400 The New York State College of Forestry 



Frostless period in general 130 to 150 days. 



More or less arbitrarily distinguished from the maple, beech, 

 birch, hemlock-containing (and often dominated) Adirondacks 

 and Catskills by absence (generally) of red spruce, balsam, white 

 birch, etc., on the one hand and presence of certain species of 

 Zone B which are lacking in the Adirondacks. 



Similar extensions in mountains of New England, the Maritime 

 Provinces and especially the St, Lawrence region of Quebec and 

 Ontario (but penin.sular Ontario is strongly like Zone B) and 

 Michigan and Wisconsin. 



D. Canadian-Transition Zone: 



Dominance of maple, beech, yellow birch, hemlock, white pine 

 as in Zone C, but addition and tendency to dominance in special 

 situations and, especially at greater elevations, of red spruce, 

 balsam, paper birch, mountain ash, etc. Further characterized 

 by absence of oaks (few exceptions), hickories, elms, and, 

 naturally, of tulip-poplar, chestnut, etc. (i. e., dominant species of 

 Zone B). Further, by the decreasing prominence of forest floor 

 herbaceous growth-forms of the Appalachian region generally, 

 and substitution of more northerly ranging species (see below). 



Dominant tree species: 



Red Spruce Picea rubra (DuRoi) Dietr. 



Black Spruce Picea mariana (Mill.) B. S. P. 



Balsam Fir Abies balsamea (L.) Mill. 



Pussy Willow, Glaucous Wil- 

 low Salix discolor Mulil. 



Bebb 's Willow Salix rostrata Richards. 



Mountain Ash Pyrus americana (Marsh.) DC. 



Distribution of D in New York 

 In the Catskills from about 2,000 feet to 3,700 feet (above which 

 Canadian Zone forest is indicated by dropping out of maples, 

 beech, hemlock and pine) and in the Adirondacks generally as 

 climax forest up to 3,500 feet more or less. 

 Growing season 100 to 130 days, more or less. 



