Much of this ditch-writing would no doubt be quickly effaced by the flood-action of overflowing streams and rain-washing; but no inconsiderable portion would remain enduringly engraved on ridge-tops beyond such destructive action; for, where all the conditions are favorable, it is almost imperishable.
_Now these historic ditches and root bowls occur in all the present Sequoia groves and forests, but as far as I have observed, not the faintest vestige of one presents itself outside of them_.
We therefore conclude that the area covered by Sequoia has not been diminished during the last eight or ten thousand years, and probably not at all in post-glacial times.
_Is the species verging to extinction?
What are its relations to climate, soil, and associated trees ?_ All the phenomena bearing on these questions also throw light, as we shall endeavor to show, upon the peculiar distribution of the species, and sustain the conclusion already arrived at on the question of extension.
In the northern groups, as we have seen, there are few young trees or saplings growing up around the failing old ones to perpetuate the race, and in as much as those aged Sequoias, so nearly childless, are the only ones commonly known, the species, to most observers, seems doomed to speedy extinction, as being nothing more than an expiring remnant, vanquished in the so-called struggle for life by pines and firs that have driven it into its last strongholds in moist glens where climate is exceptionally favorable.

But the language of the majestic continuous forests of the south creates a very different impression.

No tree of all the forest is more enduringly established in concordance with climate and soil.

It grows heartily everywhere--on moraines, rocky ledges, along watercourses, and in the deep, moist alluvium of meadows, with a multitude of seedlings and saplings crowding up around the aged, seemingly abundantly able to maintain the forest in prime vigor.

For every old storm-stricken tree, there is one or more in all the glory of prime; and for each of these many young trees and crowds of exuberant saplings.