Understanding site specific climate-growth relationships for ring widths and δ13C values of white spruce (piceaglauca) in the interior Alaska

• Main Author: Muldoon, Laurel Ann
• Other Authors: Csank, Adam, James, April, Nipissing University, Faculty of Arts and Science
• Format: Thesis
• Language: English
• Published: Nipissing University 2019
• Subjects: White spruce; Tree-rings; Trees; Plants; Denali National Park and Preserve (Alaska); Kantishna River Watershed (Alaska); Arctic; Climate change; Moose; Alaska
• Online Access: http://hdl.handle.net/1807/100424

This thesis was completed and submitted at Nipissing University, and is made freely accessible through the University of Toronto’s TSpace repository Projected increases in climate at high latitude regions and the implications of these changes provide a stimulus to study arctic environments. Interior Alaska, located within the arctic, is described as being semi-arid. The boreal forest covers approximately covers approximately 300,000 km2 of land within the Interior Alaska, with the dominant tree species being white spruce (Picea glauca). Studies have found that temperature induced drought stress is a major factor contributing to the health and growth of a tree. This study explores climate-growth relationships (temperature and precipitation) for white spruce (Picea glauca) in Interior Alaska and involves the analysis of white spruce (Picea glauca) tree-ring widths, δ13C (stable carbon isotopes) in conjunction with temperature (monthly averages) and precipitation (monthly sums)from 1980 to 2010. It covers a 30-year period from 1980-2010 explicitly chosen to explore the implications of climate change on the boreal forest in Interior Alaska given the sudden rise in atmospheric warming and projected trend to increase. The use of 6 tree cores located in floodplains (Lower Moose site) and 6 tree cores located upland (Kantishna site) are sampled within Denali National Park and Preserve to investigate site specific characteristics. Overall, negative correlations were found between summer temperature and RWI and negative correlations between spring/winter precipitation for both Lower Moose and Kantishna. Positive(enrichment) correlations between δ13C and temperature prevail for summer months. Weak to no correlations are present for both Lower Moose and Kantishna with precipitation. Kantishna had minimal correlations as a site overall, indicating that climate does not account for all variability found within these trees. In addition, Lower Moose had stronger correlations providing future researchers with the need to investigate lowland floodplain trees further. M.E.Sc.