Edward S. Curtis
Trees that struggle with cold and storm.
In yonder grove of pines there are trees of all ages and sizes. The older ones have much the advantage and take a part of the food and sunlight that the smaller ones require. How the little ones stretch up and grow tall and slender in their attempt to get the sunlight! But in spite of all their efforts some of them must die.
Some kinds of trees grow faster than others. Where a number are springing up together, the slow-growing ones will stand less chance of ever becoming great trees. In this way the yellow pine sometimes chokes out the cedar, and the fir gets the advantage of the sugar pine.
The bright, warm sun is the enemy of the tree that loves the shady hillsides. The swamp is the enemy of the tree that must have loose, dry soil. The cold is the enemy of the tree that is used to a hot climate. Is it not strange that what is good for one tree is an enemy of another?
Many kinds of trees have their own particular insect enemies which attack them and no others. Some of these insects live upon the leaves, others eat the sapwood under the bark, while a few attack the roots. Certain insects burrow in and eat the heartwood. Although this does not always kill the tree, it weakens it and makes the wood unfit for use. The cedar and the hickory are among the trees injured in this manner.
The foliage of the broad-leaved trees is the delight of many insects. They sometimes eat the leaves so closely that the tree is killed; for the trees breathe through their leaves and can no more do without them than they can without their roots.
The gypsy moth, which did no great harm in its European home, was brought to this country and accidentally set free. It at once began to attack the leaves of the elm, that beautiful tree of the old New England villages. Now it is destroying other trees and, notwithstanding the fight which we have made against it, we have not yet been able to exterminate it.
American Forestry Association