We frequently pass them by and pay no heed, but trees are constantly at work. One of the things they are doing is producing wood and that wood shows up as annual rings that we can see on pieces of wood that are cut in a radial section (think of a tree stump). These rings are a natural archive of information about the tree’s environment and can be harnessed to tell many stories about the tree and its environment.
Counting the number of rings near the base of a tree we can get a very good estimate of the age of a tree. By understanding the age of a wide number of individuals on a landscape we can gather demographic information (how old are individuals, when did they start to grow, what spatial patterns do they show on the landscape) and get a sense of how the landscape has changed over the past several hundred years (depending on the age of living and dead trees).
Tree rings can also provide insight into the growing conditions of a tree and what factors contribute to better or worse growth. By measuring ring width and other possible measurements such as wood density or perhaps isotopes contained in the wood, we can understand how climate influences growth and how that might change in the future.
This summer, we will be collecting samples primarily concerned with the first task above in order to understand how the treeline (the area of transition between the subarctic tundra and the boreal forest) has changed over the past 200 years.