The effects of harvest intensity and seedbed type on germination and early survival of balsam fir and white spruce in the southern boreal forest

The effects of harvest intensities and seedbed type on germination success and early (first summer) survival for balsam fir ( Abies balsamea (L.) Mill) and white spruce ( Picea glauca (Moench) Voss) were examined. The harvest intensities canopies included a 1/3 rd and 2/3 rd partial cut, a clearcut and a control (full canopy). The seedbeds were mineral, humus (O h ) and organic (O f ). In clearcuts, seedbeds included both slash and non-slash treatments. Germination of both species was negatively affected by an increase in harvest intensity. The reverse effects of harvesting intensity were observed during subsequent survival, where spruce was much more affected than fir by a reduction in canopy cover. Cumulative survivorship analyses showed that clearcuts without slash were the worst areas for early plant establishment. Mineral seedbeds allowed the highest rates of seedling establishment for both species, although survival of fir was highest on O f seedbeds. Cumulative survivorship showed that mineral soil is the most suitable substrate for establishment. This finding however, was not strong for spruce, suggesting adverse effects of mineral soils with a high clay content. The slash treatment benefited the establishment of fir, but not for spruce. This study showed the strong initial influence of harvesting intensity and seedbed type. The effects of light however, quickly become muted when cumulative survivorship is considered. Conversely, seedbeds have persistent effects on early establishment.