60 DOMESTICATED ANIMALS AND PLANTS 



have the underground rootstock. Everybody knows that ordinary 

 cutting or pulling avails nothing, for they merely send up new 

 shoots from the buds already formed in the running rootstock 

 under ground. If, however, this new shoot and leaf are killed 

 by cutting off at once, and the next and the next treated in the 

 same way as soon as they appear, the plant will die in time, for 

 it has but a limited number of " buds" and a limited amount of 

 food stored in the stem ; and if it cannot soon get new leaves to 

 the sun for more carbon, it must give up the fight and die. Plow- 

 ing thoroughly once a week for a single season will kill any weed. 



This struggle from overcrowding is best seen in the growth 

 of young trees in the forest. Many more seedlings will start 

 than can possibly live, for a fully matured tree needs and will 

 take a space from ten to fifty and in some cases even one 

 hundred feet across. 



Accordingly when young trees stand thick a struggle at once 

 ensues as to which shall overtop the others and get to the sun- 

 light. The strongest will, of course, be the tallest and get the 

 most light. This in turn gives it more carbon and greater 

 growth, with still further advantage over its fellows, which 

 manage to live as long as they can keep a few leaves in the 

 sunlight, and then die when the failure, which is inevitable, 

 really comes. 



It is interesting and almost pathetic to see the extent to which 

 this struggle for sunlight and life is sometimes carried. The 

 writer once saw a specimen that had recently died out of a 

 thicket of young maples. It was thirty-six feet high, yet was 

 but one and three-fourths inches in diameter at the largest place, 

 so completely had its little growth been converted into height 

 at the expense of size in the vain effort to keep its few leaves 

 bathed in the precious sunlight. This tree never stood quite 

 alone, but leaned helplessly against its stronger neighbors after 

 the fashion of a vine. 



Among the trees that remain, the same principle applies as 

 between the upper and the lower limbs. As new branches start 



