Biological Diversity Ecosystem Condition and Productivity Soil and Water Role in Global Ecological Cycles Economic and Social Benefits Society's Responsibility
Carbon Cycle
Role in Global Ecological Cycles
4.1 Carbon Cycle References
Forests occupy roughly one third of the earth's land surface, and Canada has approximately 10% of the earth's forests. Because of their size, forests play a major role in the functioning of the biosphere. Global ecological cycles are a complex of self-regulating processes responsible for recycling the earth's limited supplies of water, carbon, nitrogen, and other life-sustaining elements. The world's forests are critically dependent on, and make substantial contributions to, these global processes.

The indicators for this criterion deal with the role of forests and the forest sector in the global carbon cycle. Forest management can have substantial impacts on the role of forests in the carbon cycle. The impact of forest management on the global hydrological cycle is also important, but related indicators are found under Criterion 3.

Increasing atmospheric concentrations of carbon dioxide are one of the principal factors linked to global warming observed over the past 50 years. Element 4.1(Carbon Cycle) examines the role of forests as sinks or sources of atmospheric carbon and describes the impact of disturbances such as insects, fire, and harvesting on carbon movement among the atmosphere, forests, and forest products. Carbon budgets that estimate the balance between carbon storage and carbon release from forests and forest products indicate the contribution of the nationís forests to atmospheric CO2 enrichment. Forest industries consume a large amount of energy in harvesting, transporting, and converting timber into products. This element also discusses the types of fuel used by the forest sector, and their impact on the global carbon budget. Efforts by the sector to improve energy efficiency through the introduction of cleaner-burning fuels are also discussed.