Forests of Cascadia: General Facts

Hoh Rainforest WashingtonHoh Rainforest Washington

The Pacific Northwest old-growth forest is a conifer forest, dominated by large, old trees. In the Pacific Northwest, the most common type of old-growth ecosystem is forests dominated by Douglas-firs and western hemlocks, generally 350 to 750 years old. The youngest old-growth forests are 200 years old, and the oldest are about 1,000 years old.

The Pacific Northwest also has old-growth forests dominated by Sitka spruce and western hemlock, along the Pacific Coast, and at higher elevations in the Cascade Mountains, true fir and hemlock old-growth forests.

Among all the forests of the world, the Pacific Northwest old-growth forest is unique because of the size and old age of its trees, the accumulations of biomass (weight and density of living organisms), and the climate, with its wet, mild winters and dry, warm summers.

– No other forest has an entire group of tree species that equals the trees in the Pacific Northwest old-growth forest for their size and long lives. Some of California’s giant redwoods are bigger than the biggest Douglas-fir tree. But several species of big trees grow in the Pacific Northwest old-growth forest, not just one. In other forests, some junipers and bristlecone pines live longer. But several species of trees live for hundreds of years in the Pacific Northwest old-growth forest, not just one.

Scientists have done a lot of research on old-growth forests in the last 30 years. Much of this work was done by Pacific Northwest Research Station scientists. Click on the other headings on this page to learn more about Pacific Northwest old-growth forests.

British Columbia, Canada’s western-most province, covers 95 million hectares (235 million acres) – larger than any European country except Russia, and larger than any U.S. state other than Alaska. Only 30 countries in the world are bigger. B.C. is characterized by its abundant forests, rugged Pacific coastline, mountainous terrain, plateaus, and numerous lakes and rivers. Forests cover close to two-thirds of the province – an area of almost 60 million hectares (149 million acres). These vast forests are at the heart of B.C.’s history and its current way of life. For thousands of years, aboriginal peoples have looked to the forest for shelter, clothing, food, tools and medicine.

British Columbia is Canada’s most ecologically diverse province. It has the country’s only temperate desert, near Osoyoos in the far south, and North America’s wettest weather station, on the west coast of Vancouver Island. It has temperate rainforests, dry pine forests, boreal forests, alpine tundra, grasslands and more. Historically, this diversity has presented a challenge to resource managers who want their actions to match the needs of each unique ecosystem . B.C.’s rich forest diversity includes more than 40 different species of native trees, with some of Canada’s most interesting and valuable tree species. Coniferous, or softwood, species such as pine, spruce, fir, hemlock and western redcedar are predominant in close to 90 per cent of B.C.’s forests. Most of the remaining forests are a mix of coniferous and broadleaf, or hardwood, species.

In Washington, the Hoh Rainforest represents the wettest, and some of the largest forests in the state. Throughout the winter season, rain falls frequently in the Hoh Rain Forest, contributing to the yearly total of 140 to 170 inches (or 12 to 14 feet!) of precipitation each year. The result is a lush, green canopy of both coniferous and deciduous species. Mosses and ferns that blanket the surfaces add another dimension to the enchantment of the rainforest. The Hoh Rain Forest is located in the stretch of the Pacific Northwest rainforest which once spanned the Pacific coast from southeastern Alaska to the central coast of California. The Hoh is one of the finest remaining examples of temperate rainforest in the United States and is one of the park’s most popular destinations.

Oregon also contains 6 of the largest 10 old growth forests remaining in the United States, and is one of the largest carbon sinks in the world. It’s not just live trees – carbon is also stored in dead wood, roots, and other plants. And of those forests, the older they are, the more carbon they can store. The Pacific Northwest’s temperate rainforests are among the greatest biomass stores per acre of any ecosystem on Earth! This is why, in terms of storing carbon, all ten of the largest forests are here in Cascadia.

Top 10 Carbon Capturing Forests in the US

  1. Willamette (OR)

  2. Olympic (WA)

  3. Umpqua (OR)

  4. Gifford Pinchot (WA)

  5. Siuslaw (OR)

  6. Mount Hood (OR)

  7. Mount Baker – Snoqualmie (WA)

  8. Siskiyou (OR)

  9. Tongass (AK)

  10. Rogue River (OR)

A U.S. Forest Service study found that forests in Oregon, Washington and California store 20.5 billion metric tons of carbon. That is 39 percent of total forest carbon in the U.S. and close to two percent of carbon stored in world forests.

The earliest redwoods showed up on Earth shortly after the dinosaurs—and before flowers, birds, spiders… and, of course, humans. Redwoods have been around for about 240 million years, compared to about 200,000 years for “modern” humans.

Before the 1850s, coast redwoods (Sequoia sempervirens) luxuriated amongst some 2 million acres of California’s coast, stretching from south of Big Sur to just over the Oregon border. One of three members of the Sequoioideae subfamily of cypress trees, the coast redwoods and their cousins, the giant sequoias (Sequoiadendron giganteum), hold the records for tallest and largest trees in the world, respectively.

For thousands of years the people of the area managed to live in harmony with these ancient trees, understanding the importance of their unique forest ecosystem. And then the gold rush happened. With the arrival of hundreds of thousands of gold-seekers starting in 1849, the redwoods were doomed. Logged into near oblivion to keep up with the demand for lumber, today, only 5 percent of the original old-growth coast redwood forest remains, fewer than 100,000 acres dotted along the coast.

Coast redwoods are among the oldest living organisms in the world. They can live for more than 2,000 years – which is to say, some of these grande dames were alive during the Roman Empire. The oldest living redwood known clocks in at around 2,200 years old. Aside from the pockets of old-growth, most of the coast redwood forest is now young.

Attaining soaring heights of more than 300 feet, they are so tall that their tops are out of sight. The tallest one of all is a towering beauty by the name of Hyperion; discovered in 2006, this giant stands at 379.7 feet in height. Trees store carbon dioxide, which makes them an important ally in fighting climate change. But according to research, coast redwoods store more CO2 than any other forest in the world They hold 2,600 metric tons of carbon per hectare (2.4 acres), more than double the absorption rate of the Pacific Northwest’s conifer trees or Australia’s eucalyptus forests. Your local coast redwood tree can grow to 300 feet or more—the tallest tree on Earth. Right now, there are about 50 redwood trees taller than 360 feet living along the Pacific Coast. Compare that to the tallest pine tree at 268 feet, the tallest tanoak at 162 feet or the tallest human at a mere 8 feet 3 inches. Yet their root system is only 6 to 12 feet deep. Redwoods create the strength to withstand powerful winds and floods by extending their roots more than 50 feet from the trunk and living in groves where their roots can intertwine. Redwoods are quite an armful to hug, too—8 to 20 feet in diameter.

The headwaters of the Snake River begin at the very peak of the Yellowstone Caldera and define the bioregion’s eastern border. At 3,472 square miles—over 2.2 million acres—Yellowstone is larger than the states of Rhode Island and Delaware combined. The vast majority of its territory is situated in Wyoming, but it also creeps into neighboring Montana and Idaho. This supervolcano is immense, and it’s eruption some 640,000 years ago is a strong reminder of the dynamism of the Cascadia bioregion. The system is still considered active and contains a reservoir of magma big enough fill the Grand Canyon several times over. While scientists are not concerned about an eruption occurring any time soon—the last was some 640,000 years ago—the volcano is powerful enough to potentially shroud much of the continental United States in ash.