A resurvey, made under the direction of Mr. E. L. Demmon of the Southern staff, of portions of the companie's holdings cut over an average of twenty years ago shows that from areas cut to a fourteen-inch diameter limit about 10,600 board feet, Doyle Scale, were removed, and on other areas, where the plan of conservative logging was not followed and cutting was to a 10-inch limit, about 11,800 board feet. The original stand on the two areas was nearly the same. The more conservative cutting left 712 feet per acre by the Doyle Scale, which gave no volume to any tree below 10-inches in diameter, 4 feet from the ground; the heavier cutting practically gutted the land, leaving but 84 feet per acre. Twenty years later the 712 feet on the 14-inch limit cutting had increased to 1665 feet. Using in place of the Doyle a scale which reflects pretty accurately the number of board feet that may actually be sawed out of the trees, we found 3132 feet standing on the average acre. Twenty years, in spite of repeated fires, had increased the 84 feet on the 10-inch limit cutting ten-fold, or to 883 feet, 2046 feet is the estimate of what may actually be sawed out today.

More encouraging than these per acre figures, and probably more useful to any one interested in applying a diameter limit to his own timber, is the data obtained on growth of individual trees. It has not been practicable so far to separate the 318 trees measured for growth into classes which reflect the degree of release, that is, which correspond to certain distances to which competing trees were removed. However, we did find that unless the trees cut stood within thirty feet of one left standing, the standing tree continued to grow at the old rate; in other words, its growth was not stimulated by the removal of the others. Since 48 trees can stand evenly spaced 30 feet apart on an acre, and since about 55 pine one inch in diameter remained on the average acre after cutting, it will be clear to any one familiar with the irregular spacing characteristic of the Southern pines that not all of the trees, by any means, were released. Nevertheless, the average tree was greatly stimulated, the small more than the large. Growth in diameter for the 10 years before cutting had been very uniform-from .85 to 95 inches, or about 22 rings to the inchfor all sizes of trees. For an average of two years after cutting the trees grew at the old rate. But in 8 years more, or a total of 10 years following cutting, 4-inch trees (4 inches at time of cutting) had grown 21⁄2 inches; 6-inch tree 2 inches; 8-inch trees 134 inches; and so on tapering down to a little over an inch of growth in 17-inch trees, which therefore grew only

duction. Good natural reproduction, we are convinced, can be secured by a rather limited number of mature trees for seed. The Southeast is not obliged to resort to very careful partial cuttings in order to be sure of natural reforestation, as is apparently true in the Western yellow pine forests. It is the rate of growth of the released trees that will determine the usefulness of this method of cutting to the producer of Southern pine. This rate of growth, unlike the rate of growth of even-aged stands, cannot well be expressed in tables for general use. The Southern Forest Experiment Station, in cooperation with the National Research Council and the State Foresters of the South, it is only now completing a fiveyear study of the rate of growth of Southern pines in even-aged, fully stocked, second growth stands. We will shortly publish tables showing how many cords of wood or board feet of lumber may be expected at any given age from second-growth trees which, starting all at one time, are neither in too crowded nor too open stand, and are, therefore, producing wood at the maximum rate per acre. The growth of trees in allaged stands, such as are produced by diameter limit cuttings, is much harder to predict, because it varies with the diameter limit used and with the proportion of the stand which is removed. It of course varies also with the species of trees and the combination of soil and climate which we foresters for convenience call "site;" these variables are encountered in the study of even-aged growth also. The Southern Station is by no means ready to make detailed predictions of the growth of our pines following diameter limit cuttings, because it is only on the threshold of the necessary studies, but I am glad to be able to give you the significant results of our recent study of one particular tract.

Results On Kau! Tract

In 1902 the Kaul Lumber Company, of Birmingham, Alabama, asked the United States Forest Service to examine its longleaf pine forests in north central Alabama, and to inform it of the probable results from various degrees of cutting. The company was not then particularly hopeful of keeping fire out of the cut-over lands and obtaining thereby a crop of young trees to take the place of those removed. It did want to know what growth could be expected if no trees below a specified size were cut. As earlier remarked, rigid observance of a diameter limit is not first-class forestry, but in view of the very general indifference of Southern lumbermen to forestry at that time the Kaul Company deserves considerable credit for applying even-a crude system of scientific practice to its cuttings of 20 years ago.

A resurvey, made under the direction of Mr. E. L. Demmon of the Southern staff, of portions of the companie's holdings cut over an average of twenty years ago shows that from areas cut to a fourteen-inch diameter limit about 10,600 board feet, Doyle Scale, were removed, and on other areas, where the plan of conservative logging was not followed and cutting was to a 10-inch limit, about 11,800 board feet. The original stand on the two areas was nearly the same. The more conservative cutting left 712 feet per acre by the Doyle Scale, which gave no volume to any tree below 10-inches in diameter, 41⁄2 feet from the ground; the heavier cutting practically gutted the land, leaving but 84 feet per acre. Twenty years later the 712 feet on the 14-inch limit cutting had increased to 1665 feet. Using in place of the Doyle a scale which reflects pretty accurately the number of board feet that may actually be sawed out of the trees, we found 3132 feet standing on the average acre. Twenty years, in spite of repeated fires, had increased the 84 feet on the 10-inch limit cutting ten-fold, or to 883 feet, 2046 feet is the estimate of what may actually be sawed out today.

