Tongass National Forest - Ecology

Ecology

Tongass includes parts of the Northern Pacific coastal forests and Pacific Coastal Mountain icefields and tundra ecoregions. Along with a region of the Central and North Coast regions of British Columbia designated by environmental groups as the Great Bear Rainforest, Tongass is part of the "perhumid rainforest zone," and the forest is primarily made up of western red cedar, sitka spruce, and western hemlock. Tongass is Earth's largest remaining temperate rainforest. The terrain underlying Tongass is divided between karst (limestone rock, well-drained soil, and many caves), and granite (poorly drained soil).

Unique and protected creatures seldom found anywhere else in North America inhabit the thousands of islands along the Alaska coast. Five species of salmon, brown and black bear, and Bald eagles abound throughout the forest. Many migratory birds spend summer months nesting among the archipelago, notably the Arctic tern.

Though its land area is huge, about 40% of the Tongass is composed of wetlands, snow, ice, rock, and non-forest vegetation, while the remaining 10 million acres (40,000 km2) are forested. About 5 million acres (20,000 km2) are considered “productive old-growth”, and 4,500,000 acres (18,000 km2) of those are preserved as wilderness areas.

Historically, logging operations tended to concentrate on lower elevation, bigger tree ecosystems for harvesting; at present, approximately 78% of the land remains intact, i.e. 383,000 acres (1,550 km2) out of 491,000 acres (1,990 km2) original big tree, low elevation forest area. Given the high value of these areas for wildlife species, close to 70% of this big-tree old growth forest is protected in reserves, and will never be eligible for harvest.

Of all of the big-tree old growth on the forest, including both low and higher elevation areas, no more than 11% of the remaining area will ever be harvested. Of the 5,700,000 acres (23,000 km2) “productive old-growth” on the Forest, 676,000 acres (2,740 km2), or 12% of the old-growth on the Forest, are slated for harvest over the next 10 years.