Forests have many and varied functions. Not only do they provide food and fuel, they are also increasingly critical in the preservation of national lands, the conservation of water resources, and human health, culture and education. In addition to being home to living creatures, they contribute to maintain biodiversity and play an important role in the regulation of the climate. When we compare forest with non-forest areas within a single region, we find that forest areas are generally higher in humidity and milder in temperature.

The presence of forest prevents soil run-off and erosion, maintains the fertility of the soil and mitigates sudden freshets that lead to flooding. Water released from forest areas enters the sea and nurtures a wide variety of life forms too. Forests themselves are giant sinks of carbon: they are absorbing and assimilating carbon dioxide, which accounts for the majority of the greenhouse gases that are now accelerating global warming.