More encouraging than these per acre figures, and probably more useful to any one interested in applying a diameter limit to his own timber, is the data obtained on growth of individual trees. It has not been practicable so far to separate the 318 trees measured for growth into classes which reflect the degree of release, that is, which correspond to certain distances to which competing trees were removed. However, we did find that unless the trees cut stood within thirty feet of one left standing, the standing tree continued to grow at the old rate; in other words, its growth was not stimulated by the removal of the others. Since 48 trees can stand evenly spaced 30 feet apart on an acre, and since about 55 pine one inch in diameter remained on the average acre after cutting, it will be clear to any one familiar with the irregular spacing characteristic of the Southern pines that not all of the trees, by any means, were released. Nevertheless, the average tree was greatly stimulated, the small more than the large. Growth in diameter for the 10 years before cutting had been very uniform-from .85 to 95 inches, or about 22 rings to the inchfor all sizes of trees. For an average of two years after cutting the trees grew at the old rate. But in 8 years more, or a total of 10 years following cutting, 4-inch trees (4 inches at time of cutting) had grown 21⁄2 inches; 6-inch tree 2 inches; 8-inch trees 134 inches; and so on tapering down to a little over an inch of growth in 17-inch trees, which therefore grew only

about 20 per cent faster as a result of cutting, as contrasted with 168 per cent faster in the case of four-inch trees.

For convenience and ease of comprehension we have put on the wall chart the figures just given, and further data showing the growth of the various sizes of trees in twenty years following cutting. Summarized, the information is this: trees at 4 inches at time of cutting grew five inches in twenty years; 6 inch trees, 4 inches: 8 inch, 31⁄2 inches; and so on down to 2 inches of growth on 17 inch trees. We have also worked out volume increases in cubic and board feet, but I will not present them here. It is enough to say that 14 inch trees, for example, which averaged 100 years old at the time of cutting, increased nearly 50 per cent in board foot volume in the twenty years following cutting.

The growth figures for the Kaul tract may or may not be applicable to any other tract. Had the diameter limit been different, a greater or less proportion of the stand would have been cut, and the remaining trees would have been released to a greater or less degree. One thing is certain that a more flexible application of the limit would have given better results. From the trees on this tract and on many others the figures from which the Southern Station is now analysing, we are certain that trees in groups must be thinned out before anything like a uniform stimulation of growth can be expected. Again, it is self-evident that diseased, spike-topped, or otherwise handicapped trees are not worth leaving for future growth, and should be taken in the first cut if merchantable. Since the longleaf pine in north central Alabama is at the extreme of its northern range in that state, we feel reasonably confident that response of longleaf pine to a diameter limit cutting there would not be greater than well within the tree's range. This, and the fact that the limit was mechanically applied make us regard the rates of increased growth as conservative.

Diameter Limit In Second Growth

Applied to a second-growth forest, such as the typical old-field stands of this state and North Carolina, a diameter limit cutting would again give different results, and probably poorer ones. This is because most second growth is even-aged. That is, unless the second-growth comes up rather raggedly, crouding forces the struggling young trees to drop their lower Imibs early, and if only the larger trees were cut from such stands the remainder might have so few live limbs as to be unable to respond promptly and vigorously to the sudden increase in light above, and of soil moisture below. If cut for cordwood or pulpwood, and therefore

before the full effect of the crowding was reflected in shortened crowns, these stands would do better under a diameter limit cutting than if developed for saw-logs. Diameter limits applied to young stands would result in something resembling a thinning by the French, as opposed to the commoner German, system. A year ago the Southern Station established some long term studies of cutting young stands to a diameter limit, and of real thinnings by the French system.

Whether the sum total of wood produced, if a forest is cut continuously to a diameter limit, is greater than if it is cut clean at intervals and reproduced to an even-aged stand is a question which far over-taxes our present knowledge. The chances are that the amount of wood fibre grown is the same in both cases. In all-aged forest which results from repeated diameter limit cuttings the wood yearly produced is distributed as a comparatively thin layer over a very large number of trees of all sizes and degrees of merchantibility. In the even-aged forest which results from clear-cutting, the same amount of wood is distributed as a thicker layer on a much smaller number of trees, at least after the first few years. The latter distribution results in a larger amount of merchantable volume becoming available for cutting at such a time as any trees at all have reached cordwood or saw-log size, but before that in a complete lack of merchantable trees. Under a diameter limit system there are always some trees of usable size, and the quality of the wood is higher for many purposes, because of its finer grain. The arguments pro and con might be spun out indefinately, to no purpose except to induce sleep on your part.

No Practical Obstacles

The practicability of diameter limit cuttings I can discuss very briefly, because after all it is a matter which each lumberman or landowner must figure out for himself. But taking the Southern piney woods as a whole, it is safe to say that no broad condition prevents the use of a diameter limit in cutting. We do not have generally in the South the logging difficulties which in some regions compel clean cuttings at long intervals in place of partial cuttings at short intervals. Unless it be in swamps like the Dismal and Okeefinokee and a few hilly regions such as occur sparingly in every Southern state, pine timber is accessible and easy to log. Stands averaging several thousand feet to the acre are heavy enough to allow of partial cutting. The cuts and fills of old logging trams remain in astonishingly good shape for years, in spite of the 50 inches of yearly rain which makes our Southern forests grow so