Taiga

The inhospitable conditions of the boreal zone have meant that until recently mineral resources have not been fully developed. Mining usually involves clear-felling of large areas of forest; however, the impacts can go beyond the site of mining activity. Once operations commence, environmental impacts arise from the disposal of acidic effluent from tailings, the silting of rivers, and pollution from processing plants.

Recently some very large schemes have been created, flooding vast areas of land. They have disrupted natural drainage and rivers and dramatically altered the landscape. The traditional lands of the indigenous peoples, which are valuable for hunting and fishing, have also been damaged. Much opposition to the schemes is based on the fact that they disturb the natural environment for local people but mainly benefit those from outside the region.

The boreal forests are a major global store of carbon and so play an important role in regulating the Earth’s climate (see Carbon Cycle (ecology)). Recent research suggests that currently the forests are not taking up as much carbon as they did prior to the mid-1970s. If this is the case, then the net transfer of carbon into the atmosphere will have contributed to the trend of increasing atmospheric carbon dioxide (CO₂) levels and the greenhouse effect. Several factors seem to be responsible for the net loss of carbon from the biome.

The impact of logging and clearance of these forests for other uses could be a factor, together with more widespread disturbance of these forests by fires, insect outbreaks, storms, and damage due to acid precipitation. However, it is also thought that forest decline may have been brought about through global warming itself. Higher temperatures may, for example, reduce the natural rates of recovery of these forests following disturbance, so that forest die-back can occur. Even if the clear-cut forest areas are converted to plantations, a net transfer of carbon to the atmosphere results, because old growth forests tend to support more biomass than commercial ones.

If global warming does disrupt the boreal forests, and results in significant net transfers of carbon into the atmosphere, then a dangerous positive feedback loop could be established. The carbon released would increase the rates of global warming and further increase the rate of decline of the forests themselves. Although it is possible that the biome could expand into the tundra, such northward migration would be slow and unlikely to compensate for the decline in the forests in the south. The further loss of boreal forest could therefore have a major impact on global climate.

Given the problems now facing the taiga, the need to develop strategies for managing these areas in a more sustainable way has become a focus of current concern. At the global scale, the fate of the forests depends on attempts by the international community to control CO₂ emissions and slow the rate of climate change. At national, regional, and local scales, more sustainable ways of using the resources in the biome must be found. These include afforestation programmes, which produce more natural forms of plantation, integrated forms of ecosystem management, and the development of forestry based on selective felling, rather than clear-cut felling. The conservation of old growth forest and the biodiversity resources of the taiga are also high priorities.