Overview:

Impacts of climate change on the boreal forest 

The boreal forest is a vast biome that dominates the northern reaches of North America and Eurasia. In Alaska, the boreal forest is dominated by coniferous trees: primarily white spruce and black spruce. Beyond the boreal forest, in colder climatic zones of very high latitudes and high altitudes, tundra vegetation dominates the landscape. The boundary between the boreal forest and tundra, known as treeline or timberline, generally corresponds to an area in which average July temperatures fall below 10ºC. Because the position of the northern and upper elevational limit of the boreal forest seems to be determined by temperature, a rise in temperature should cause the boreal forest to advance northwards and upwards, displacing tundra ecosystems.

Global warming, or anthropogenic climate change (climate change caused by human activities like fossil fuel burning and land use change), is predicted to cause an overall increase in global temperature of 1.5 to 3.5 ºC. This overall warming, however, is likely to be concentrated at high latitudes which may experience a much larger increase in temperature. The 1995 report of the Intergovernmental Panel on Climate Change contains a comprehensive assessment of what is known and unknown about anthropogenic climate change. Their reports can be accessed by following this link. Our research is focused on understanding the ecological consequences for the boreal forest of such a change in climate. We are investigating the following questions:

1. Has warming in the last 100 years caused a northward or upward expansion in the boreal forest?
2. How has the growth rate and the morphology of individual spruce at treeline changed during the 20th century?
3. How do climate and disturbance interact to control the position of treeline?