Boreal Biome

The circumboreal belt of forest represents about 30% of the global forest area, contains more surface freshwater than any other biome, and has large tracts of unmanaged forests across the high-latitude regions of Canada, Russia, and the United States. From a biological perspective, boreal forests are defined as forests growing in high-latitude environments where freezing temperatures occur for 6 to 8 months and in which trees are capable of reaching a minimum height of 5 m and a canopy cover of 10%.

• Is the world’s largest intact forest ecosystem. It stretches across 1.2 billion acres (485 million hectares) of northern Canada, from the Yukon to Newfoundland and Labrador.

• Represents 25 percent of the world’s remaining intact forest, even more than the Amazon rainforest.

• Contains 25 percent of the world’s wetlands.

• Includes more surface freshwater—about 200 million acres (81 million hectares)—than anywhere else on Earth.

• Is North America’s bird nursery. Each year, 1 billion to 3 billion birds migrate north from the United States—and from as far away as South America—to nest in Canada’s boreal forest. Between 3 billion and 5 billion return south each fall after a successful breeding season.

• Stores twice as much carbon per acre as tropical rainforests. In all, Canada’s boreal forests and peatlands lock in a minimum of 229 billion tons of carbon. Peatlands, also known as bogs and fens, are wetlands that include vegetation such as sphagnum mosses, shrubs, and spruce. This natural carbon storage helps cool the planet and provides a critical bulwark against climate change.

• Is home to some of the cleanest and deepest freshwater lakes on the planet. Great Bear Lake, in the Northwest Territories, is considered the world’s largest unpolluted lake. Great Slave Lake, also in the Northwest Territories, is North America’s deepest.

During its relatively brief history since deglaciation, the boreal forest has experienced many fluctuations of its climatic environment. The current warming trend experienced by northern latitudes is, however, unprecedented in its speed and projected amplitude, and is also more pronounced than in the rest of the world. Resulting impacts are numerous and include the melting of permafrost, changes in tree growth rates, increased incidences of wildland fire, and changes in the dynamics of insect outbreaks. The causal links among these changes and their implications for the functioning of the boreal forest and the services it provides to local and global populations are not yet completely understood.