| Summary: | Global warming has had an amplified effect in northern environments (i.e. Arctic and Subarctic regions). An indirect result of this warming is what is known as Arctic greening, which is the increase of photosynthetic material, or plant matter, in Arctic environments. How this greening trend is represented by trees at latitudinal (or northern) treeline is largely unknown. To determine how treeline may respond, I am investigating the physical environment surrounding seedlings found growing at treeline in the Northwest Territories, as well as the reproductive capacity of the mature trees in this region. Physical characteristics of sites which contain seedlings are compared to sites within the same region which do not in an attempt to determine what aspects of these environments are significant in the establishment of seedlings at treeline. Site characteristics include vegetation cover, distance to mature trees, and distance and dimensions of the nearest shrub. Reproductive capacity of mature trees is also tested to determine how significant seed viability may be in generating seedlings in this region. The limiting factor in treeline expansion may be an issue of pre-dispersal (i.e. viable seed production) as opposed to post-dispersal (i.e. seedling growth). I am conducting a germination test where I have extracted seeds from fifteen trees dispersed throughout the treeline region and have placed them under ideal growth conditions for an honest depiction of viable to unviable seed ratios. These tests may show conclusive evidence regarding what factors are contributing to treeline dynamics within a changing environment.
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