Vol. XXIV December, 1923 No. 288 JOURNAL OF The New York Botanical Garden EDITOR HENRY ALLAN GLEASON Curator CONTENTS Botanical Observations in Northern Michigan 273 Francis Alexander Schilling 28 J Public Lectures during December 284 Notes, News and Comment 284 Accessions 286 Index 291 PRICE $I.OO A YEAR; IO CENTS A COPY PUBLISHED FOR THE GARDEN AT 8 WEST KING STREET, LANCASTER. PA. INTELLIGENCER PRINTING COMPANY OFFIOERS, 1923 PRESIDENT—FREDERIC S. LEE ViCE.PKEsiDENTS|H™TWRDfOREST TREASURER—JOHN L. MERRILL ASSISTANT TREASURER—HENRY DE LA MONTAGNE SECRETARY—N. L. BRITTON 1. ELECTED MANAGERS Term expires January, 1924 N. L. BRITTON LEWIS RUTHERFORD MORRIS HENRY W. DE FOREST FREDERIC R. NEWBOLD W. J. MATHESON W. GILMAN THOMPSON Term expires January, 1925 HENRY DEFOREST BALDWIN ADOLPH LEWISOHN PAUL D. CRAVATH BARRINGTON MOORE JOSEPH P. HENNESSY WILLIAM BOYCE THOMPSON Term expires January, 1926 EDWARD D. ADAMS JOHN L. MERRILL ROBERT W. DEFOREST J. P. MORGAN DANIEL GUGGENHEIM F. K. STURGIS 2. EX-OFFICIO MANAGERS THE MAYOR OF THE CITY OF NEW YORK HON. JOHN F. HYLAN THE PRESIDENT OF THE DEPARTMENT OF PUBLIC PARKS HON. FRANCIS DAWSON GALLATIN 3. SCIENTIFIC DIRECTORS PROF. R. A. HARPER, Chairman DR. NICHOLAS MURRAY BUTLER DR. FREDERIC S. LEE PROF. WILLIAM J. GIES HON. GEORGE J. RYAN PROF. JAMES F. KEMP PROF. HERBERT M. RICHARDS PROF. HENRY H. RUSBY GARDEN STAFF DR. N. L. BRITTON, Director-in-Chief (Development, Administration) DR. MARSHALL A. HOWE, Assistant Director (Administration) DR. JOHN K. SMALL, Head Curator of the Museums (Flowering Plants) DR. W. A. MURRILL, Supervisor of Public Instruction DR. P. A. RYDBERG, Curator (Flowering Plants) DR. H. A. GLEASON, Curator (Flowering Plants) DR. FRED J. SEAVER, Curator (Flowerless Plants) ROBERT S. WILLIAMS, Administrative Assistanl PERCY WILSON, Associate Curator P. DE C. MITCHELL, Associate Curator DR. A. B. STOUT, Director of the Laboratories DR. JOHN HENDLEY BARNHART, Bibliographer KENNETH R. BOYNTON, Head Gardener SARAH H. HARLOW, Librarian DR. H. H. RUSBY, Honorary Curator of the Economic Collections ELIZABETH G. BRITTON, Honorary Curator of Mosses DR. ARTHUR HOLLICK, Paleobotanist DR. H. M. DENSLOW, Honorary Custodian WALTER CHARLES, Museum Custodian JOHN R. BRINLEY, Landscape Engineer WALTER S. GROESBECK, Clerk and Accountant ARTHUR J. CORBETT, Superintendent of Buildings and Grounds JOURNAL OF The New York Botanical Garden Vol. XXIV December, 1923 No. 288 BOTANICAL OBSERVATIONS IN NORTHERN MICHIGAN The state of Michigan is characterized by two distinct and important types of vegetation, the hardwood, broad-leaved forest of the central and south-central United States, and the evergreen, needle-leaved forest of the northern states and Canada. The former is predominant in the southern half of the lower peninsula, where the climate is not essentially different from that of the vicinity of New York City. In the northern part of the state the two forest types meet, and here they have for centuries waged a war for supremacy. Ecologists aver that the struggle has slowly but surely turned in favor of the beech, maple, and oak of the southern forest, which have gradually pushed farther and farther to the north, while the pine, spruce, and fir of the northern forest have steadily retreated northward toward Canada. Little evidence of this botanical contest now remains. The armies of both belligerent forests have been sadly decimated by a third and much more powerful force—man, armed with the axe, the circular saw, and the railroad. His onslaught fell first on the extensive forests of white pine and Norway pine, and from 1880 to 1890 millions of feet of lumber were manufactured and shipped. As the pine forests disappeared and the demand for lumber still increased, the beech and maple were similarly at­ tacked . As a result of nearly half a century cf lumbering, almost none of the original magnificent forest is left. The University of Michigan has located its Biological Station on a tract of some three thousand acres of cut-over land, situated on the shores of Douglas Lake and Burt Lake, about fifteen miles south of the Straits of Mackinac. Courses of instruction 274 in botany and zoology have been offered every summer for the past fifteen years, and numerous gradual e students find there excellent opportunities for research in many different lines. Any botanist finds interest in noting the effect of lumbering and fire on the forest vegetation, and soon becomes an ardent con­ servationist, if he was not one before. The pine land is generally poorly adapted to agriculture and has been allowed to stand continuously idle. After lumbering, the land is left a jungle of brush heaps and soon grows up to dense thickets of aspen, birch, and pin cherry, with an almost continuous ground cover of