| Autor: |
Dial RJ; Institute for Culture and Environment, Alaska Pacific University, Anchorage, AK, USA., Maher CT; Environment and Natural Resources Institute, University of Alaska Anchorage, Anchorage, AK, USA., Hewitt RE; Center for Ecosystem Science and Society, Northern Arizona University, Flagstaff, AZ, USA., Wockenfuss AM; Institute for Culture and Environment, Alaska Pacific University, Anchorage, AK, USA., Wong RE; Institute for Culture and Environment, Alaska Pacific University, Anchorage, AK, USA., Crawford DJ; Environment and Natural Resources Institute, University of Alaska Anchorage, Anchorage, AK, USA., Zietlow MG; Institute for Culture and Environment, Alaska Pacific University, Anchorage, AK, USA., Sullivan PF; Environment and Natural Resources Institute, University of Alaska Anchorage, Anchorage, AK, USA. |
| Abstrakt: |
Climate-induced northward advance of boreal forest is expected to lessen albedo, alter carbon stocks, and replace tundra, but where and when this advance will occur remains largely unknown. Using data from 19 sites across 22 degrees of longitude along the tree line of northern Alaska, we show a stronger temporal correlation of tree ring growth with open water uncovered by retreating Arctic sea ice than with air temperature. Spatially, our results suggest that tree growth, recruitment, and range expansion are causally linked to open water through associated warmer temperatures, deeper snowpacks, and improved nutrient availability. We apply a meta-analysis to 82 circumarctic sites, finding that proportionally more tree lines have advanced where proximal to ongoing sea ice loss. Taken together, these findings underpin how and where changing sea ice conditions facilitate high-latitude forest advance. |
