2 BULLETIN 55, U. S. DEPAETMENT OF AGRICULTURE, 
white pine, is based partly on the actual inferiority of balsam fir to 
those species and partly to insufficient familiarity with the wood. 
To determine impartially the economic yalue of balsam fir, its dis- 
tribution, present stand and cut in the various States where it occurs, 
as well as its qualities and possibilities as a forest tree, was the purpose 
of two summers' study in the Adirondacks, in Maine, and throughout 
the whole of the tree's commercial range. It was believed that by 
pointing out the possibility of using balsam fir in places where 
originally only spruce had been used, and by learning its peculiarities 
as a forest tree, the heavy drain upon our waning supplies of spruce 
might be slightly decreased, and that suggestions for the proper 
management of our spruce forests, in which balsam fir holds an 
important place, could be formulated. 
DISTRIBUTION OF BALSAM FIR. 
Balsam fir (Abies balsamea Mill.) is a tree chiefly of the Northeast, 
although it occurs here and there in the mountain ridges of southern 
Virginia and extends westward in Canada as far as Mackenzie River. 
(See map, fig. 1.) 
Moisture and temperature are the two main factors influencing its 
distribution. It requires a cold climate and a constant supply of 
moisture at its roots. A mean annual temperature not exceeding 
40° F., with an average summer temperature of not more than 70° F., 
and a mean annual precipitation of not less than 25 inches evenly 
distributed throughout the year, are the necessary conditions for its 
growth. It extends farther north than red spruce, but is left slightly 
behind by black and white spruce, tamarack, aspen, and paper birch. 
Though in Canada balsam fir extends almost to the Rocky Moun- 
tains, in which it is doubtless supplanted by Alpine fir (Abies lasio- 
carpa), 1 it does not occur in continuous large forests west of the 
one hundredth meridian, and in the United States its western limit is 
found in Minnesota. One of the principal reasons for this is the 
increasing dryness of the air which the tree encounters in its westerly 
distribution. The mean annual rainfall gradually decreases from 
the east toward the west. In Maine, where balsam fir reaches its best 
development, the rainfall amounts to 43 inches; in Minnesota, where 
balsam is of poor development, it is less than 26 inches. Farther west, 
in North Dakota, the annual rainfall drops to about 18 inches, and no 
balsam fir is found. While the increasing dryness of the air influences 
the western distribution of balsam fir, the increasing temperature con- 
trols its southern distribution, limiting it to higher and higher eleva- 
tions the farther south it extends, until it gives way to Frazer fir 
(Abies frazeri (Pursh.) Lindl.) on the highest mountains of West Vir- 
ginia, North Carolina, and Tennessee. 
i John Macoun. Geological and Natural History Survey of Canada: Catalogue of Canadian Plants. 
Part III— Apetalse, p. 473. 
