Plant Industries and Climatic Plant Formations 349 



manufacturing purposes. Furthermore, there are large areas 

 of fertile soil that make agriculture profitable. Consequently 

 it has become the region of the densest population of the United 

 States. 



The trees of the deciduous forest region are commonly known 

 as '' hardwoods." Oaks, maples, hickories, elms, ashes, chest- 

 nut, beech, sycamore, cherry, walnut, birch, basswood, and tu- 

 lip constitute the important economic species. In consequence 

 of the variety of products derivable from these hardwoods, these 

 forests have been largely cut over, except on the more remote 

 mountain slopes of the Appalachian system. 



The oaks have furnished railroad ties and heavy beams for 

 wooden structures. Oak is also used in large quantities, together 

 with maple, birch, and w^alnut, in the manufacture of furniture. 

 Nearness of supply led to the establishment of the center of the 

 furniture industry in Michigan, New York, and Pennsylvania. 

 Chestnut wood and bark and chestnut-oak bark have been most 

 important sources of tannin in this region. Hickory, because of 

 its great strength, is used for the handles of tools ; and ash is 

 important in the manufacture of vehicles. 



Elm, beech, maple, chestnut, and birch furnish much of the 

 material for staves in the manufacture of slack barrels for the 

 shipment of cement, flour, sugar, apples, vegetables, and many 

 other commodities. Elm also is the best wood for making the 

 hoops of these barrels, because of its toughness and tensile strength. 

 For tight cooperage — that is, barrels for the storage and ship- 

 ment of liquids — white oak is the wood most desired. Cotton- 

 wood is one of the leading sources of excelsior and " wood wool " 

 used for packing and for filling for mattresses and upholstery. 



The making of syrup and sugar from the sugar maple was prac- 

 ticed by the Indians long before the advent of European settlers. 

 The early settlers quickly took up the process and improved it. 

 Today more than 2 million gallons of syrup and upward of 5 

 million pounds of sugar are produced. The sugar maple grows 



