L MISC. PUBLICATION 217, U. S. DEPT. OF AGRICULTURE 



make up each region in the United States, Alaska, Puerto Eico, and 

 Hawaii. 



This publication is intended to help people get better acquainted 

 with trees and forests. It should lead to a broader appreciation of 

 the value and importance of trees and result in greater care of our 

 forests and their better protection against fire. This in turn should 

 mean a larger measure of out-of-door pleasure and profitable recreation. 



NATURAL GROUPS OF FOREST TREES 



The cone-bearing trees, such as the pines, spruces, firs, cedars, and 

 cypresses, are commonly grouped together and known as conifers or 

 from a lumber standpoint as softwoods. The other group is known 

 as hardwoods and consists of the broadleaf trees, such as the oaks, 

 elms, ashes, maples, and hickories. These two groups are now 

 widely recognized, and they are generally true to name. In each 

 group, however, the woods differ widely in hardness as well as weight 

 and strength, and some exceptions occur. For example, the long- 

 leaf pine among the conifers or softwoods has wood that is harder 

 than that of willow and magnolia which belong to the hardwood group. 

 In the group of hardwood trees occur two subgroups or families, 

 namely the palms and yuccas, whose wood and seed structure are 

 very different from all the others. Still another strange family 

 among the hardwoods is the cactus. Further reference to all of these 

 natural groups from a botanical standpoint will be found under the 

 next heading. 



Another natural grouping separates the evergreen trees from the 

 deciduous trees, or those that drop their leaves in the fall. Most of 

 the conifers, such as the pines, junipers, firs, and spruces, are ever- 

 green in habit, that is, they hold their leaves over winter. The larches 

 and southern cypress, however, drop their leaves in the fall and are 

 thus deciduous, like most of the northern hardwoods. The holly, a 

 southern hardwood which extends into the North, is evergreen. In 

 the southern portion of the United States many hardwood trees are 

 evergreen and shed their leaves only after the first, second, or third 

 years. Among these are five and laurel oaks, red bay, evergreen 

 magnolia, laurel cherry, and many small trees of the subtropical and 

 tropical portions of Florida and Texas and parts of New Mexico, 

 Arizona, and California. 



NATIVE TREES IN GREAT VARIETY 



The forests of the United States are composed of a large number of 

 different kinds or species of trees, many of which are of high usefulness 

 and value. Probably no other land of equal area lying within the 

 Temperate Zones has so many different tree species with so great a 

 variety of woods as this country. 



The botanical classification of trees is at the best somewhat com- 

 plicated. An attempt is here made to show in a simple way the 

 botanical grouping of our native forest trees. 2 



The forests of continental United States are composed of a total 

 of 810 different kinds or species of native trees, 3 grouped under 199 



2 Only native trees will be considered in this publication. This excludes all foreign or exotic trees, many 

 of which are com m only present and often included in popular descriptions. 



3 There are many recognized varieties and hybrids, but they are not generally included in this publica- 

 tion. Only a few varieties of unusual importance are mentioned, together with a few that are the sole repre- 

 sentatives of the species. 



