and folklore.

Following a history of deforestation stretching back to prehistoric times, global temperate forest area is currently stable and, through the processes of forest conservation and management, may even be increasing, unlike tropical forests. However, quantity is not necessarily matched with quality. Throughout the world, natural and semi-natural temperate forests (often called “old-growth” or “virgin” forests) are still being felled and replaced with natural new growth (through the process known as succession) or, increasingly, by tree plantations, designed specifically with future timber production use in mind. Whilst plantations produce timber, they provide few of the wider environmental and social goods and services derived from natural forests. For example, only a small proportion of wild plants and animals can live in plantations, which nowadays are often monocultures of non-native species. Loss of native forests is putting species at risk, such as the spotted owl (Strix occidentalis) in North America and the white-backed woodpecker (Dendrocopos leucotos) in Scandinavia.

In terms of natural forests, losses in the temperate regions have been even more dramatic than in tropical forests. In Western Europe and the United States, only about 1 per cent of the original forest remains, and the rest is either regrowth or plantation. When a forest is clearcut (that is, all of its trees are removed at once), the trees that regrow there may vary dramatically from the original. Currently, disputes about the future of old-growth forest are taking place in many areas, including the Pacific north-west of the United States; British Columbia, Alberta, and Ontario in Canada; and in northern Saamiland.

Temperate forests face several other threats. Air pollution and acid rain, from sulphur and nitrogen oxides, and ozone, has been linked with a marked decline in tree health in Europe, North America and parts of Asia. Research suggests that over the past few years almost a quarter of European trees have suffered defoliation of over 25 per cent. Pollution appears to be working with other factors, including climate, management methods, and pest and disease attack to create a decline, and sometimes death, of trees.

Fire is also a problem. In areas like the Mediterranean, human pressure is increasing the incidence of fire, through accident or vandalism, resulting in the destruction of fragile habitats. In parts of North America on the other hand, efforts to control forest fires have been so successful that the ecology of the forest is changing in areas that would naturally have a large number of fires.