State change and vulnerability in the Alaska boreal forest

This research is designed to understand the mechanistic connections among vegetation, the organic soil layer, and permafrost ground stability in Alaska boreal ecosystems. Understanding these linkages is critical for projecting the impact of climate change on permafrost in ecosystems that are subject to abrupt anthropogenic and natural disturbances (fire) to the organic layer.

This project is funded through the US Department of Defense (DoD). The Strategic Environmental Research and Development Program (SERDP) harnesses science and technology to improve DoD’s environmental performance, reduce costs, and enhance and sustain mission capabilities. 

Hypothesis

Major threshold change is more likely to occur in ecosystems that are already at the margins—forests that, historically, are already stressed—and in fires that are at the extremes in terms of size or severity.

  • We expect that severe fires occurring in forest stands that have not experienced deep burning as part of the recent fire cycle will consume a larger proportion of the organic soil layer and have the greatest potential for permafrost destabilization.
  • We hypothesize that drought-stressed forest stands are more likely to shift to an alternate, deciduous, successional trajectory after fire and that moss percent cover and organic soil re-accumulation are negatively related to the percent cover of deciduous canopy tree species.

Objectives

We will work on DoD lands in Interior Alaska to:

  • Monitor vegetation recolonization, soils, and permafrost on a previously existing network of sites located in recent, severe wildfires next to, and on, DoD lands in Interior Alaska.
  • Extend this network to include parallel measurements at sites located in recent prescribed fires and fuel treatments on DoD lands.
  • Study vegetation stand history and organic layer re-accumulation on an established network of mid-successional boreal ecosystems next to, and on, DoD lands.
  • Use models to forecast landscape change in response to projected changes in climate, fire regime, and fire management.