I also noted eighty-six vigorous saplings upon a piece of fresh ground prepared for their reception by fire.  Thus fire, the great destroyer of Sequoia, also furnishes bare virgin ground, one of the conditions essential for its growth from the seed.  Fresh ground is, however, furnished in sufficient quantities for the constant renewal of the forests without fire, viz., by the fall of old trees.  The soil is thus upturned and mellowed, and many trees are planted for every one that falls.  Land-slips and floods also give rise to bare virgin ground; and a tree now and then owes its existence to a burrowing wolf or squirrel, but the most regular supply of fresh soil is furnished by the fall of aged trees.

The climatic changes in progress in the Sierra, bearing on the tenure of tree life, are entirely misapprehended, especially as to the time and the means employed by Nature in effecting them.  It is constantly asserted in a vague way that the Sierra was vastly wetter than now, and that the increasing drought will of itself extinguish Sequoia, leaving its ground to other trees supposed capable of nourishing in a drier climate.  But that Sequoia can and does grow on as dry ground as any of its present rivals, is manifest in a thousand places.  “Why, then,” it will be asked, “are Sequoias always found in greatest abundance in well-watered places where streams are exceptionally abundant?” Simply because a growth of Sequoias creates those streams.  The thirsty mountaineer knows well that in every Sequoia grove he will find running water, but it is a mistake to suppose that the water is the cause of the grove being there; on the contrary, the grove is the cause of the water being there.  Drain off the water and the trees will remain, but cut off the trees, and the streams will vanish.  Never was cause more completely mistaken for effect than in the case of these related phenomena of Sequoia woods and perennial streams, and I confess that at first I shared in the blunder.

When attention is called to the method of Sequoia stream-making, it will be apprehended at once.  The roots of this immense tree fill the ground, forming a thick sponge that absorbs and holds back the rains and melting snows, only allowing them to ooze and flow gently.  Indeed, every fallen leaf and rootlet, as well as long clasping root, and prostrate trunk, may be regarded as a dam hoarding the bounty of storm-clouds, and dispensing it as blessings all through the summer, instead of allowing it to go headlong in short-lived floods.  Evaporation is also checked by the dense foliage to a greater extent than by any other Sierra tree, and the air is entangled in masses and broad sheets that are quickly saturated; while thirsty winds are not allowed to go sponging and licking along the ground.