This section is from the book "The Gardener's Monthly And Horticulturist V24", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
Does the tapping of maple trees in spring do them any injury? The general opinion will be, yes. It has always been mine. But I wish to state a somewhat singular instance to which my attention has been called. It is that of two groves of maples, planted at the same time alongside of each other, and in every way holding the same position and treatment; one has been tapped for seven successive years, yet the trees show as if they were that number of years larger in size with an equal appearance of health ; the other grove has never been tapped. Another is a grape vine neglected to be pruned in the fall, but was done in the spring. That grape, although it bled profusely, yielded larger and better grapes than it ever did before, and better than any growing alongside of it. This would indicate that tapping maples, and spring pruning of the grape, did not in any way injure them, but rather the reverse. The insertion of this in your paper might throw some light on this subject, and bring out some new ideas on spring pruning.
[At a recent meeting of the Pennsylvania State Board of Agriculture, held at Allentown, the subject of maple sugar making was discussed by several intelligent members of the Board, and the general sentiment seemed to be that there was no serious injury to the trees from the tapping for some years, though some thought there was an injury in time. - Ed. G. M].