Landscape and microenvironmental conditions influence over regeneration dynamics in old-growthNothofagus betuloidesSouthern Patagonian forests

Abstract

Old-growth forests present a mosaic of different conditions resulting from the natural forest structure of the stands. Nothofagus betuloides forests have high spatial variability in regeneration without a clear correlation with overstory, and could be related to location of the stands in the landscape. The objective was to evaluate the influence of macro-and microvariables over regeneration dynamics in old-growth N. betuloides forests, considering the effect of landscape (altitude and influence of the sea) and microenvironment conditions in the forest floor (closeness to trees, pits, understory cover type and bare soil). A total of four sites and 24 stands were sampled including forest structure, regeneration, understory cover and microclimate variables. Macro-(landscape) and micro-(microenvironment conditions in the forest floor) variables influenced over regeneration dynamics. Natural regeneration values (0.17 million ha 71 in the drier site vs. 44.52 million ha 71 in the other sites) not greatly depended on forest structure variables, but they were related to soil moisture (14% vs. 29-36% volumetric soil water content). Microenvironment conditions in the forest floor determined the recruitment as well as regeneration density, age and distribution of seedlings, whereas different soil moisture were related to each microenvironment type, generating positive (bare soil, ferns and mosses growing in turfs) or negative (mosses growing in mats, pits and proximity of the overstory trees) effects over regeneration, according to the soil moisture levels. These findings can be used to understand the functional integrity of the old-growth forest ecosystems and to propose silvicultural prescriptions to ensure regeneration recruitment and maximize growth potential in N. betuloides forests.

The influence of canopy-layer composition on understory plant diversity in southern temperate forests

“…Regarding solar radiation variables, it is known that beech crowns transmit only a small proportion of daylight to the forest floor (Ellenberg 1996;Barbier et al 2008) and that the effective amount of radiation reaching the forest floor is determined by forest structural characteristics and tree species (van Oijen et al 2005;Barbier et al 2008;Promis et al 2008;Martínez Pastur et al 2012;Kuninaga et al 2015). According with this, we expected the highest level of solar radiation in deciduous forest, because the canopy of N. pumilio is quite sparse and their leaves are substantially thinner than N. betuloides.…”

Site quality influence over understory plant diversity in old-growth and harvested Nothofagus pumilio forests

“…Specific micro-environmental conditions under closed canopies are usually found in Nothofagus forests, e.g. pits, mounds, protected areas under large debris, close or far to big trees, rotten wood of dead trees, small gaps (Lencinas et al, 2008b;Martínez Pastur et al, 2012). At a greater scale, continuous presence of sensitive species on the landscape are usually related to variations in old-growth qualities of forests (Ohlson et al, 1997), as gap presence and tree-layer structure, availability of snags and dead wood of various sizes and decay stages.…”

The southernmost beech (Fagus sylvatica) forests of Europe (Mount Etna, Italy): ecology, structural stand-type diversity and management implications

“…Williams-Linera et al 2000;Gea-Izquierdo et al 2004;Shimano 2006;Guo & Werger 2010;Martínez-Pastur et al 2012). Similarly different studies have been conducted on European beech stands, especially at their southern mountain-Mediterranean edge (Poli & Puzzolo 1999;Christensen et al 2005;Peñ uelas et al 2007;Tsiripidis et al 2007;Mercurio & Spampinato 2008;Manes et al 2010;Papalexandris & Milios 2010).…”