We often read that oaks are springing up in destroyed forests where oaks had never grown before. The writers are no doubt sincere, but they are careless. The only pine forests where oaks are not intermixed are either in land so sandy that oaks cannot be made to grow on them at all, or so far north that they are beyond their northern limit. In the Green Mountains and in the New England forests, in the pine forests in Pennsylvania, in the Adirondacks, in Wisconsin and Michigan--except in sand--I have found oaks mixed with the pines and spruces. In northwestern Minnesota and in northern Dakota the oaks are near their northern limit, but even there the burr oak drags on a bare existence among the pines and spruces. In the Black Hills, in Dakota, poor, forlorn, scrubby burr oaks are scattered through the hills among the yellow pines. In Colorado we find them as shrubs among the pines and Douglas spruces. In New Mexico we find them scattered among the pinons. In Arizona they grow like hazel bushes among the yellow pines. On the Sierra Nevada the oak region crosses the pine region, and scattering oaks reach far up into the mountains. Yet oaks will not flourish between the one hundredth meridian and the eastern base of the Sierras, owing to the aridity of the climate. I recently found oaks scattered among the redwoods on both sides of the Coast Range Mountains. Darwin has truly said, "The oaks are driving the pines to the sands." Wherever the oak is established--and we have seen that it is already established whereever it can endure the soil and climate--there it will remain and keep on advancing. The oak produces comparatively few seeds. Where it produces a hundred, the ash and maple will yield a thousand, the elm ten thousand, and many other trees a hundred thousand. The acorn has no provision for protection and transportation like many tree seeds. Many kinds are furnished with wings to float them on the water and carry them in the air. Nearly every tree seed, except the acorn, has a case to protect it while growing, either opening and casting the seeds off to a distance when ripe or falling with them to protect them till they begin to germinate. Even the equally large seeds of other kinds are protected in some way. The hickory nut has a hard shell, which shell itself is protected by a strong covering until ripe. The black walnut has both a hard shell and a fleshy covering. The acorn is the only seed I can think of which is left by nature to take care of itself. It matures without protection, falls heavily and helplessly to the ground, to be eaten and trodden on by animals, yet the few which escape and those which are trodden under are well able to compete in the race for life. While the elm and maple seeds are drying up on the surface, the hickories and the walnuts waiting to be cracked, the acorn is at work with its coat off. It drives its tap root into the earth in spite of grass, and brush, and litter.