INTERRELATIONS OF LIVING THINGS 39 



preserved to us in our National Parks, a finely adjusted interrelation exists, 

 amounting to a mutual interdependence, by which all the animal and plant 

 species are within them able to pursue their careers down through time 

 successfully. 



The opportunity here to moralize is tempting. If the above course of 

 reasoning be well founded, then, to realize, esthetically and scientifically, 

 the greatest benefit to ourselves from the plant and animal life in Yosemite 

 Park, its original balance must be maintained. No trees, whether living 

 or dead, should be cut down beyond what it may be necessary to remove 

 in building roads or for practical elimination of danger, locally, from 

 fire. Dead trees are in many respects as useful in the plan of nature as 

 living ones, and should be just as rigorously conserved. When they fall, 

 it should be only through the natural processes of decay. The brilliant- 

 hued woodpeckers that render effective service in protecting the living trees 

 from recurrent scourges of destructive insects, in other words, in keeping 

 up the healthy tone of the forest, depend in part on the dead and even the 

 fallen trees for their livelihood. 



No more undergrowth should be destroyed anywhere in the Park than 

 is absolutely necessary for specific purposes. To many birds and mammals, 

 thickets are protective havens which their enemies find it difficult or 

 impossible to penetrate. Moreover, the majority of the chaparral plants 

 are berry-producing and give sustenance to mountain quail, to wild 

 pigeons, to robins and thrushes, to chipmunks and squirrels, and this, too, 

 at the most critical times of the year when other foods for these animals 

 are scarce or wanting. The removal of any of these elements would 

 inevitably reduce the native complement of animal life. Nor do we approve, 

 as a rule, of the destruction of carnivorous animals — hawks, owls, foxes, 

 coyotes, fur-bearers in general — within the Park. Each species occupies 

 a niche of its o%vn, where normally it carries on its existence in perfect 

 harmony on the whole with the larger scheme of living nature. 



