Hi. I'm Sean Tvelia. We're here at Suffolk County Community College to discuss simple science projects involving dendrochronology. Dendrochronology is the study of time as recorded in tree roots or in plant growth. Now, there are a number of principles that are used in the study of dendrochronology that influence plant growth in any one region, with the most limiting factor actually being the most responsible for tree or plant growth in that area. Most of the time, that limiting is factor is precipitation or moisture. In areas where we have lots of moisture, we expect to see lots of growth and areas where we have limited moisture, little growth. In tree rings, each year a tree is living, one ring is added to the actual trunk. Now, in years of limited precipitation, tree rings are thin; in years of more precipitation, tree rings are thick. Now, we can study environmental conditions in any area simply by recording the number of years and the thickness of those tree rings. And, we could actually use this to study how the environment has changed in any location just by studying the thickness or thinness of tree rings through time, with the newest or most current tree ring being the one on the outer end where the bark is, to the oldest tree ring all the way in the center. And, that is just one simple project that can be done using dendrochronology to study environmental conditions.