SUMMARY
Climate change in North America is anticipated to contribute to higher tree mortality as a result of increasing temperatures, lower annual snowpack, and prolonged summer drought periods (IPCC, 2014; Chen et al., 2010; Hogg et al., 2008). This poses a significant problem for scientists, policy makers, and forest managers as the historical range and distribution of many tree species has been changing as a result of regional warming and periods of extreme weather events. Though annual temperatures are increasing across the continent, it is hypothesized that higher temperatures and longer growing seasons could benefit forest productivity in areas where annual precipitation levels are sufficiently high (D’Orangeville et al., 2016). Conversely, areas that are already precipitation limited are anticipated to be negatively impacted by increasing atmospheric temperatures.
One way to assess how climate influences the growth of a particular species in a given area is to study the tree-rings from a forest stand which can provide a historical record of previous growing conditions, dating back hundreds of years. By studying the past relationship between climatic conditions and radial growth for white spruce and lodgepole pine across North America, it is possible to shed light on how this species might be affected by future climate change. I analyzed historical climate data and raw tree-ring data of both white spruce and lodgepole pine, two highly valuable forest species that account for up to 80% of trees planted annually in Alberta (Grey & Hamann, 2015). From there, I created 191 master chronologies which were then used as part of bootstrapped response function analysis to determine which historical climatic variable have been limiting the growth at each chronology site. Since the lodgepole pine dataset was not robust enough, these data were not included in the final analysis.
Cluster analyses were conducted using a partitioning around mediods algorithm to create 6 distinct climate groups and 6 response function groups. These groups were then mapped across North America to visualize which populations of white spruce are currently vulnerable to drought. With ongoing climate warming anticipated in the future, white spruce populations in interior regions of Alaska and the western boreal forest are the most susceptible to climate change when compared to their coastal and eastern counterparts.
DISCLAIMER: This is a class exercise based on modified or randomly generated datasets, and this website is developed only for the purposes of the RENR 690 course.
Climate change in North America is anticipated to contribute to higher tree mortality as a result of increasing temperatures, lower annual snowpack, and prolonged summer drought periods (IPCC, 2014; Chen et al., 2010; Hogg et al., 2008). This poses a significant problem for scientists, policy makers, and forest managers as the historical range and distribution of many tree species has been changing as a result of regional warming and periods of extreme weather events. Though annual temperatures are increasing across the continent, it is hypothesized that higher temperatures and longer growing seasons could benefit forest productivity in areas where annual precipitation levels are sufficiently high (D’Orangeville et al., 2016). Conversely, areas that are already precipitation limited are anticipated to be negatively impacted by increasing atmospheric temperatures.
One way to assess how climate influences the growth of a particular species in a given area is to study the tree-rings from a forest stand which can provide a historical record of previous growing conditions, dating back hundreds of years. By studying the past relationship between climatic conditions and radial growth for white spruce and lodgepole pine across North America, it is possible to shed light on how this species might be affected by future climate change. I analyzed historical climate data and raw tree-ring data of both white spruce and lodgepole pine, two highly valuable forest species that account for up to 80% of trees planted annually in Alberta (Grey & Hamann, 2015). From there, I created 191 master chronologies which were then used as part of bootstrapped response function analysis to determine which historical climatic variable have been limiting the growth at each chronology site. Since the lodgepole pine dataset was not robust enough, these data were not included in the final analysis.
Cluster analyses were conducted using a partitioning around mediods algorithm to create 6 distinct climate groups and 6 response function groups. These groups were then mapped across North America to visualize which populations of white spruce are currently vulnerable to drought. With ongoing climate warming anticipated in the future, white spruce populations in interior regions of Alaska and the western boreal forest are the most susceptible to climate change when compared to their coastal and eastern counterparts.
DISCLAIMER: This is a class exercise based on modified or randomly generated datasets, and this website is developed only for the purposes of the RENR 690 course.