What causes the annual growth rings of trees?

Question

Quizplus · Accepted Answer

Annual growth rings of trees are caused by different growth rates at different times of the year. In the spring and summer, when conditions are favorable, trees grow quickly and produce wood with larger cells, which results in lighter-colored wood. In the fall and winter, growth slows down and wood cells become smaller, resulting in darker wood. Each year of growth produces a distinct ring that can be used to determine the age of the tree.

What Causes the Annual Growth Rings of Trees