Gap regeneration in near-natural European beech forest stands in Central Bohemia – the role of heterogeneity and micro-habitat factors

Abstract

Gap regeneration in a European beech (Fagus sylvatica L.) forest reserve was analyzed in relation to within-gap resource heterogeneity and ground vegetation competition. The study was carried out in two one-hectare permanent research plots (PRP) which included five smaller research plots (RP) encompassing two large gaps (500-700 m 2 ), two small gaps (300-400 m 2 ), and location under canopy. The coverage of woody regeneration, ground vegetation, dead wood, seedling density in eight height classes, characteristics of dominant trees of the beech regeneration, and the total thickness of holorganic horizons were measured. Soil moisture and light conditions were also assessed in selected sample plots. The relative direct and diffuse light was estimated by hemispherical photography. Small gaps showed both the highest cover of tree regeneration and the highest density of individuals per hectare. Slightly less regeneration was recorded in large gaps, while under closed canopy, regeneration densities were 5-10 times lower than in small gaps. Beech regeneration cover and the size (diameter and height) of dominant beech seedlings were positively related to relative diffuse light and negatively related to ground vegetation cover. The latter was positively related to diffuse light and soil moisture content. A pronounced statistically significant contrast in the cover and size of beech regeneration in relation to micro-site conditions (diffuse light, cover of graminoids) was only confirmed between sample plots located below canopy cover and those within gaps. Graminoids, in particular Calamagrostis epigejos L., occurred mainly in the large gap centre and along the southernmost edge of the large gap, increasing competition for resources here. The cumulative cover of ground vegetation and regeneration was relatively low (9-56%) compared with more mesic natural beech forests. The indicated negative influence of direct light at the northern gap edge suggests that extension of gaps on comparable sites in managed forest should not proceed in this direction.

Capturing ecological processes in dynamic forest models: why there is no silver bullet to cope with complexity

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Spatial pattern of relict beech (Fagus sylvatica L.) forests in the Sudetes of the Czech Republic and Poland

“…The amount of natural regeneration is differentiated according to the herb layer cover (Bílek et al 2014) and topography (Vacek et al 2015c).…”

Climate influence on radial growth of Fagus sylvatica growing near the edge of its distribution in Bükk Mts., Hungary

“…Probably due to the more xeric conditions, a significant increase in climate impact on growth has been detected as also described by several other studies (Csóka et al 2009;Jump et al 2010;Mátyás et al 2010). The projected enhancement in aridity will surely be a major challenge also to the natural regeneration of beech forests (Bílek et al 2014).…”