Collaborative Proposal: Determining the Vulnerability and Resilience of Boreal Forests and Shrubs across Northwestern North America

DESCRIPTION: The importance of Boreal and Arctic landscapes is recognized by the scientific community as an important area of research. The overarching theory to be tested in this proposal is that the current controls over vegetation growth are not operating as they have been in the past. The investigators have at hand a detailed network of ground measurements of tree-ring data collected across a range of Boreal and Arctic forests and shrublands sites in Alaska and adjacent Canada. This data will be compared with satellite based remote sensing proxies of vegetation productivity. The work is by and large an analysis and comparison of two independent methods for assessing vegetation growth variability in Arctic ecosystems.

OUTCOMES: Key published findings of this research include a study that identified a specific time window in June  for sensitivity of shrub ring widths in northern Alaska, which is in agreement with patterns of satellite observations of vegetation growth. Another study assessed changes in greenness in recent decades in circumpolar Arctic vegetation which was observed at a significant number of the  sites studied, a result  which is in agreement with tree-ring data and field observations. Another paper relates patterns of tundra wildfires to shrub tree rings, remote sensing observations and large-scale warming trends. Together these and other studies resulting from this project provide valuable information on covalidation of ground observations and satellite indices of vegetation, and how the boreal forests and tundra shrub vegetation are responding to the recent and rapid warming of the Arctic.