Relatively untouched by human activity and allowed to attain immense size and age, old-growth forests are environments that exhibit unique properties in a number of dimensions. When allowed to flourish, they can help mitigate some of the environmental consequences of industry and society in ways that a younger forest cannot always match. Unfortunately, these areas are scarce, and often in just as much danger of being stripped for development as younger forests are.

​

Areas with good biodiversity can produce a number of important benefits for their regions and, by extension, the people who live nearby. These include functions like protecting nearby water systems, encouraging the formation of healthy soil, and breaking down ambient air pollution.

​

Untouched old-growth forests exhibit a number of important properties that younger, disturbed forests may not. An old-growth forest may have more fallen and decaying trees, for example, as well as trees with more established root structures and a higher average height. All of these help shape the local environment, providing a greater variety of habitats, greater access to some important nutrients, greater soil drainage and aeration, and other benefits. These can, in turn, promote the survival of a wider range of organisms in the area.