Scientists have always studied trees to learn about the changes in geography, but nowadays they are looking at the rings in the tree to determine something else. They are examining the width of the rings so they can make an estimate about the temperature patterns. If they see large rings, they know that the tree grew more in one season which means summer temperatures were higher than usual. They are also analyzing carbon and oxygen isotopes. They take a sample of the tree ring and then measure the isotope levels, which also yields data on weather patterns in the past.
Yes, it could be helpful to study tree rings, because they are giving us pieces of info about not only the past climate , but also the changes happened throughout ages. This kind of information is given by the carbon and oxygen isotopes found in tree rings.
It's important to take the study but to pay attention to the factors that are influencing the size of trees analyzed. For example, boreal forest has small size trees, but incredibly old. So a diameter of maximum 20cm could mean that the tree is about 400 years. But not only the location of the forest is an important growth factor, also the place occupied by the tree within the forest is important , too, because, in the same area, substances (water, nutrients) essential for growth and life of the tree, may vary.
The study of trees provides a lot of answers about the past. As trees grow the trunk of the tree develops a circular pattern created by the sap of the tree. The inner rings eventually are surrounded by outer rings as the process continues. In years when weather conditions are dry the rings show less growth between rings. In seasons when the climate is moist the rings are often thicker. Other conditions of the rings such as the color and thickness of the ring can demonstrate the response to extreme cold or warmth. For example during a warm climate a tree ring is thicker. Thinner rings indicate a cold snap. By observing the pattern of the rings scientists are able to obtain information about the climate changes that surrounded the tree during its growth.