4 BULLETIN 55, U. S. DEPARTMENT OF AGKICULTUEE. 



Southward balsam & is found almost all over Canada, particularly 

 ill its maritime provinces — Quebec and Ontario — in northern New 

 England, and in the northern parts of New York, Michigan, Wisconsin, 

 Minnesota, and northeastern Iowa. Along the Appalachian Moun- 

 tains it extends through western Massachusetts, over the Catskills of 

 New York, and tlii'ough westei'n Pennsylvania to the mountains of 

 southwestern Virginia. 



The heaviest commercial stands of balsam fir are found in Canada, 

 in Quebec and Ontario. On the Cape Breton Islands, according to 

 Dr. Fernow,^ balsam fir forms a solid forest, with not over 15 per cent 

 of spruce and a small admixture of paper bhch, covering a plateau of 

 1,000 square miles. It is estimated to compose more than 50 per cent 

 of the forest, 150,000 square miles in extent, on the southern slope of 

 the Laurentian shield, south of the height of land. In the United 

 States balsam fir is found in commercial quantities in most of Maine, 

 the northern parts of New Hampshire, Vermont, New York, and to 

 some extent also in the swamps of northern Wisconsin, northern 

 Michigan, and Minnesota, or, in all, over an area of approximately 

 35,000 square miles. 



FOREST TYPES. 



The same factors that control the geographical distribution of 

 balsam fir influence to a great extent also its local occurrence. ]\Iaine, 

 with an average summer temperature of only 62.5° F., an average 

 winter temperature of 20° F.^ and a mean annual rakifall of 43 inches, 

 presents most favorable conditions for the tree's growth, and, indeed, 

 here balsam fir is in general more thrifty than in any other State in 

 which it occurs. This is shown in every way — in the greater height, 

 larger diameter, greater clear length, more cylindrical shape of the 

 trunk, and the smoother appearance of the bark, indicating a more 

 rapid growth. 



The forest types in which balsam fir occurs in Maine, as well as 

 throughout northern New York, New Hampshire, and Vermont, 

 may be classified as swamp, flat, hardwood slope, and mountam top. 



SWAMP. 



The swamp type occupies low, poorly drained, swampy land which 

 never becomes entii'ely dry, and on which sphagnum and other 

 mosses form the predominating ground cover. In such swamps 

 balsam fir grows in dense stands and remains exceedingly slender, but is 

 remarkably free from injury by fungus, especially from ground rot and 

 from wind and frost cracks. It often grows nearly pure, though com- 

 monly it is mixed with black and red spruce, white cedar, and tamarack. 



On account of its small size and slow growth, the balsam fir of the 

 swamps is of little commercial value. This slow growth may be attrib- 



1 Forest Problems and Forest Resources of Canada, by Dr. B. E. Fernow, University of Toronto. 

 Proceedings of the Society of American Foresters, Vol. VH, No. 2, 1912. 



