Boreal Forest Health Across the North is Declining Rapidly, Fundamental Changes are Underway

By August 5, 2011 February 2nd, 2013 Forest Mortality

A broad spectrum of ecological indicators are all headed in a negative direction in the Great North. Warming has been identified as the culprit. The more it warms, the greater the impacts. The forests that have evolved with the climate in the North are not at all adapted to the climate up there now. Widespread warming of 5 to 7 degrees has pushed these ecosystems beyond their limits. As a consequence they are stressed and as we all know, stressed life forms tend to be unhealthy. Disease and insects are taking their toll. More, the warmth has brought dryness. Maybe not so much less rain and snow, but more warmth. Each little bit of warmth carries with it four times more evaporations than “cooler” times. this increased evaporation means that plants can be in drought stress with normal or even above normal rainfall. What’s more, many of these plants vascular systems simply can not keep up with the warmer temperatures. They did not evolve with this warmth, and their plumbing is simply undersized.  As a result, the forests of the north are dying and they are taking the wildlife with them. Permafrost is melting, lakes are forming, then drying out and forests are burning like never before in recorded history. The paper says changes in the North are unmatched in 6,000 years.

Abstract: “This paper assesses the resilience of Alaska’s boreal forest system to rapid climatic change. Recent warming is associated with reduced growth of dominant tree species, plant disease and insect outbreaks, warming and thawing of permafrost, drying of lakes, increased wildfire extent, increased post fire recruitment of deciduous trees, and reduced safety of hunters traveling on river ice. These changes have modified key structural features, feedbacks, and interactions in the boreal forest, including reduced effects of upland permafrost on regional hydrology, expansion of boreal forest into tundra, and amplification of climate warming because of reduced albedo (shorter winter season) and carbon release from wildfires. Other temperature-sensitive processes for which no trends have been detected include composition of plant and microbial communities, long-term landscape-scale change in carbon stocks, stream discharge, mammalian population dynamics, and river access and subsistence opportunities for rural indigenous communities. Projections of continued warming suggest that Alaska’s boreal forest will undergo significant functional and structural changes within the next few decades that are unprecedented in the last 6000 years. The impact of these social–ecological changes will depend in part on the extent of landscape reorganization between uplands and lowlands and on policies regulating subsistence opportunities for rural communities.”

http://www.nrcresearchpress.com/doi/abs/10.1139/x10-074