The study of water uptake and root cold hardiness at low soil temperatures in four commercially important tree species (Abies amabilis, A. lasiocarpa, Pinus contorta and Tsuga mertensiana) from both the Pacific Coast and the Rocky Mountain regions will result in information with application in basic biology and woody plant physiology, as well as in applied biology. Basic biological and physiological applications include (1) an understanding of the tradeoff between maintenance of root absorptive function at low soil-root temperatures versus the ability of the root to tolerate cold, subfreezing temperatures and how this tradeoff influences the success of species, normally associated with continental and maritime climates, when found in the opposite climatic regime, (2) the role of low soil temperatures in affecting productivity of mid and high elevation woody plants and (3) an estimation of the relative importance of belowground as opposed to aboveground processes in regulating plant/tree function. This study will have applied application in the areas of forest management and wilderness and parkland management. Within forest management, particularly given the mandates of various state and federal regulations (described under the appropriate Forest Practices Acts), this study will provide information useful to (1) site selection for regeneration, (2) microsite and site constraints on regeneration and productivity, (3) an understanding of the role of stand development on altering site microclimate and the resultant impacts on tree mortality and (4) the prediction of the impact of site and climate modification on tree mortality.
