Remise en production des bétulaies jaunes résineuses dégradées : étude du succès d'installation de la régénération | Restoration of degraded yellow birch production: study of successful regeneration installation
2007
Gastaldello, P. | Ruel, J.C. | Lussier, J.M.
The abundance of poor quality stands in the North American hardwood and mixedwood forests poses important regeneration challenges. These stands have an open canopy with a well-developed shrub layer dominated by noncommercial species. The present study aims at testing the efficiency of a natural regeneration approach using a combination of brushing and spot scarification in the cleared strips. Four high-graded stands from the mixedwood zone in Quebec were selected and strips were cleared with a brush saw. Four microsite types created by the scarification were studied: 1-m and 2-m wide pockets, mounds and undisturbed forest floor. The amount of dispersed yellow birch seeds was adequate for two out of the three years of the study. Yellow birch establishment was in phase with seed years and was better on disturbed microsites. Best establishment was observed in seed spots and light conditions in these microsites after three years were better than on mounds or undisturbed ground. On the latter two, survival will likely be impaired by the poor light conditions. Seed spots remain receptive three years after scarification. Softwood regeneration was poor due to a lack of seed trees. The study has shown that seed tree abundance remains sufficient for natural regeneration even in these open stands. It also showed a very rapid regrowth of competing vegetation when root systems and seed banks were not removed by site preparation.
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