132 



VITALITY AND LONGEVITY IN FRUIT TREES. 



as a man by external mutilations, that there- 

 fore it could scarcely be killed or injured 

 at all. But recent observations tend wholly 

 in one single direction ; that is, towards 

 establishing a close and hitherto unsus- 

 pected analogy between the functions and 

 powers of life, both in the animal and the 

 veo-etable world ; and sound philosophy 

 should lead us to suspect, rather than 

 otherwise, that such analogies actually ex- 

 ist in multitudes of cases where they have 

 not as yet been demonstrated. 



Another effect of pruning the trunks of 

 trees severely, results from disturbing the 

 natural relations of the ascending and de- 

 scending sap. The ascending s.ip goes up 

 in the wood ; the descending returns by the 

 bark. It is near enough the truth for illus- 

 tra'ion, to say that the capacity of ascent is 

 most nearly proportioned to the solid con- 

 tents, while the capacity of descent is nearer 

 to the superficial contents of the trunk or 

 branch in all young trees. Hence, the ca- 

 pacity of ascent increases as the square of 

 the surface, or near that ratio, while the 

 capacity of descent increases only as the 

 surface. Hence, where trunks are exposed 

 to the sun, or where plenty of light and air 

 is found for the leaf, nature commences her 

 work of dividing the trunk into branches 

 near the ground, so as to increase the sur- 

 faces for the return sap, while the interi- 

 or contents are proportionally diminished 

 through which the current rises ; and the 

 richer the soil the greater the necessity of 

 this increase of surface for the return sap ; 

 and hence the constant effort, in such soils, 

 in trees to throw out branches from the 

 trunk near the ground when young ; and if 

 prevented, around the trunk from the root 

 when old. Some years since, I took a pear 

 tree from a nursery six years old ; its trunk 

 was already trimmed up five feet. I at- 

 tempted to make it grow in the form the 



nurseryman had given it, by cutting off all 

 the sprouts which continually were shoot- 

 ing out from the sides of the artificial trunk. 

 The tree refused to grow vigorously up- 

 ward under the best care, and finally gave 

 evident symptoms of paralysis in the top, 

 by the stunted, short, knotty shoots it would 

 make there every year, while still it would 

 throw out the most vigorous sort of shoots 

 from the side of the trunk. I suspected 

 the cause, and allowed the shoots on the 

 trunk to grow on it, and on all my other 

 trees which were inclining to the same con- 

 dition. In less than two years, they cover- 

 ed their entire trunks with limbs quite to 

 the ground, and then started into a vigor- 

 ous growth throughout the whole top, which 

 they have continued to this time, and are 

 now loaded with fruit. Now mark; the 

 nurseryman, from whom I bought these 

 trees, set out a large number in his own 

 orchard the same spring, and continued his 

 practice of trimming the bodies until the 

 year of the pear-blight, (in 1844, I think,) 

 when every one of his trees were killed to 

 the ground, while not one of mine was in- 

 jured, except a single tree on one side, 

 which had for some reason refused to throw 

 out its side limbs. The same season de- 

 stroyed more than nine-tenths of all the 

 pruned pear trees in the county, while my 

 own yard, and one other in w'hich no 

 pruning had been allowed, were the only 

 ones, so far as I know, which escaped. 



At the time I began to allow the branches 

 to grow on the above named tree, the trunk, 

 just below the upper branches, measured 

 nine inches round ; all the branches to- 

 gether, just above, measured seventeen 

 inches round. Hence, the surface for the 

 return sap was, at the crotch of the tree, 

 five feet from the ground, suddenly con- 

 tracted in something near the ratio of seven- 

 teen to nine, while the passage of the as- 



