Semi-natural and intensive silvicultural systems for the boreal mixedwood forest
Boreal mixedwood forests of aspen and white spruce are found on mesic sites in the western boreal forest. In the natural development of mixedwood stands, aspen is usually the first species to dominate the site. However, depending upon spruce seed sources and seedbeds, spruce can establish immediately after disturbance or in the next several decades. In most cases, spruce grow in the understory of deciduous species during its early development. If there are no spruce seed sources, aspen may be the sole tree species for a long period. Im most circumstances, however, the longer-lived and taller white spruce eventually becomes the dominant species. If stands remain undisturbed for long periods, they will likely become uneven-aged mixtures of spruce and balsam fir.
Lieffers, V.J.; Macmillan, R.B.; MacPherson, D.; Branter, K.; and Stewart, J.D., "Semi-natural and intensive silvicultural systems for the boreal mixedwood forest" (1996). Aspen Bibliography. Paper 1711.