Introduction
The Tongass National Forest stretches across 68,000 square kilometers of southeast Alaska's Alexander Archipelago and adjacent mainland coast, making it the largest national forest in the United States. It is the largest intact temperate rainforest in North America and one of the last great old-growth forest ecosystems on Earth.
The Tongass is a landscape of towering Sitka spruce and western red cedar, glacier-carved fjords, and thousands of islands woven together by a web of wild salmon streams. Its ecological productivity rivals that of tropical forests, driven by the extraordinary relationship between Pacific salmon, bears, and old-growth trees.
Geography & Extent
- Area: 68,000 km² (26,250 sq mi)
- Location: Southeast Alaska, USA
- Islands: Over 1,000 islands in the Alexander Archipelago
- Coastline: ~18,000 km
The Tongass encompasses most of Alaska's panhandle, stretching roughly 800 kilometers from Yakutat in the north to Ketchikan in the south. It includes more than 1,000 islands of the Alexander Archipelago, separated by deep fjords and narrow straits. The coastline is extraordinarily complex, totaling roughly 18,000 kilometers.
The forest ranges from sea level to glaciated mountain peaks exceeding 3,000 meters. Massive icefields, including the Juneau Icefield and the Stikine Icefield, feed tidewater glaciers that calve icebergs directly into the ocean. These glaciers have carved the deep U-shaped valleys and fjords that define the landscape.
Climate & Hydrology
- Annual Rainfall: 1,500-5,000 mm
- Average Temperature: 1-12°C (varies seasonally)
- Snowfall: Heavy at higher elevations
The Tongass has a maritime climate moderated by the warm Alaska Current, which keeps temperatures relatively mild for its latitude. Winters are cool but not extremely cold at sea level, while summers are cool and damp. Rainfall varies dramatically, from 1,500 millimeters in drier areas to over 5,000 millimeters on exposed western slopes.
The forest's hydrology is dominated by thousands of salmon streams that connect the mountains to the sea. These streams carry glacial meltwater, rain, and critically, the nutrients from spawning salmon back into the forest. This salmon-forest cycle is the ecological engine that drives the Tongass ecosystem.
Biodiversity
- Salmon Species: 5 Pacific species
- Brown Bear Population: ~5,000
- Bald Eagles: ~10,000 nesting pairs
- Old-Growth Trees: Up to 800+ years old
The Tongass supports all five species of Pacific salmon — king, sockeye, coho, pink, and chum — which return in millions each year to spawn in the forest's streams. Bears, eagles, and dozens of other species depend on this annual salmon run. When bears carry salmon carcasses into the forest, the marine-derived nitrogen fertilizes the old-growth trees.
Sitka spruce in the Tongass can grow to over 60 meters tall and live for more than 800 years. Western red cedar, Alaska yellow cedar, and western hemlock complete the canopy. The forest floor supports a thick carpet of moss, ferns, and berry bushes that sustains an enormous population of Sitka black-tailed deer.
Threats & Conservation
- Main Threats: Logging, road building, mining proposals
- Roadless Rule: Protects ~37,000 km² from road building
- Old-Growth Logged: ~8% of productive old-growth harvested since 1950s
Industrial-scale logging in the Tongass, subsidized by the federal government for decades, has been one of the most contentious environmental issues in American history. Clearcut logging of old-growth trees peaked in the 1980s and 1990s, with timber sold at below-market prices. The Tongass Timber Reform Act of 1990 reduced but did not end old-growth logging.
The Roadless Rule, which protects roughly 37,000 square kilometers of the Tongass from road building, has been the subject of fierce political battles. Mining proposals, including the controversial Pebble Mine near Bristol Bay, also threaten the ecosystem. Conservation groups argue that the Tongass's old-growth forests are worth far more standing than cut, through carbon storage, salmon production, and tourism.
Cultural Significance
- Indigenous Peoples: Tlingit, Haida, and Tsimshian
- Totem Poles: Monumental carved cedar poles
- Subsistence Use: Fish, deer, berries, and traditional medicines
The Tlingit, Haida, and Tsimshian peoples have inhabited the Tongass for at least 10,000 years, developing sophisticated maritime cultures that depended on the forest and the sea. Cedar was central to their material culture, used for longhouses, canoes, totem poles, ceremonial regalia, and bark clothing.
Today, thousands of Alaska Natives continue to rely on the Tongass for subsistence hunting, fishing, and gathering. Salmon remains the single most important food source for many communities. Traditional ecological knowledge accumulated over millennia is increasingly recognized as essential to effective forest management.
Key Facts
- The Tongass is the largest national forest in the United States at 68,000 km².
- It supports all five species of Pacific salmon and roughly 5,000 brown bears.
- Old-growth Sitka spruce in the Tongass can live for over 800 years.
- Salmon carry marine-derived nitrogen into the forest, fertilizing old-growth trees.
- The Tongass stores an estimated 8% of all the carbon in U.S. national forests.
Fun Facts
- A single Tongass salmon stream can support more biomass per square meter than a tropical rainforest.
- Bald eagles gather by the thousands along Tongass rivers during salmon runs, the largest concentration of bald eagles in the world.
- Sitka spruce from the Tongass was used to build aircraft during World War I and II because of its combination of lightness and strength.
- The Tongass contains more than 500 caves, many formed in marble and limestone karst.
Final Thoughts
The Tongass National Forest is America's great temperate rainforest, a landscape where salmon, bears, and ancient trees are linked in one of the most productive ecosystems on Earth. Protecting its remaining old-growth forests is not just an Alaskan issue but a national and global one, as the Tongass stores vast quantities of carbon and supports fisheries worth billions of dollars.