Mr. George G. Hedgcock, of the United States Bureau of Agriculture, Bureau of Plant Industry, for revision of the text relating to the fungal enemies of the forest, in Chapter VI.
Mr. S. T. Dana and Mr. Burnett Barrows, of the United States Department of Agriculture, Forest Service, for revision of Chapters IV, V, VI, VII, and VIII.
Professor Charles R. Richards, formerly Head of the Manual Training Department of Teachers College, my predecessor as lecturer of the course out of which this book has grown.
Professor M. A. Bigelow, Head of the Department of Botany of Teachers College, for revision of Chapter I, on the Structure of Wood.
Mr. Romeyn B. Hough, of Lowville, N. Y., author of American Woods and Handbook of the Trees of the Northern States and Canada, for suggestions in preparing the maps in Chapter III.
The Forest Service, Washington, D. C., for photographs and maps credited to it, and for permission to reprint the key to the identification of woods which appears in Forest Service Bulletin No. 10, Timber, by Filibert Roth.
The Division of Publications, U. S. Department of Agriculture, for permission to copy illustrations in bulletins.
The Macmillan Company, New York, for permission to reproduce Fig. 86, Portion of the Mycelium of Dry Rot, from Timber and Some of its Diseases, by H. M. Ward.
Mrs. Katharine Golden Bitting, of Lafayette, Indiana, for the photograph of the cross-section of a bud, Figure 5.