Relation betweeen age and diameter in trees of the primeval northern hardwood forest

TitleRelation betweeen age and diameter in trees of the primeval northern hardwood forest
Publication TypeJournal Article
Year of Publication1930
AuthorsGates FC, Nichols GElwood
JournalJournal of Forestry

The beech-maple-hemlock climax of the so-called northern hardwoods region of the northeastern United States and adjacent Canada is commonly described, among other things, as being an all-aged forest, and this feature is emphasized as an all-important factor in the ability of this forest to perpetuate itself. Certain it is that, in a primeval forest of this type, trees of all sizes are well represented, from mature and overmature veterans down through progressively smaller sizes to specimens but a few inches tall, with the smaller trees as a rule far out-numbering the larger ones. The natural inference drawn from this condition has usually been that the observed differences in tree size were correlated with corresponding differences in age. Published figures in support of this inference, however, would seem to be mostly lacking, and there are those who would urge that the observed facts by no means warrant such a conclusion. In support of this latter contention may be pointed out such known facts as these: That trees of the same age may differ greatly in size, when grown under different conditions of moisture and light; that the appearance of youthfulness in trees growing suppressed under a forest canopy is commonly misleading; that in second-growth stands which exhibit a marked diversity of size classes all of the trees may be found, upon cutting, to belong to the same age class; that the second-growth forest which develops after a selective cutting of the original primeval forest may prove, upon cutting to be made up very largely of trees which are approximately even-aged. An opportunity to secure some age figures for the northern hardwoods forest has been presented during the past two summers in connection with the removal of a large stand of primeval beech-maple-hemlock forest situated west of Pellston, Michigan--one of the last few remnants of the climax forest which formerly covered a large portion of the northern half of the lower peninsula of Michigan. During the summer of 1928 the plant ecology class at UMBS made a thorough series of ring counts and diameter measurements on about 175 stumps, mostly sugar maple (Acer saccharum), distributed over an area of about 80 acres, near the center of this tract. The stumps examined were practically all more than 8 inches in diameter at the cut surface, since the cutting had been selective, most of the trees below this size being left for purposes of reproduction. In order to complete the study, permission was secured from Mr. W. K. Jackson, president of the Jackson & Tindle Lumber Company, to cut a representative series of the smaller-sized trees, and this work was carried out by the ecology class during the summer of 1929. At this time measurements and ring counts were made of about 185 trees of all sizes, mostly hemlock (Tsuga canadensis), distributed over an area of about 60 acres, adjoining the first area studied. The figures secured during both seasons, for sugar maple and hemlock, are presented in the accompanying tables. The height of the cut stumps above the ground ranged from 2 to 3 feet for the larger, "lumbered" specimens, and 6 to 12 inches for the smaller specimens cut by the class. For the area studied, these facts seem self-evident: (1) That the forest comprises a goodly representation of trees of all ages; and (2) that, in general, there is an approximate correlation between diameter and age among the constituent trees. Without doubt, similar studies of the maple-beech-hemlock climax have been made elsewhere, and it is to be hoped that the results of some of these may find their way into print.