What are tree rings and what do they tell us?
Each year, as trees or woody shrubs grow, they produce wood cells that form a ring around the circumference of the trunk. The width of a tree ring and other factors (like the density of the cells) reflect environmental conditions (such as moisture and temperature) experienced during the growing season. Information on annual tree rings is compiled into chronologies of standardized growth rates for each year. These chronologies provide a record of environmental conditions observed at that location; when combined together, they tell us about past climate. Researchers from the Tree-Ring Lab at the Lamont-Doherty Earth Observatory use tree-ring chronologies from Asia, the Americas and Siberia to improve our understanding of past environmental conditions. These chronologies provide information about regional weather patterns, teleconnections between climate conditions at distant locations, and human impacts on forest growth.