bracken fern. Always enough crooked or partially decayed trees are left standing to seed the cut-over land, so that the development of a new generation of pines begins immediately. Thousands of pine seedlings appear and grow rapidly. Annual increments of three feet are frequent, and the aspen thickets would soon be replaced by young pine forest if it were not for fires. Fires originate through the carelessness of hunters and fishermen, from temporary camps, from attempts of the farmers to clear land, from sparks from locomotives, and doubtless in other ways as well. In any case, they occur somewhere every year and in such dry seasons as the summer of 1923 they become common and widespread. On one day twelve fires were counted in a drive of only seven miles. They are brush fires, feeding on the ground litter and the self- pruned branches of the aspens, but they are hot enough to kill the aspens and the young pines. They favor the germination of aspens, and the following year another generation promptly springs up, while the trees killed by the last fire soon fall to the ground to furnish a new supply of fuel. So the dismal cycle is continued and has continued for years, and doubtless will con­ tinue for years to come, until a better public spirit has developed. Given protection from fire, the young pines continue their rapid growth and replace the aspens at their death. The aspen is a short-lived tree, at least under these circumstances. It may be that the sandy soil is too poor to permit their larger growth, it may be due to their crowding in thickets or to some water relation, but it is evident that most of them die naturally after about twenty-five years, unless killed by fire before that time. On the University property, which has been repeatedly devas­ tated by fires, two small areas have escaped for the past several 275 years. On one of them the last fire was apparently in 1901. There the aspens form a low forest, beneath which fine young pines are growing vigorously. In a few years more the aspens will be dead, and the pines will grow faster with the better light. Possibly ten years will place this area beyond danger from brush fires. On the second, the change from aspen to pine has taken place during the past ten years. The old aspen trees have already decayed and are replaced by a thrifty growth of healthy pines, already beyond danger from the ordinary brush fire. Such natural replacement depends obviously on the presence of old trees for seed. In places where the lumberman's axe or repeated and severe fires have taken all the pines, reforestation will be very slow. In such cases the planting of young pines and their protection for a few years would speedily produce a forest which should be a steady source of revenue. Cut-over pine land has little agricultural value, being composed largely of pure sand, and pine is probably the most profitable crop which it will produce. The lumber companies abandoned it after taking off the lumber, and thousands of acres have reverted to the State for non-payment of taxes. It has been computed that this public land, if properly reforested, would yield enough profit annually to relieve the State of all taxation. Instead it now yields no revenue at all, and in some counties so much land be­ longs to the State that the little taxable land left is barely suf­ ficient to carry the expenses of the local government. Probably no better argument for a vigorous policy of forest conservation and reforestation can be found in the eastern United States than these hundreds of miles of aspen thickets, dreary, monotonous, valueless, but capable of producing millions of feet of the finest quality of white pine lumber. The condition in the hardwood forests is somewhat different. Such forests usually occupy a better type of soil, with fair or good agricultural possibilities. There is of course little reason for using such land for forest if a greater revenue can be obtained from agriculture. But the hardwood forest, as well as the pine, does need some sort of protection from an esthetic, scientific, and historical standpoint. Michigan's forests made her famous and wealthy, and were the foundation on which scores of private fortunes were built. If Mackinac Island deserves protection for its historic interest, or the Yosemite for its beauty, or the bison 276 for its scientific interest, surely the Michigan forests are equally deserving. The destruction of a forest means far more than the removal of the trees. It also means the immediate extinction, for that locality, of numerous other plants and animals. The coral-root, the rattlesnake plantain, the arbutus, and many other wild flowers of charm and interest; the salamander, the raccoon, the pileated woodpecker, and numerous other animals disappear.