Lvi] 



and the ground immediately around it in which the roots are grow- 

 ing. As the tree grows, it preserves a symmetrical shape, the limbs 

 spreading and the trunk increasing in size, in proportion to its 

 height, but always preserving the condition of keeping the trunk 

 and the ground for a considerable distance around it, in the shadow 

 of the foliage till mature age, when the roots have penetrated to 

 such a depth as to be safe from injury, and the trunk is protected 

 by thick layers of cork like bark, which safely guards alike from 

 heat and cold the inner layers and young wood in which the sap is 

 performing its functions. 



Such are the conditions to which nature adheres, if not interfered 

 with by accident or design, and such, therefore, we may be sure, 

 are those best adapted to healthy and vigorous growth. The fact 

 that they are continually violated with apparent impunity, serves 

 only to show the wonderful power of nature to supply deficiencies, 

 and adapt herself to circumstances, but in artificial culture, we 

 should aim as nearly as possible to imitate the course she would 

 pursue if unimpeded. 



The requirements of nature are of course the same when trees are 

 growing together in a forest, as when they stand singly, but the 

 conditions of growth are so changed that the end is attained by 

 entirely different means. 



If we enter a tract of wood land, covered with a hard wood growth 

 of an average height of thirty or forty feet we find it composed 

 almost exclusively of trees which have run up to a great height in 

 proportion to the spread of their limbs. The largest and oldest of 

 them may have had some lateral branches which are now dead, 

 but the younger growth will consist only of tall, slender stems, with- 

 out a branch or leaf except near the top. It will be difficult, per- 

 haps impossible, to find a single tree possessing sufficient symmetry 

 of form to be worth transplanting for ornamental use. A little 

 reflection will serve to convince us that this form of growth, so 

 different from that of the single tree in the open ground, is the 

 natural result of the action of the same rules under changed con- 

 ditions. 



When a young wood first springs up on open ground, each tree 

 begins to grow as if it were alone, sending out lateral branches 

 and preserving its just proportion. But whenever these laterals 

 meet and mingle with each other, they shut out the sunlight from 

 all below, and thence forward all lateral growth must cease, and 

 each individual is struggling upward to keep even with its neiglibors 

 and secure its share of the sunbeams which are essential to its 

 existence, and which can only be had at the top. It thus becomes 

 forced out of all just proportions in the effort to keep even with its 

 fellows. The conditions of keeping the trunk and roots in the shade, 

 however, are even more rigidly adhered to than in the case of the 

 single tree, growing by itself, for the whole area of the wood is 

 shaded, and, moreover, the trees on the edges of the wood, if not 

 interfered with by men or cattle, will be clothed on the outer side 

 with limbs and foliage, clear to the ground, so as to check the free 

 passage of the winds whose drying influence upon the soil is even 

 more active than that of the sun. 



