Tree Species

- Aspen


- Balsam Fir

Balsam Fir

Site Conditions

Range of balsam firBalsam fir grows on a wide range of inorganic and organic soils and on wet to dry sites. It is most common on wet to moist sites, where soil mois- ture is adequate throughout the growing season and standing water may be present during part of the season. On moist sites balsam fir is gradually replaced by northern hardwoods such as sugar maple. On wet sites it usually is dominated by black spruce and tamarack. Good sites are found on well-drained loams and moderately well- drained silt loams, clay loams, and clays. It grows where pH is 5.1 to 6.0, but does best with pH 6.5 to 7.0 in the upper organic layers. A site index (Table 6-1) is most reliable when measuring dominant balsam firs that have not been previously sup- pressed in even-aged stands or by assessing the site index of associated species (Appendix B-2: Site index curves for balsam fir in the Lake States). The balsam fir site index is unreliable in uneven-aged stands.

Table 6-1. Comparative site index for balsamfir and common associates.
Balsam fir
Quaking aspen
Paper birch
Black spruce
Northern white-cedar
60
70
70
60
40
50
60
55
50
35
40
50
40
40
30
30
35
25
30
25
Source: Johnston, W. F. 1986. Manager’s handbook for balsam fir in the north central states. General Technical Report NC-111. USDA Forest Service, North Central Forest Experiment Station. P. 5.