Suitable conditions for natural regeneration in variable retention harvesting of southern Patagonian Nothofagus pumilio forests

TORO MANRÍQUEZ, MÓNICA D.R.; CELLINI, JUAN M.; LENCINAS, MARÍA V.; PERI, PABLO L.; PEÑA ROJAS, KAREN A.; MARTÍNEZ PASTUR, GUILLERMO J.

Ecological Processes

Springer

Lugar: Amsterdam; Año: 2019 vol. 8 p. 18 - 18

Background: Variable retention (aggregated and dispersed retention) prescription for Nothofagus pumilio was proposed for timber purposes and biodiversity conservation, facilitating the natural regeneration by opening the canopy. Harvesting generates different microenvironments and presents dissimilar conditions for seedling establishment and growth due to synergies (positive or negative) with biotic and abiotic factors. The aim of this study was to evaluate regeneration in different microenvironment conditions within the managed stands five years after harvesting.Methods: Remnant forest structure after harvesting, environmental data (light and moisture) and microenvironments were characterized in managed stands, and 105 regeneration plots were measured (3 stands × 7 microenvironments × 5 replicas), characterizing the seedling bank structure, growth and eco-physiology. Univariate and multivariate analyses were conducted for comparisons.Results: Microenvironments offered different environmental conditions (soil moisture and light) for regeneration. Plants under debris and dicot plants showed better eco-physiological performance, favouring seedling establishment and growth. This performance was followed by plants growing under monocots or located in the dispersed retention without protection of other plants. The most unfavourable microenvironments were related to the closeness to the remnant trees (inside the aggregates or close to the trees in the dispersed retention) or in heavily impacted areas (skidder extraction roads).Conclusions: Increasing the ratio of favourable microenvironments in the harvested areas will improve the natural recruitment and growth of the natural regeneration after harvesting. It is necessary to develop new harvesting methods that decrease the unfavourable microenvironments (e.g. road density or excessive woody accumulation), allowing to assure the success of the proposed silvicultural method.