fully as important for the most rapid and healthful growth of trees as for the growth of the ordinary crops of the garden or the field. For this purpose they construct open ditches at intervals throughout the forest. In our natural forests, filled with the roots of old trees and often with rocks, it would be difficult to make such ditches. But in many of our low and swampy lands it would be quite practicable, and would add greatly to the amount and value of the growing wood. There is no reason why one should not incur the expense necessary to drain the soil for trees as readily as he does that which he considers desirable for his grass or corn; and all who undertake the planting of trees on new ground should bear this in mind.
We are writing now to urge the importance and even necessity of planting trees on the large scale, as well as the preservation and care of our existing native forests; and one of the first questions to be settled is that of the distance which should separate trees from each other at the time of planting. The experience of European planters has satisfactorily proved that they should be planted much nearer to one another than they are to stand when fully grown. In this respect they should be planted not like the apple or peach orchard, but like the corn-field. One reason why the law of Congress for the promotion of tree-culture has not been more successful is that it allowed trees to be planted twelve feet apart. Trees, when young, are delicate things, and need protection. Like human beings, they seem to have a feeling of companionship. They support and encourage one another. They thrive best when near each other. Accordingly, European foresters commonly plant trees at a distance of not more than four feet apart, and some of our Western planters are disposed to place them even closer than this. Such close planting follows the course of Nature.
If we observe a natural forest, from which destructive animals are excluded, we shall see that the ground is thickly strewed with trees—that few large vacant spaces are to be found, especially when the trees are small. As they increase in size and need more space, Nature has her own way of thinning out. The weaker decay, and the law of the survival of the fittest asserts itself. Following her guidance we have learned to plant closely, and then, from time to time, to make room for the growing trees by transplanting a portion to other fields, or by cutting them and devoting them to such uses as they are fitted for. The smaller serve for hoops for the barrel-maker, or poles for various uses. And so, at all stages of growth, there is an available and profitable use for the trees that seem to be crowding their neighbors.
It is found, again, that trees are not only social in their nature, but that they like variety in their society. As a general thing, different kinds of trees grow better when mixed together than when each kind is planted by itself. This, also, is usually Nature's way of planting. It is common, therefore, for the foresters abroad to plant what they call nurse-trees along with those which they intend to make the staple