Producción diferencial de biomasa en plántulas de Nothofagus pumilio bajo gradientes de luz y humedad del suelo

Abstract

Producción diferencial de biomasa en plántulas de Nothofagus pumilio bajo gradientes de luz y humedad del suelo Differential biomass productivity of Nothofagus pumilio seedlings under light and soil moisture gradients

Canopy structure analysis for estimating forest regeneration dynamics and growth in Nothofagus pumilio forests

“…Harvesting, by opening the canopy, increased radiation at ground level, e. g. it was 2.4-2.9× greater with 50% original basal area (Caldentey et al 2009). Natural regeneration dynamics and subsequent growth determined by biomass compartmentalization (Lencinas et al 2007) and photosynthetic efficiency depend on the interaction between radiation levels and soil moisture. There is a negative interaction that can influence the fine root dynamics thus affecting nutrient and water uptake (Martínez Pastur et al 2007a), as was cited for N. solandri and N. menziesii (Sun et al 1995).…”

“…However, while greater canopy opening reduces the effective sheltering function of the remnant overstory (Howard 1973;Nuñez and Bowman 1986), soil moisture and radiation at ground level increase, which have positive or negative influence effects over regeneration. Both factors affect the regeneration growth rate by changing their ecophysiological performance (Lencinas et al 2007;Martínez Pastur et al 2007a;Peri et al 2009). Therefore, in this study, the objectives are: (1) to evaluate the regeneration dynamics of N. pumilio along different forest canopy structures and solar radiation transmissions and (2) based on these results discuss the current silvicultural practices.…”

“…The most commonly applied methods over the last decade were shelterwood and variable retention cuts . The silvicultural prescriptions applied under these systems are based on canopy opening to stimulate natural regeneration by modifying soil moisture and light availability at ground level (Heinemann et al 2000;Lencinas et al 2007;Martínez Pastur et al 2007a). To improve these silvicultural practices, it is necessary to understand the basis of inter-specific differences in seedling and sapling growth (Messier et al 1999), as well as the impact over flowering and seeding processes .…”

Environmental variables influencing regeneration of Nothofagus pumilio in a system with combined aggregated and dispersed retention

“…The magnitude of this change depends on the distance from the aggregates, the understory cover type, harvesting debris and the proximity of retained trees (Chen et al, 1993(Chen et al, , 1995Heithecker and Halpern, 2007). These microenvironments present differing conditions for regeneration, where light and soil moisture availability are the most important factors determining establishment, growth and eco-physiological performance (Heinemann et al, 2000;Heinemann and Kitzberger, 2006;Lencinas et al, 2007;Martínez Pastur et al, 2007;. Light availability is mainly modified by canopy opening and remnant overstorey spatial distribution (Caldentey et al, 2009;Promis et al, 2010).…”

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

“…The canopy opening determines a significant increase of the effective rainfall that reaches to the soil, increasing the moisture levels that can limit the seedling performance (Promis et al 2010;Martínez Pastur et al 2011b;Dreiss and Volin 2013). 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.…”