This section is from the book "The Gardener's Monthly And Horticulturist V23", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
By A. des Cars. Translated from the French by Prof. Charles S. Sargent. Boston: A. Williams & Co.
Professor Sargent has done a very useful work in presenting to American readers this standard work. It affords them the opportunity of knowing all that is best in the practices and speculations of European foresters.
Taking this as an exposition, the perfection of forestry pruning art in the old world, we cannot but feel that when forestry shall be an art in our country, we will far exceed Europe in our results. Trees grow slowly there in comparison with what they do here, and the laws of pruning require different application.
The main principle, as taught in this book, is undoubtedly correct, that by judicious pruning in connection with skillful management, we may often double the value of a tree in the same time; and, if any attempts be made in Forestry on a large scale in our country, something more than merely setting out the trees will be required to make forestry pay. Take for instance a forest of Catalpas. The seedling plant may grow from two to four feet the first season, but always a portion of this first year's growth dies back. The result is that many side sprouts come out and a crooked leader ensues. The next year the growth is very strong, but usually the terminal growth is killed in the second year also, and another crook is formed in the leader. The third and succeeding year the growth does not die back. We know the reason of this in our country. We know that these branches die from evaporation of their juices, and that when the roots are strong and deep, so as to provide for this evaporation the wood does not die. Under these circumstances the correct system of pruning is that which looks to the strengthening of the roots as soon as possible.
To this end the forester would let the plant grow just as it wants; to for a couple of years, provided it should produce as many large healthy leaves as possible. It is the number of healthy leaves that make large, strong roots. When these roots have be-come strong - at the end of two seasons' growth - the young plant is cut to the ground, and all but one sprout left to grow. Then we may get a strong straight stem, eight or ten feet in one season, and which, keeping its leading bud, will go on and make a straight, clean trunk, which is essential in a good timber tree. European works teach us nothing of this. They know scarcely anything of the laws of evaporation in connection with growth and hardiness. To this day the thermometer is their only guide in judging of the ability of a tree to withstand frosts. They have little chance to learn further, for in their moist climate evaporation need not enter into profit or loss account. Even in the ordinary laws of vegetable physiology as applicable to forestry, their leading authors at least are far behind. Old exploded notions are still made the basis of practical work.
We read here as we read fifty years ago that "sap mounts from the roots to the leaves, and then returns in an elaborated condition to the roots." In America the transpiration of the leaves is enormous. The evaporation of moisture is believed to be about equal to the ability of the roots to absorb. There is no necessity for any return of moisture to the roots. That carbon is returned to the roots, and perhaps other material used in feeding the cells comes in downward direction is true, but this is just as likely to travel downwards in a gaseous as in a liquid state. We refer to this point chiefly to show how little part the transpiration of moisture plays in any system of European forest pruning, but which must be taken note of by the American forester.
Our author tells us further that "certain theorists declare that there is an absolute correlation between the roots and the branches of a tree, and the cutting off of a branch necessarily kills the corresponding root. If such a theory is correct how can the results obtained by cutting back young trees to the ground, or the topping of pollards, by which all the branches are suppressed, be explained?" We fancy no person of any note believes that every root has each its set of leaves which feed it, - but it is no "theory," it is an absolute fact, that roots do die just in proportion as the top is cut away. The reason why trees push up strong when cut back (as in the young Catalpa for instance) depends on other matters not generally perceived by European pruners, though quite familiar to American gardeners.
These criticisms are offered merely to show the necessity for a purely American school of forestry. Of the little work itself, and its many practical hints and suggestions, we have nothing but praise. Not merely the forester, but the grower of a few fine specimen trees will profit by it.