Canadian Forest Service Publications
Forest regeneration in gaps seven years after partial harvesting in riparian buffers of boreal mixedwood streams. 2014. Mallik, A.U.; Kreutzweiser, D.P.; Spalvieri, C.M. 2014. Forest Ecology and Management 312:117-128.
Issued by: Great Lakes Forestry Centre
Catalog ID: 35236
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Partial harvesting in boreal forest riparian buffers has been proposed as a management tool to emulate natural disturbance (END) along streams and lakes to increase shoreline habitat complexity through ensuing forest regeneration. We investigated the effect of partial harvesting in stream-side riparian buffers on regeneration of canopy species (Abies balsamea, Betula papyrifera, Picea glauca, Picea mariana and Populus tremuloides) by testing the hypothesis that juvenile trees would be more abundant, species-rich, and larger in gaps than in non-harvested buffers, and that those differences would be proportional to gap size. Our main objective was to determine what gaps sizes are conducive to promote tree and woody shrub regeneration in stream-side riparian areas of boreal mixedwood forests. We compared woody plant regeneration among harvest gaps varying in size (small, 10–20 m2; medium, 21–100 m2; and large, >100 m2), and contrasted with regeneration under closed canopy in unharvested buffers and undisturbed reference forests. We found that woody plant communities in partial harvesting gaps were denser and more diverse than unharvested buffers. They were more so in medium to large gaps and consisted of shade-intolerant and early successional species. Favorable light and soil temperature in the large gaps appear to be responsible for this. We concluded that intentional shoreline disturbance aiming to achieve increased riparian habitat complexity and early successional forest community is possible by partial harvesting at up to 50% basal area removal. However, as END principles are increasingly applied to riparian forest management, it will be necessary to test and monitor the effectiveness and longer-term ecological responses of riparian communities to such management at catchment and landscape levels.
Plain Language Summary
We examined the effects of partial harvesting in mixedwood forests along streams on regeneration success. The harvesting of gaps of various sizes in these areas is a technique used to create more natural shorelines than unharvested buffers and follows a new forest management direction of emulating natural disturbances. The goal was to increase habitat complexity by creating disturbances of sufficient size to promote early-successional regeneration and support biodiversity. We wanted to determine what gap size was most conducive to promoting this type of regeneration. We found that seven years after harvesting, woody plant communities in partially harvested gaps were denser and more diverse than in unharvested buffers, especially in medium and larger size gaps (greater than 20 m2). We concluded that the results were best achieved by partial harvesting of up to 50% basal area removal in these areas.