It has been hypothesized that climate change will cause plant species ranges to shift northward with plants at the south end of ranges declining in vigor and growth rate. The purpose of this research is to test this hypothesis for red spruce and balsam fir along the southern end of the continuous distribution of these species, in Massachusetts. By measuring the growth patterns of these trees, we can determine if the southern end of the range has been declining, relative to more northern stands of these species.