About UNEP UNEP Offices News Centre Publications Events Awards Milestones UNEP Store
UNEP Website GEO Home Page

Old growth forests

Old growth forests, which are characterized by stands of large and old trees, a distinct species composition, a multilayered canopy, and a large build up of organic matter (Lund 2000), have many positive attributes. They are a source of high-value timber, contain large amounts of carbon, harbour a large reservoir of genetic diversity, provide habitat for many species, regulate hydrological regimes, protect soils and conserve nutrients, and have substantial recreational and aesthetic value (Marchak, Aycock and Herbert 1999). Much of the interest in old growth forests stems from the powerful images which they project of rich biodiversity and timeless stability. Visitors often sense a form of spirituality and grandeur in such forests and most people place a high value on them.

Old growth forests once occurred in all North American ecosystems although it is now difficult to determine their exact extent. Remnant old growth forests and stands still remain, especially in the Pacific Northwest and down the Pacific coast to California. The classic old growth forest in this area contains redwoods, cedars, Douglas fir, hemlock and spruce. The region probably still contains about half the world's remaining unlogged coastal temperate rainforest, with the greatest share in British Columbia.

Decline of old growth forest (percentage of total)

Old growth forests have declined rapidly since the middle of the 20th century

Source: H. John Heinz III Center 2001

The majority of old growth lost in the eastern and lower elevations of North America was due to conversion of land to agriculture and urban environments. In the west (see bar chart) and mountainous regions, loss has been due to harvesting of timber and conversion to younger more vigorously growing stands along with recent catastrophic events such as the eruption of Mount St Helens and the Yellowstone fires (Harmon 1993, H. John Heinz III Center 2001).

The decline in old growth forest was largely driven by increasing worldwide demand for timber and high prices in the 1970s (Mathews and Hammond 1999). In recent years, losses due to timber harvesting have slowed because of increasing environmental concerns including the desire to preserve natural forests and to prevent further destruction of critical wildlife habitat and biological diversity.

Natural forests are still deemed by some to be essential to Canada's industrial timber supply. Canada harvests about 175 million m3 of timber annually (NRC 2000) from approximately 1 million ha, or 0.5 per cent of the nation's commercial forest base. There is little mature second growth forest and so logging continues mainly from mature natural forests.

The paradigm shift towards the ecosystem approach to managing North America's old growth forests reflects the combined power of scientific knowledge, the action of voluntary groups, public awareness, market pressures on industry, and governmental response (see box).

Clayoquot Sound

Clayoquot Sound, a 1 000 km2 wilderness on Vancouver Island, became the focus of a well publicized debate over old growth logging. Beginning in 1984, environmentalists and the Nuu-chah-nulth First Nation protested against clearcutting by blocking logging roads, among other tactics. During 1989-93, government task forces attempted to resolve the conflict and large tracts of coastal temperate rainforest were set aside for protection (MSRM 2002). Claiming that logging was still permitted on 70 per cent of the Sound, the protesters continued their actions, and brought national and international attention to the issue.

In 1995, in recognition that the Nuu-chah-nulth had not been adequately consulted, public negotiations began on a settlement with the First Nation peoples. Recommendations were formulated and adopted by the provincial government (May 1998). A 4 000 km2 model forest was also established.

Progress was subsequently made in resolving the remaining conflicts. One of Canada's largest forest products companies announced in 1998 that it would phase out clear-cutting in British Columbia and design a new strategy focusing on old growth conservation (MacMillan 1998). An agreement was struck between First Nations and environmentalists to set aside most of the western coast of Clayoquot Sound and to promote economic development through small-scale logging, non-timber forest products and ecotourism. With the January 2000 designation of Clayoquot Sound as a UNESCO Biosphere Reserve, industry, environmentalists, governments and First Nations established a new form of governance based on shared responsibility for the ecosystem (ENS 1999, Clayoquot Biosphere Trust 2000).