This section is from "The Horticulturist, And Journal Of Rural Art And Rural Taste", by P. Barry, A. J. Downing, J. Jay Smith, Peter B. Mead, F. W. Woodward, Henry T. Williams. Also available from Amazon: Horticulturist and Journal of Rural Art and Rural Taste.
We are gradually progressing and yearly learning to better and better understand our climates and soils, our trees and vines; and as we progress and come to know our own, we throw away much of the early-day teachings that were brought to us from across the broad ocean. Our vine-growers commencing with their vines at three to four feet, have gradually expanded them, until now the majority of planters give to them eight by ten or ten by twelve, and some even more, according to the soil and the habit of the sort. So, also, beginning with severe winter and summer pruning, from which they obtained a little fruit, sun-burnt and half ripened, and produced various diseases in the system of the vine, they have come to a knowledge of the vine's nature, and by almost leaving it alone are rewarded with luscious fruit and healthy foliage. In the apple and pear orchard we have been brought to place the first from thirty-five to forty feet apart, and the latter twenty-five to thirty, thus subjecting them to all the terrible burning heat of the sun's rays, in a long, hot summer's drought, and to stand as it were alone, and brave singly the storms of wind that winter and spring bend their tops, and crack and tear loose by leverage their roots.
We have long been impressed with the view that these old advices of distance were erroneous, and our readers will bear us witness that we have before now advised a closer planting; and as a break, also, and aid toward shielding our fruit-trees, the intermingling more or less in the orchard of evergreens.
Our own practice has been most successful in apple orchards at twelve by sixteen feet, and we have known the best results from a like distance by some extensive orchardists in the West. The past two years we have doubted if even this distance had not better be reduced, and in exposed, bleak, wintry situations, on prairies or bluffs, we are satisfied it had. The closer trees are planted to each other, the more do they assist each other in breaking the force of the wind, and in gradually ameliorating the climate. They will sooner shield and shade the ground and their roots; retaining thereby a greater relative proportion of moisture and food, they will come sooner into maturing and fruiting their blossoms; and as they increase in size will acquire the rough bark that comes with maturity and belongs to them in health, so that as they become too thick for the light to keep them round and full in the contour and extension of branch, they will be the better enabled to stand alone, while the fruit that has been gathered from the trees requiring removal will be found to have more than repaid the first cost of the whole orchard.
Were we to plant an apple orchard today, we think we should set our trees ten by fifteen feet, and if of standard pears ten by ten feet, if of dwarf pears or apples six by eight feet, and we would use occasionally an evergreen tree of some hardy variety in the place of a fruit-tree.