PRESENT FORESTS OF NORTH AMERICA 33 



Outliers of the deciduous forest occur on the Michigan peninsu- 

 las. The southern boundary extending from North Carolina to 

 Mississippi and reappearing west of the river of that name in 

 Arkansas, Louisiana and Texas, passes gradually into a transition 

 zone where there is a nearly equal commingling of the deciduous 

 and the evergreen species of the adjacent regions. Locally, as 

 determined by soil conditions, nearly pure stands of one of the 

 other will dominate. The commonest conifers in such situations 

 are the loblolly pine {Pinus taeda) or scrub pine {Pinus echinata) 

 while the most common deciduous species are the post oak {Quercus 

 minor), the Spanish oak {Quercus digitata) and the blue jack oak 

 {Quercus hrevifolia) . 



The southeastern Evergreen Coniferous forest extends from the 

 mouth of the Chesapeake Bay southward along the Coastal Plain 

 of the Atlantic and Gulf states in a belt from 100 to 200 miles in 

 width until it is interrupted by the bottom lands of the Mississippi 

 River, reappearing in Louisiana and southeastern Texas. Outside 

 the river bottoms with their variety of deciduous species this belt 

 is characterized by the extensive areas of nearly pure but open 

 stands of the long leaf pine {Pinus palustris) or the cuban pine 

 {Pinus carihaea). The coastal margin is characterized by the 

 live oak, the sand pine, the palmetto, etc., while the bottoms and 

 shallow ponds contain various gums, hickories, water oaks, ashes 

 and the sycamore and bald cypress — the latter and the long leaf 

 pine being undoubtedly the most valuable commercially. 



THE PACIFIC REGION 



The Pacific forest region may be considered as comprising all of 

 western North America between the Rocky Mountain front and 

 the Pacific coast. This is a vast area and one containing an un- 

 usual variety of topography, climate and soils. The major in- 

 fluence that has determined the presence or the absence and the 

 relative density of tree growth is the peculiar distribution of the 

 chmate as expressed more especially in the rainfall. The north- 

 west coast from northern California northward is a region of very 

 heavy rainfall and consequently it has a dense forest cover of large 



