The trained Forester must know the forest as a doctor knows the human machine. First of all, he must be able to distinguish the different trees of which the forest is composed, for that is like learning to read. He must know the way they are made and the way they grow; but far more important than all else, he must base his knowledge upon that part of forestry which is called Silvics, the knowledge of the relation of trees to light, heat, and moisture, to the soil, and to each other.

The well-trained Forester must also know the forest shrubs and at least the more important smaller forest plants, something of the insect and animal life of his domain, and the birds and fish. He must have a good working knowledge of rocks, soils, and streams, and of the methods of making roads, trails, and bridges. He should be an expert in woodcraft, able to travel the forest safely and surely by day or by night. It is essential that he should have a knowledge of the theory and the practice of lumbering, and he should know something about lumber markets and the value of lumber, about surveying and map making, and many other matters which are considered more at length in the Chapter on Training. There are as yet in America comparatively few men who have acquired even fairly well the more important knowledge which should be included in the training of a Forester.