That means that he or she looks for ways to protect the environment from pollution and destruction and tries to teach others how to protect the Earth also. To help archaeologists, an environmentalist tries to understand how the landscape was formed, how people adjusted to the land and climate, and how people helped to change the land. If we understand how people of the past used and changed the land, we can make better choices about how to use the land today. In your unit you will look at tree rings. Tree rings can tell you many things about climate, especially how wet or dry it was.
Tree rings are wider during wet years and more narrow during dry years.
A tree grows one ring each year so you can actually count the rings to see how hold the tree was. This is sometimes used in archaeology sites to tell how old the site is. It is sometimes complicated so special labs have been set up to do the work. You can read a description of the Tree-Ring Research Laboratory at the University of Arizona.