Tree-ring climatology

Tree-ring climatology is the part of science that deals with climate study based on the growth rings of trees. The reconstruction of a local climate from growth rings is possible, because there is a correlation between the thickness of a ring and the rainfall or temperatures which were present at the time of its formation. The ring is larger when the climatic conditions of the time are favourable to its growth. Therefore it is possible to study a climate that is hundreds, or even thousands of years old.