Development of a universal response function to integrate climatic and genetic effects on diameter growth of eastern white pine

The main objective of this study was to develop a universal response function to integrate climatic and genetic effects on the diameter growth of 13 eastern white pine (Pinus strobus L.) provenances planted at seven test sites throughout the part of the species’ native distribution in eastern North America. The test sites (i.e., Wabeno, Wisconsin, USA; Manistique, Michigan, USA; Pine River, Michigan, USA; Newaygo, Michigan, USA; Turkey Point, Ontario, Canada; Ganaraska, Ontario, Canada; and Orono, Maine, USA) examined in this study were part of a range-wide white pine provenance trial established in the early 1960s in the eastern United States and Canada.  Universal response functions of white pine diameter growth were developed that considers the climatic conditions of the trial site location and the seed source locations.  The universal response function for white pine diameter growth that was fully cumulative to the time of sampling indicated that it was affected both by trial site and seed source temperature and precipitation.  Additional universal response functions will be developed for each annual year increment of diameter growth before the main inventory to examine the temporal stability of the universal response functions.  The best universal response function will then be used to project future diameter growth under different climate change scenarios based on different Representative Concentration Pathways (RCP) developed by the Intergovernmental Panel on Climate Change (IPCC).