Causes of Sun Scald
The reason the sun can cause so much damage to trees is because of dormancy. When a tree is dormant in the winter it can be reactivated by warm weather. In the northern woods trees are exposed to the most sunlight and heat on the southwest facing side, so this side is heated during warm sunny winter days to the point that it can be awoken from dormancy. The temperature required to wake up a tree depends on plant species and length of day, but it is typically just above freezing. Once active, the cells on the southwest side of the plant are unable to return to dormancy by nightfall, at which time the temperature returns to levels capable of killing active cells. Fluctuating winter temperatures can also causes frost cracks, which result from the expanding and contracting of the tree trunk.
Read more about this topic: Sun Scald (flora)
Famous quotes containing the word sun:
“One generation passeth away, and another generation cometh: but the earth abideth for ever. The sun also ariseth, and the sun goeth down, and hasteth to the place where he arose.”
—Bible: Hebrew Ecclesiastes, 1:4-5.
Ernest Hemingway took the title The Sun Also Rises (1926)