Tree Growth Rings: The Story They Can Tell

“Growth Rings” of trees or “Annual Growth Rings” are concentric circles of new cells which a tree produces during one growing season.  A tree gets larger in diameter because it manufactures new cells around it’s circumference.  The tree’s annual rings are biological indicators which can reveal environmental events that have occurred, over a tree’s lifespan.

By looking at a cross-section of a tree’s stump or log, one can visibly see rings that can tell a story of what the growing season was like many years in the past.  A good growing year, with warm, wet weather, will produce wider concentric circles, while dry, cooler years will produce narrower ones.

Forest fires, insect infestations and even distant volcanic eruptions, have been recorded within the rings of ancient trees.  In Canada, which has a distinct winter dormancy season, growth rings are used to calculate an accurate age, of trees.  The scientific method of dating tree rings, is known as “Dendrochronology”, which has been used to date some of Canada’s oldest trees.