192 THE MOUNTAINS OF CALIFORNIA 



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 squir 

 rel, 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 mis 

 apprehended, 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 in 

 creasing drought will of itself extinguish Sequoia, 

 leaving its ground to other trees supposed capable 

 of flourishing 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 1 " Sim 

 ply 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. 



