Occasionally, soil conditions, especially with reference to drainage, 

 may be more favorable to the graminaceous vegetation, at least for a time ; 

 giving rise to pampas, prairies and savannahs ; or else all the unfavorable 

 conditions combine to give rise to deserts. 



In addition, there are hostile agencies in the animal world, which pre- 

 vent the progress of forest growth, and tend to preserve the prairies ; lo- 

 custs, rodents, ruminants, like the buffalo, antelope and the horse, impede 

 the growth and spread of the trees, and especially where compact soil and 

 deficient moisture conditions are leagued with these animals, the change 

 from prairie to forest is prevented, at least for a time. 



Woodlands are the most unfavorable form of vegetation for the life 

 of ruminants, and, therefore, for the support of the largest number of men." 

 For food production, for agricultural pursuits, man must subdue and re- 

 move tree growth. Hence, forest devastation, forest destruction, is the 

 beginning of civilization in a forested country, its necessary requisite, and 

 the persistency with which in forest regions the forest tries to re-establish 

 itself calls for continued effort to protect pasture and field against its re- 

 establishment. 



So impressed was Dr. Asa Gray with the persistency of individual tree 

 life that he questioned whether a tree need ever die; "For the 

 tree (unlike the animal) is gradually developed by the successive 

 addition of new parts. It annually renews not only its buds 

 and leaves, but its wood and its roots; everything, indeed, that 

 is concerned in its life and growth. Thus, like the fabled 

 Aeson, being restored from the decrepitude of age to the bloom of youth 

 the most recent branchlets being placed by means of the latest layer of 

 wood in favorable communication with the newly formed roots, and these 

 extending at a corresponding rate into fresh soil why has not the tree all 

 the conditions of existence in the thousandth that it possessed in the hun- 

 dredth or the tenth year of its age ? 



The old central part of the trunk may, indeed, decay, but this is of lit- 

 tle moment, so long as new layers are regularly formed at the circumfer- 

 ence. The tree survives, and it is difficult to show that it is liable to death 

 from old age in any proper sense of the term." 



However this may be, we know trees succumb to external causes, in- 

 sects, fungi, fire, windstorms, etc. Nevertheless, they are perennial enough 

 to outlive aught else, "to be the oldest inhabitants of the globe, to be more 

 ancient than any human monument, exhibiting in some of its survivors a 

 living antiquity, compared with which the mouldering relics of the earliest 

 Egyptian civilization, the pyramids themselves, are but structures of yes- 

 terday." The dragon-trees, socalled, found on the island of Teneriffe, 

 off the African coast, are believed to be many thousand years old. The 

 largest is only 15 feet in diameter and 75 feet high. The sequoias or Big 

 Trees are more rapid growers and attain more than double these dimen- 



