Influencia del micrositio y la exposición en la regeneración de bosques de Nothofagus pumilio afectados por Castor canadensis en Tierra del Fuego: un análisis exploratorio

Abstract

Influencia del micrositio y la exposición en la regeneración de bosques de Nothofagus pumilio afectados por Castor canadensis en Tierra del Fuego: un análisis exploratorio Influence of microsites and exposure in tree regeneration of Nothofagus pumilio forests affected by Castor canadensis in Tierra del Fuego: An exploratory analysis

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

“…In other silvicultural treatments, such as shelterwood cuts, create less microenvironments due to the harvesting homogenizes the managed stand (Martínez Pastur et al 2000). Besides this, many microenvironments in primary forests allowed to maintain a seedling bank that survives for long periods of time (Martínez Pastur et al 2012;Toro Manríquez et al 2018). Soil moisture and light availability mainly conditioned the survival of the seedling, and plants quickly reacted after canopy opening.…”

“…Canopy opening, both in natural conditions or under human-induced disturbances, changes the availability of indispensable resources and/or create new microsites that allowed the establishment and growth of seedlings (Christie and Armesto 2003;Bailey et al 2012;Valenzuela et al 2016;Toro Manríquez et al 2018). Harvesting creates new microenvironments by generating large amounts of woody debris, which can potentially improve the eco-physiological response and the growth of seedlings compared with less shelter conditions (Martínez Pastur et al 2012.…”

“…Both factors (moisture and light availability) can explain most of the establishment, growth, and eco-physiological performance of the seedlings (Rey et al 2004;Lencinas et al 2007;Martínez Pastur et al 2007aPeri et al 2009;Soler et al 2011;Henn et al 2014). However, negative synergies have been observed in some microenvironments, where large canopy openings can produce drying effects, acting as a limiting factor for regeneration (McIntire et al 2016;Toro Manríquez et al 2018), as well as higher radiation levels that can increase the evaporation rates (Martínez Pastur et al 2011a, 2011b.…”

“…Dispersed retention between aggregates offered shelter or generate competition with seedlings for soil water and light availability (Martínez Pastur et al 2011b). These synergies (positive or negatives) depend on debris amount and impacts on over forest soil (Heithecker and Halpern 2007;Bailey et al 2012;Martínez Pastur et al 2011b, the remnant canopy cover (Torres et al 2015), and the changes produced over understory plants, such as monocots or dicots that can favor or limit the seedling performance (Hörnberg et al 1997;Kupferschmid and Bugmann 2005;Blood and Titus 2010;Vodde et al 2010;Martínez Pastur et al 2012;Toro Manríquez et al 2018).…”

“…Nothofagus pumilio can quickly adjust to the potential changes in the environment (e.g., exposure to high light levels) (Martínez Pastur et al 2011c). However, mortality after harvesting usually occurred (Martínez Pastur et al 2013), e.g., recruitment is higher, and mortality is less in shaded areas close to forest edges (Heinemann et al 2000;Heinemann and Kitzberger 2006;Toro Manríquez et al 2018). Besides this, other effects that could be modified in these microenvironments are related to the dynamics of the seedling bank, forest biometric variables, allocation of the biomass, and eco-physiological performance (e.g., stomatal conductance was higher in seedlings associated with plants or nurseries than other environments with similar moisture conditions) (Valenzuela et al 2016).…”