These descriptions, it will be noticed, apply to trees cut from sixty to one hundred years since. Persons, whom observation has rendered familiar with the present character of the American forest, will be struck with the smallness of the diameter which Dr. Williams and Dr. Dwight ascribe to trees of such extraordinary height. Individuals of the several species mentioned in Dr. Williams's table, are now hardly to be found in the same climate, exceeding one half or at most two thirds of the height which he assigns to them; but, except in the case of the oak and the pine, the diameter stated by him would not be thought very extraordinary in trees of far less height, now standing. Even in the species I have excepted, those diameters, with half the heights of Dr. Williams, might perhaps be paralleled at the present time; and many elms, transplanted, at a diameter of six inches, within the memory of persons still living, measure six, and sometimes even seven feet through. For this change in the growth of forest trees there are two reasons: the one is, that the great commercial value of the pine and the oak have caused the destruction of all the best--that is, the tallest and straightest--specimens of both; the other, that the thinning of the woods by the axe of the lumberman has allowed the access of light and heat and air to trees of humbler worth and lower stature, which have survived their more towering brethren. These, consequently, have been able to expand their crowns and swell their stems to a degree not possible so long as they were overshadowed and stifled by the lordly oak and pine. While, therefore, the New England forester must search long before he finds a pine fit to be the mast Of some great ammiral, beeches and elms and birches, as sturdy as the mightiest of their progenitors, are still no rarity.[250]