Evaluating similarity of radial increments around tree stem circumference of European beech and Norway spruce from Central Europe

Abstract

Extracting cores from a tree using an increment borer has been standard practice in dendrochronological studies for a long time. Although empirical rules exist regarding how many samples to take and which methodology to apply, comparatively few studies provide quantification of the similarity of relative tree-ring-widths (TRW) around the stem circumference. The aim of this study was therefore to precisely measure the similarity of standardised TRWs around the stem circumference and to provide objective suggestions for optimal core sampling of Norway spruce (Picea abies Karst. [L.]) and European beech (Fagus sylvatica L.) growing in Central European temperate forests. A large sample of cross-sectional discs was used from Norway spruce and European beech trees growing on various slopes, at different altitudes and biogeographic regions across the Czech Republic and Slovakia. The similarity of TRWs measured in different coring directions was analysed by testing the relativized TRW around the trunk (rTRW). Comparison of rTRWs revealed no significant differences between coring directions, indicating that the relative increment was the same around the radius. The results also showed the high similarity between the rTRWs to be independent of both slope inclination and altitude. Moreover, the reconstruction of proportional tree diameters and basal areas backward in time from one core sample and one measurement of tree diameter (basal area) at the time of sample extraction is possible with reasonable precision.

Genomic basis for drought resistance in European beech forests threatened by climate change

“…Weather data from our study area from 1950 onwards suggested that the climatic conditions for beech trees in the area investigated changed dramatically during this period. Roughly estimating the tree age from their trunk circumference ( Bošeľa et al, 2014 ), more than a third of the trees were already in place at the beginning of this period. About 60% were recruited prior to the acceleration of temperature change from the 1980s onwards.…”

Oak (Quercus spp.) response to climate differs more among sites than among species in central Czech Republic

“…All samples were extracted using a Pressler borer at breast height. Because the between-tree variability within a site is much higher than the within-tree variability around the stem (Bošeľa et al, 2014), one core per tree was extracted. Likewise Fritts (1976) suggested that for climate studies, one core per tree is sufficient if more than 14 trees are sampled.…”

Thinning decreases above-ground biomass increment in central European beech forests but does not change individual tree resistance to climate events

“…In 2018, fifteen to forty-two dominant, co-dominant and sub-dominant trees were selected in the C and T plots at each of the four sites selected for this research (Table 1). One core was taken from each selected tree using Pressler increment borer (Bosela et al, 2014), perpendicular to the slope of the site, generating a total of 179 tree-ring-width (TRW) series. Core samples were air-dried and sanded to increase the visibility of annual tree rings; their widths were established at 0.001 mm resolution using the LINTAB (RINNTECH.…”