BALSAM FIB. 29 



where balsam fir occurs scatteringly, the number of seedUngs per 

 acre is small, often only 700 to 1,000, though occasionally, if there 

 are a number of large balsams, the number may reach 50,000. The 

 number of seedlings is, of course, lai^est in pure stands of balsam, 

 where they may be 300,000 and more to the acre. In mixture with 

 spruce in the swamps and flats the number of balsam seedhngs will 

 vary from several thousand to 200,000 and more, according to the 

 number of large seed-bearing balsams in the stand. 



TOLERANCE. 



Balsam fir requires less light than tama,rack, white pine, and white 

 cedar, but more hght than either red spruce or hemlock. It will, 

 however, endure more shade on deep, moist soils than on poor, shallow 

 ones. In mixture with spruce, mature healthy balsam invariably 

 towers above the former. Similarly, in a mixed hardwood forest, 

 balsam fir, when fully developed, is the dominant tree. For the 

 first five or six years of its Hfe, balsam will grow in dense shade, but 

 as it develops it demands more and more hght. On moist soils, how- 

 ever, it may thrive without being in the top story of the forest, and 

 beneath white birch and poplar, also, it often remains apparently 

 healthy and vigorous. But where it comes in under a hardwood 

 forest already established, its leader is usually stunted or killed 

 when it enters the hardwood foliage. A broken hmb or leader often 

 affords the means of entrance for rot, and though balsam, especially 

 on deep, moist soil, is capable of recovery after a long period of 

 suppression, it is apt in such cases to be unsound. Many trees 

 were found to be rotten in the middle at the point of suppression, 

 with no visible point of entrance for the rot. Others were found 

 100 years old, with a height of 18 feet and a diameter of 3 inches, 

 which, after 66 years of suppression, retained sufficient vitahty to 

 grow rapidly after again receiving the light. 



SOIL AND MOISTURE REQUIREMENTS. 



Though their demands upon soil are very similar, balsam fir 

 requires for its best development a richer and moister soil than 

 does spruce. With its more northern distribution it seeks the cool 

 and moist north and east slopes in preference to other exposures. 

 In the Adirondacks it is hardly ever found on the abrupt, rocky, 

 southwest slopes, with thin soil, on which spruce often forms a pure 

 stand and reaches a good development. Balsam fir attains its 

 best growth and largest sizes on the flats, the soil of which is usually 

 a moderately moist, deep, sand loam. In the wet swamps with 

 acid soils, as well as on pure sand, it thrives but poorly. 



