134 



VITALITY AND LONGEVITY IN FRUIT TREES. 



'ultirnate cause of the final catastrophe, as 

 some think in other parts of the country ii 

 is, it is still obvious how in that case this 

 high culture should hasten the final catas- 

 trophe In that case, there would be an 

 artificial excess of return sap in the stem, 

 unprotected from the cold, just as in the 

 other case the same plethora is unprotected 

 from the heat. 



The case of the scions alluded to above, 

 in connexion with all other facts, convinces 

 me that all our blight here is produced, in 

 fact, by the hot sun in summer, though not 

 generally developed to the eye until severe 

 cold occurs in winter, or perhaps not until 

 the ensuing spring or summer. That cold 

 may produce similar effects elsewhere, is 

 perhaps both natural and probable; but I 

 have never seen it. 



The PROXIMATE CAUSE, then, of blight 

 here, both in the apple and the pear, is the 

 effects of the hot sun upon the unprotected 

 trunk and branches of the tree, while the 

 return sap is in an unnatural condition of 

 plethora. It is not unlike, either in its 

 predisposing or proximate causes, to the 

 disease familiarly known in the west by the 

 name of sun-stroke, in the human system. 



The PREDISPOSING CAUSES are, first, a 

 general hereditary debility of those kinds 

 of trees that have been through several 

 generations, propagated without bringing 

 them in contact with the vital energies of 

 healthful seedling roots ; and toward the 

 same results the apple is fast tending in 

 these parts, and probably wherever the 

 same absurd mode of grafting is practiced 

 upon a rich soil, and under a hot sun. 



Second, the interference in pruning, in 

 interrupting the general healthful functions 

 of the tree, and particularly in violently 

 disturbing the natural and necessary equi- 

 librium between the capacities of the tree 

 for transferring its ascending and descend- 



ing currents of sap; this latter point de- 

 serves to be presented more in detail, both 

 in its philosophy and in the nature and ex- 

 tent of diseases it is liable to produce, both 

 in the bark and in the trunk, and finally in 

 the top. But I cannot tax your patience or 

 that of your readers further on the sub- 

 ject at present. Meantime, I apprehend 

 that it will be found, at last, that the term 

 "fire-blight," or "frozen sap-blight," is not 

 a specific name, but only a general term, 

 to signify analogous modes of disease, 

 arising from the same predisposing causes, 

 but developed by a variety of proxima,te 

 causes, like fever in the human subject ; 

 and that while we may postpone the catas-- 

 trophe in single cases by attention to soil 

 and culture, we shall never get rid of the 

 constitutional tendency and latent debility 

 of the predisposing causes, until we study 

 the nature of trees more, and apply the na- 

 ture of the knife and the saw less, until, 

 in a word, both in grafting and pruning, we 

 learn how to interfere with nature as little 

 as possible. I went last winter to see an 

 apple orchard some forty miles distant, be- 

 longing to a man too old and too lazy to 

 touch it with a knife or saw. At first view, 

 it looked horribly. The trees were all 

 bushes, or rather thickets, having all the 

 shoots of fifteen or twenty years' growth 

 standing on and around the trunk, or what 

 was originally intended for the trunk of the 

 tree. Yet this orchard was overloaded, in 

 all its tangled branches and clusters of 

 sprouts, last year with fine fruit; and is the 

 only one I have ever seen in the state, of the 

 same age, that had not a single tree affected 

 with the sun-stroke, as I have called it, or 

 frozen sap-blight, if you please. 



Doubtless, in some cases, these several 

 causes produce their effects — each without 

 the aid of the other; but so far as I have 

 noticed, where the three coexist, speedy and 



