86 CALIFORNIA ACADEMY OF SCIENCES. [Proc. 3D Ser. 



smaller branches are consumed and the main trunk becomes 

 accessible, blackened by the fire, the bark more or less 

 burned through, but the wood uninjured. A fire hot enough 

 to burn up so much green rubbish, though not hot enough 

 to impair the value of the great felled trunks as lumber, is 

 surely hot enough to do great damage to the superficial 

 parts of the stump if not to kill it. Such a fire would 

 probably heat the ground enough and deep enough to injure 

 or kill the underground parts, and it would surely destroy 

 all seeds not deeply buried in the soil. Land cleared in any 

 such way as this usually has to be restocked by plants that 

 wander in, their seeds being blown or brought in by wind, 

 animals, man, etc. It seems to me, therefore, that the habit 

 not of the redwood but of the lumberman is responsible for 

 the failure of the northern redwood forest to renew itself. 

 In view of these facts, is it not unnecessary to imagine any 

 harmful change, if change at all, in the climate of the 

 Pacific Coast since the redwoods have lived here ? 



Young redwood trees grown from the seed under some- 

 what artificial conditions often send up suckers from the 

 trunk at or slightly below the level of the ground. A con- 

 siderable number of redwoods in the Arboretum of Stan- 

 ford University are doing so. In some instances this may 

 be due to injury to the upper parts of the tree by fungus or 

 animal enemies, but apparently not in all. It seems to me 

 much more likely that the more abundant branching at the 

 bases of these young trees is a reaction to the larger 

 amount of light which falls upon the surface of the soil and 

 upon the lower parts of the trees in the comparatively open 

 Arboretum than in the natural forest. But the Arboretum 

 is not only more brightly lighted than the forest ; it is warmer 

 by day and colder by night during some if not all seasons 

 of the year; it receives much less moisture both as rain and 

 as fog than the naturally forest-clad hill and mountain sides; 

 and the soil is not able to retain so much moisture because 

 the ground is naked or nearly so. In the natural forest, 

 unharmed by sheep or man, the ground is covered by a 

 thicker or thinner layer composed of humus, decayed 



