io 9 



FOREST TYPES OF THE UNITED STATES 



WILLIAM A. DAYTON 



Because of the size of the United 

 States, the diversity of its conditions, 

 and the wealth of its vegetation (we 

 have about four times as many tree spe- 

 cies as does Europe) and because of 

 differences in terminology and of opin- 

 ions on classification, climaxes, and 

 such, it is not surprising that ideas 

 about the forest types of the United 

 States are still somewhat controversial. 



Dr. James Graham Cooper (1830 

 1902), Army surgeon, explorer, and 

 naturalist, seems to have been the first 

 to publish a vegetative- type map of 

 North America. It appeared in 1859 in 

 his paper On the Distribution of the 

 Forests and Trees of North America, 

 with Notes on its Physical Geography. 

 Overleaf is reproduced the United 

 States part of Dr. Cooper's map; the 

 original letters for his regions are re- 

 tained, but hachures have been added 

 to make their differentiation clearer to 

 the eye. It will be observed that four of 

 Dr. Cooper's regions are in the Eastern 

 seaboard, three are in the Appalach- 

 ians, six are in the Plains States, five 

 are in the Rocky Mountain areas, three 

 are in the Intermountain area, and two 

 on the Pacific coast. Most of them are 

 forested areas, at least in part. 



Dr. Cooper was a link between an- 

 cient students of the subject and the 

 modern investigators, who have added 

 a great deal to our ken of botany. 



Theophrastus of Eresus (372-287 

 B. C.) by the will of Aristotle became 

 heir to the great philosopher's cele- 

 brated library, guardian of his chil- 

 dren, and his successor as head of the 

 Lyceum at Athens. Theophrastus has 

 been called "primus verorum botani- 

 corum" the first real botanist. He 

 was perhaps the first to emphasize the 

 relation of trees and other plants to 

 their environment, and may rightly be 

 regarded as the father of the concepts 

 of ecological and vegetative types. 



Nearly two centuries ago, Linnaeus, 



in his Philosophia Botanica, had a 

 chapter on plant distribution corre- 

 lated with the geographic regions, cli- 

 mate, soils, and the other factors of 

 habitat. 



Henry Solon Graves, who published 

 Practical Forestry in the Adirondacks 

 in 1899, is generally credited with the 

 introduction of the term "forest type" 

 in this country. The late Dr. Frederic 

 E. Clements, a distinguished ecologist 

 and author of Plant Formations and 

 Forest Types, published in 1909, calls 

 Professor Graves' types "plant (or 

 forest) formations." He separates for- 

 mations into associations, associations 

 into societies, societies into communi- 

 ties (with two or more principal or 

 secondary species), and communities 

 into families (defined as groups of co- 

 specific individuals) . 



The Ecological Society of America 

 tentatively suggested this definition 

 of "forest types" in 1934: "A forest 

 stand essentially similar throughout 

 its extent as regards composition 

 and development under essentially sim- 

 ilar conditions, i. e., essentially similar 

 throughout as regards floristic com- 

 position, physiognomy, and ecological 

 structure." 



Ten years later the Committee on 

 Forestry Terminology of the Society of 

 American Foresters defined forest type 

 thus: "A descriptive term used to 

 group stands of similar character as re- 

 gards composition and development 

 due to certain ecological factors, by 

 which they may be differentiated from 

 other groups of stands. The term sug- 

 gests repetition of the same character 

 under similar conditions. A type is 

 temporary if its character is due to 

 passing influences such as logging or 

 fire; permanent if no appreciable 

 change is expected and the character 

 is due to ecological factors alone; 

 climax if it is the ultimate stage of a 

 succession of temporary types. A cover 



