New rings form near the bark. Generally, each tree ring indicates a year or a complete cycle of seasons. Thus, the entire period of a tree’s life is reflected by growth rings. Moreover, the thickness and shape of rings show conditions under which they have grown. Hence, the study of tree rings reveals important information regarding the climate and environmental conditions.
What is Dendroclimatology?
Dendroclimatology is a subfield of dendrochronology that utilizes the properties of the annual tree rings to determine past climates. In other words, dendroclimatology uses dated and annually resolved growth rings of trees to reconstruct and analyze past climatic variations. Generally, when environmental conditions are favourable, tree rings become wider. They become narrower when the conditions are not favourable. Moreover, total ring width, earlywood/latewood, wood density of rings are also taken into consideration in dendroclimatology.
Figure 02: Variation of Tree Ring Width, Indicating Summer Temperature Anomalies in the Past 7000 Years