A NEW DENDROCLIMATIC NETWORK OF TEMPERATURE-SENSITIVE, TREE-RING SERIES FROM GLACIER BAY NATIONAL PARK AND PRESERVE, ALASKA

Multi-species tree-ring chronologies from old growth forests in the Glacier Bay National Park and Preserve, Alaska are sensitive primarily to summer temperature and have been used to infer past temperature variability and to reconstruct summer glacier mass balance. Recent collections of mountain and western hemlock, lodgepole pine, and yellow cedar are being developed to examine the climatic response of these species and to determine their potential in reconstructing ocean – atmosphere climate variability. In addition, these tree-ring data can be used to assess future forest productivity in a changing climate.

Preliminary analysis of the established Beartrack hemlock ring-width series from Glacier Bay extends to AD1569 and spans a significant portion of the Little Ice Age (LIA). The other species similarly date back to the mid to late 1500s for the cedar and at least 300 years for the pine. These past several hundred years bridge the transition of cooling during the LIA and strong winter warming in the Glacier Bay region of the Gulf of Alaska. The Beartrack tree-ring chronology suggests a complex response of trees with warming and glacier retreat in Glacier Bay; some trees are increasing their growth and others are declining in ring-width. These data are relevant to the contribution of the southern coastal Alaskan forests to the carbon cycle as well as our ongoing efforts to use ring-width series in dendroclimatic reconstruction.