Tree Rings

Tree rings are one of the many proxies used to estimate the past's climate changes. As a tree grows in a year it produces a new ring, which varies in width allowing us to estimate the climate due to how much the tree grew. The trees that we focus on are normally found in a temperate climate, where they have a dry season. The trees that do not have a dry season end up growing year round and that makes it hard to determine any climate changes because the rings are not defined to one per year. The trees growth are influenced by precipitation, temperature, sunlight and wind. All of these factors can help us determine the climate of that specific growing season. Trees can grow for thousands of years and hold data from all of the past climates. When the tree rings are thicker that normally points toward a climate that favors the growth of the trees, while having narrow means the opposite. With the amount of data that has been collected scientists are able to estimate from hundreds to thousands of years in the past locally. By combining this proxy with other proxies scientists have been able to estimate regional and global climates.