Arctic Field Projects

Project Title: Collaborative: How the Timing of Summer Precipitation Affects the Responses of Boreal Forest to Climate Change (Award# 0902088)

PI: Lloyd, Andrea H (
Phone: (802) 443.3165 
Institute/Department: Middlebury College, Department of Biology 
IPY Project?
Funding Agency: US\Federal\NSF\GEO\OPP\ARC\ASSP
Program Manager: Dr. Erica Key ( )
Discipline(s): | Biology\Forest Ecology |

Project Web Site(s):

Science Summary:
This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). One of the most striking, seasonal phenomena in the Alaskan boreal forest is the onset of frequent frontal storms in late summer. This event usually comes in mid-July but is delayed into August or even September in some years. Summers when the rains are delayed have a greater chance of being mega-fire seasons when >1.6 million ha burn. This project will test the hypothesis that shifts in the seasonality of warm-season precipitation could be a key driver of the boreal forest’s responses to future climate changes. The effect of late-summer precipitation on tree growth and fire in Alaska will be quantified in two ways: First, by analyzing interactions between climate, fire, and tree growth (specifically ring-width, ring density, and wood-isotope composition); second, by analyzing fire-climate relationships using a new statistical approach. Together, these results will improve parameterization of the forest model ALFRESCO, which will then be used to test additional hypotheses about the interconnections among future climates, tree growth, fire, and their collective feedbacks to the global climate system. The shifting seasonality of water availability during the warm season may be of key importance in determining how the global boreal forest responds to future climate changes. This will be the first time that tree rings from deciduous species in the boreal forest are used to describe past variations in summer rainfall through measurements of ring-width, late-wood density, and wood isotopes. The generalized boosting technique we propose using has not been previously applied to climate-fire records. The results of these tree-ring and statistical analyses will improve parameterization of the ALFRESCO forest model and allow us to explore the interactions among components of this part of the Arctic system with greater realism.

Logistics Summary:
This grant supports a collaboration between 0902169 (Mann, UAF), 0902088 (Lloyd, Middlebury) and 0902180 (Pendall, U of WY). The investigators will study the effects of late-summer precipitation on tree growth and fire in Alaska. During the summers of 2010 and 2011 a field team of four will collect approximately 4000 black spruce cross-sections from sites along a state-wide transect that starts at the forest’s southwestern edge near the Bering Sea coast and ends at the Yukon border in the extreme northeast of the Alaska. Logistic details under 0902169.

The PIs will pay for all logistics through the grant.
SeasonField SiteDate InDate Out#People
2010Alaska - Fairbanks0
2011Alaska - Fairbanks0

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Parameters used to generate this report:, Grant# = "0902088", IPY = "ALL" 
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