14 MISC. PUBLICATION 16 2, TJ. S. DEPT. OE AGRICULTURE 



timber trees, the longleaf and slash pines are highly important as the 

 source of the gum f rom. which turpentine and rosin are manuf actured. 

 Other species found in the pinelands are southern red, turkey, black, 

 post, laurel, and willow oaks ; black gum ; pond, spruce, and sand pines. 



Another tree of commercial importance, found in the southern for- 

 est, is the baldcypress. It grows mostly in the swamps and 

 lowlands and is one of the few coniferous trees that shed their 

 lea ves in the fall (fig. 8, B) . The supply of this species also is gradu- 

 ally dwiñdling after years of heavy cutting. 



Perhaps the most important hardwood tree of the southern forest 

 is sweet gum, or red gum. At one time its wood was considered of 

 little importance because of its tendeney to warp and twist. With 

 the introduction of proper seasoning methods and the diminishing 

 supply of finishing woods, the sweet gum has risen from a position 

 of comparative obscurity to a rank of seventh among all lumber- 

 producing trees (1938) . As a veneer wood, sweet gum leads all other 

 woods in the country and ranks second as a slack-cooperage wood. It 

 also goes into many other producís. 



Both baldcypress and sweet gum are inhabitants of the alluvial 

 bottoms and swamps. Also growing in bottom-land portions of the 

 southern forest región are túpelo and black gums ; water, laurel, live, 

 overcup, Texas red, and swamp white oaks ; yellow poplar ; hickories 

 (including pecan) ; beech; ashes; red and silver maples; cottonwood 

 and willows; elms; syeamore; hackberry; honeylocust; bays; 

 magnolias; spruce pine; and southern white cedar. 



Tropical Forest Región 



The tropical forest región is so small as to be of almost negligible 

 commercial importance. It consists of two fringes of forest along 

 the coast in extreme southern Florida and extreme southern coastal 

 Texas. Its total área is probably not more than 400,000 acres and 

 the density of the forest varíes greatly. Many kinds of hardwoods 

 are found in this región, but most of them are small and bear ever- 

 green leaves and pulpy berries or stone fruit. A few, like the mástic 

 or "wild olive," are of some commercial or economic importance. 

 The mangrove is also valuable because the impenetrable thickets it 

 forms hold the muddy banks, cause new land to be built up, and act 

 as a windbreak against tropical hurricanes. 



The principal trees of the tropical forest región are mangrove, 

 royal and thatcli palms, Florida yew, wild fig, pigeon plum, blolly. 

 wild tamarind, gumbo limbo, poisonwood, inkwood, buttonwood, 

 mástic or wild olive, and Jamaica dogwood (fig. 9). The tropical 

 species in this región are at the northern limits of their natural 

 ranges which include mostly some or all of the West Indies, the 

 Bahamas, Central America, and South America. The trees probably 

 grew from seed washed ashore during storms or distributed by birds. 



ROCKY MOUNTAIN FOREST REGIÓN 



The forests of the Rocky Mountain región oceupy the high eleva- 

 tions of the various ranges of the Rocky Mountain system between 

 the Great Plains and the Sierra Nevada, from México to Canadá. 

 They are broken by many treeless valleys or plateaus. Because of 



