Temperature of Trees.—Their Winter Warmth and Summer Coolness.—Differences of Temperature of Different Trees Illustrated.— Heat-producing Property of Trees Exemplified.—Local Heating Influence of Forests.—The Additional Property of Evergreens.— Their Twofold Office.
So, too, some trees are warmer in winter than others. "We all know that a stove throws out heat by reason of the fuel it contains, and that in a hke manner the food taken by an animal is, as so much fuel to a stove, the source from whence animal heat is derived, and which is given off to the surrounding atmosphere precisely as heat is given off from the stove; but it is not so well known that trees give off heat in the same way. They feed, their food is decomposed, and during decomposition heat is generated and the surplus given off to the atmosphere. " If any one will examine a tree a few hours after the cessation of a snow-storm, he will find that the snow for perhaps a quarter of an inch from the stem of the tree has been thawed away more or less, according to the severity of the cold. This is owing to the waste heat from the tree. If he plants a hyacinth four inches or more under the surface of the earth in November, and it immediately becomes frozen in and stays frozen solid till March, yet, when it shall then be examined, it will be found that by the aid of its internal heat the bud has thawed itself through the frozen soil to the surface of the ground. These facts show the immense power in plants to generate heat, and the more trees there are on a property the warmer a locality becomes. Evergreens, besides possessing this heat-dispensing property, have the additional property of keeping in check cold winds from other quarters, thus filling as it were, the twofold office of stove and blanket."