A. J. Downing, Esq

I have heretofore suggested to yon my design of offering through the medium of your columns, to the pomological world, the outline of a rude theory which I have entertained for some years, respecting the existence of two forces or principles in vegetable physiology, and their bearing upon the science of culture, training, and pruning. It has seemed to me that the vague, indistinct, not to say contradictory notions of these forces, to be learned in the books, is a frequent source of injury to the cause of fruit culture at large.

In order to explain the nature of the two forces referred to, and in order to give an example of the manner in which erroneous views of their nature may operate, I shall quote a few authorities setting forth the axiomatic and doctrinal nature of said forces, according to the present state of the science of vegetable physiology.

Four of the best American authors, Downing, Thomas, Barry and Ken rick, and at least one English writer, Loudon, agree substantially in setting down to the account of over luxuriance, the cause of unfruitfulness in trees of the orchard or fruit garden - as also in stating that fruitfulness lies in an opposite direction, or at some point towards feebleness not more remote than debility itself. Downing asserts that fruit fulness-or luxuriance, or rather the causes which lead to their development, are susceptible of being excited, either the one or the other, at the will of the operator, by "difference in the mode of pruning." The others make luxuriant wood growth and fruitfulness two antagonistic extremes, stating in substance that "whatever tends to promote one retards the other." These, and such other of the best authors as I am familiar with, all admit an existence of two tendencies in the condition of a tree, one to fruit-bearing, and one to the making of wood-branches; all agree that fruitfulness lies in an opposite condition from wood formation, but in terms so general that the inexperienced are left to infer that the farther you recede from luxuriance, the nearer one approaches the point of fruitfulness.

In fine, high feeeding, in one form or other, is set down as the great agent for exciting the system of wood-buds and starvation, for bringing into activity the fruit bud. Luxuriance and unfruitfulness are used as synonymous terms, and by inference, starvation and fruitfulness seem also to have the same import. My theory of these forces supposes them also to exist in a state of antagonism - that the seat of the wood system is in the trunk, branches and roots, between which there is evidence of a strong sympathy, and of a continued action and reaction - that the fruit-bearing system has no sympathy with the roots, but feeds upon the juices of circulation in the branches, as parasitical plants - that fruit spurs once developed never change their nature, except in consequence of some act of violence, and may multiply like parasitical plants, until their demand upon the juices of circulation even starve out the wood-buds, and finally induce the death of the tree. Fruitfulness I consider a state of normal health in a tree large enough to bear.

I think it exhibits the existence of these two forces in a state of equilibrium, and a departure therefrom, towards either extreme - towards luxuriance or feebleness, is a disturbance of the balance of power - the beginning of a state of disease, the nature of which will entirely depend upon the character of the force in predominance, and must call for remedies in accordance; that is, a tree too luxuriant for fruitfulness will need depletions, while a starving subject would want stimulants and tonics.

In giving an example of the manner in which erroneous notions of these forces affect the cultivator, I will suppose one has, as a subject, a tree unfruitful from too great luxuriance. Suppose he should undertake to cure this defect by lessening the number of rootlets catering for the woody system, by root pruning, would it not be absurd philosophy and a waste of time to fill up with rich manures, a trench made for amputating the roots thus enabling the surviving rootlets to gather from a crib, food in quantities, perhaps, equal to the efforts of the whole system from leaner pastures before amputation.

Again, a tree neither too feeble nor too luxuriant for fruit-bearing, ought not to be pruned unless for symmetry's sake - whilst one needing the knife ought to be considered either as too rigorous or too feeble. How confused, then, must the science of pruning be, when its best expounders direct an annual indiscriminate pruning of trees under all conditions, when the admitted effect of that particular mode of pruning too, is to stimulate but one of these forces. Yet such cases are in the books, and one of these cases I will refer to, because the distinguished author who exercises, and I think justly exercises a wide-spread influence over many admiring friends, has in the south and west led some of them into error and disappontment. I would not be understood in this as endeavoring to show off the gentleman's fallibility. I willingly acknowledge myself his debtor for much, both of pleasure and instruction. In fact, I have thought that none other than an inspired member of Pomona's priesthood could have given readings of the laws of nature so generally true to her text-book, as those rendered by the accomplished author of the Fruits and Fruit-Trees of America, and I have thought moreover, that high latitude and New-Jersey sand betrayed him into the error alluded to, which is taking the peach tree at three years old, and in March or April of every year during life, shortening-in the branches.

In any cultivated orchard of the Indian corn district, west or south, this treatment is erroneous. It would be wrong, because in such location the tendency of the tree is, at that age, to over luxuriance, and in that case, cutting off the branches to make it less so, would be as though a farmer should attempt to starve out his briars by cutting off their heads in March, when the roots had before them a years supply, instead of the fated August - when they would be in the midst of famine; it would be as though he should attempt to reduce the condition of grazing cattle, by diminishing the number of his herds, or increasing the extent of his fields, or the luxuriance of their verdure.

Without much confidence that my remarks will have much interest, other than that of novelty, I propose to consider the appreciable evidences and outward marks, peculiar to the wood system and the fruit bearing, respectively.

Next to class the rules for pro wing, training, and pruning in accordance therewith; reviewing also their aptitude, claiming as I do, to be a great admirer of the true and the beautiful in nature - next to the pleasure of weaving fine theories myself, is that of seeing them stript of their flimsiness by others. I should therefore like to be set right in any error perpetrated in the course of these remarks, by any of your numerous correspondents, who shall perceive an error, and at the same time have patience and inclination for the work. Lawrence Young.

Louisville Ky., Oct., 1851.