Ground tissue in Plants

Count the Annual Rings

How old is the tree in the photo? You can tell by counting the dark lines. The dark spot in the center is the Pith. The first dark line outside the pith is the edge of the first year of growth. Each year of growth consists two bands; a light band followed by a dark band. The light band is the Spring Wood made of large cells which grew when the weather was wet. The dark band is the Summer Wood made of small cells formed when there was less rain. The two bands look different because the small cells of Summer absorb more light and therefore look darker. See the next photo which shows that the dark bands have much smaller cells.