CHAPTER X. 
WARMTH OF TREES IN WINTER AND COOLNESS IN 
SUMMER. 
Temperature of Trees.—Their Winter Warmth and Summer Cool- 
ness.—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. 
Trees have temperature. The shade of some is much 
cooler and pleasanter than others. Ifyou do not believe 
it, try the shade of a maple and then that of a pine, and 
note the difference. 
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 like 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. 
“Tf any one will examine a tree a few hours after the ces- 
sation 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, 
