Geo 730: July 13, Day 559: Growth Rings

Zooming in from the last post, we're now close enough that the annual growth rings are evident. These form in wood that grows in temperate environments with distinct warm and cold seasons. During the cold weather, growth almost entirely stops, and the cells are much smaller and more densely packed, creating the dark portion of a ring. During warm weather, the cells grow more rapidly, and much larger, creating the lighter portion of each ring. In tropical areas, with no distinct seasons, tree don't show annual growth rings.

 Photo unmodified. March 9, 2012. FlashEarth location.