Dynamics and structure of mountain autochthonous spruce-beech forests: impact of hilltop phenomenon, air pollutants and climate

Abstract

Mountain forests are strongly influenced by the extreme climate, short growing season and stress from environmental pollution and lower fertility of soils. The paper analyses the effect of the environment (climate and air pollutants) on the structure, production and dynamics of autochthonous spruce-beech forest stands in protected areas in the summit parts of the Orlické hory Mts., Czech Republic. The spatial pattern of tree layer was random in lower parts below the summit and aggregated under the hilltop phenomenon on an extreme edaphic site, such as aggregated horizontal structure of natural regeneration. In most cases, the relationship between the spatial pattern of tree layer and natural regeneration was significantly negative (α = 0.05) at a smaller distance (from stem to 0.6-6.1 m) except stands under the strong hilltop phenomenon (positive effect to 2.1 m). The stand density ranged from 440 to 760 trees ha -1 and the number of natural regeneration was 4 584-6 360 recruits ha -1. Dominant height decreased with increasing influence of hilltop phenomenon (P < 0.001). The volume of live trees was 239-536 m 3 ha -1. The radial growth of dominant European beech (Fagus sylvatica L.) indicated a relatively balanced long-term trend of tree-ring width in 1900-2014, but diameter increment of admixed Norway spruce (Picea abies /L./ Karst.) after 1978 significantly decreased (P < 0.001) and since 1998 radial increment in spruce distinctly increased. Radial growth of spruce was significantly negatively correlated with mean SO 2 and NO X concentrations, especially in April (P < 0.001), but there was no effect on radial growth of beech. Air pollution had a significantly higher negative effect on radial growth of spruce on the hilltop compared to the lower part of the hill. The correlation between radial increment and temperature was stronger than in precipitation for both species in mountain areas compared to lowlands. The hilltop phenomenon significantly influenced the structure of spruce-beech mountain forests. The lowest dynamics was observed in stands in middle slope parts compared to summit parts of the hill.

Joining of the historical research and future prediction as a support tool for the assessment of management strategy for European beech-dominated forests in protected areas

“…(3) Increasing CO 2 content can increase the biomass (and wood production) of beech stands in newly occupied areas at higher altitudes (Machar et al 2017b). Králíček et al (2017) confirmed these results by founding of strong correlation between the radial increment of European beech and the temperature in mountain areas. Long-term simulations of climate change's impact on forest dynamics in Silver fir-European beech stands in Dinaric Mountains in Slovenia (Mina et al 2017) revealed that European beech will be favoured by higher temperatures in contrast to drought-induced growth reduction in Silver fir.…”

Long-term transformation of submontane spruce-beech forests in the Jizerské hory Mts.: dynamics of natural regeneration

“…(Bulušek et al 2016;Králíček et al 2017). On the other hand, in those studies a positive relationship of recruits and tree layer in beech was confirmed on plots with extreme site conditions due to natural layering.…”

“…Similar numbers like those were reported by others researches in the Czech Republic from spruce-beech near-natural forest in the Orlické hory Mts. -37,230 recruits ha -1 Králíček et al 2017), while higher regeneration density were observed in the Voděrady Beechwoods -60,859 recruits ha -1 , in Krkonoše Mts. -75,395 recruits ha -1 (Vacek et al 2015a) or in old-growth forest in Slovenia -62,000 recruits ha -1 (Dusan et al 2007).…”

Structure and dynamics of spruce-beech-fir forests in Nature Reserves of the Orlické hory Mts. in relation to ungulate game

“…Natural and semi-natural mixed forests are currently very intensively studied subject (Paluch 2007;Kucbel 2010;Liira et al 2011;Králíček et al 2017;Meier et al 2017). In comparison with managed stands, these forests have many-times higher species diversity (Lindenmayer & Franklin 2002;Bauhus et al 2009), self-regulatory ability (Korpeľ 1995) and stability against external influences (Knoke et al 2008;Liira et al 2011).…”

“…Very diverse structure of fenced forest stand was also observed from other research in the Trčkov NNR (B; index 8.61) compared to lower complex diversity in unfenced stand (B;7.66;Vacek et al 2013), such as in other mixed not fenced spruce-beech forest in Orlické hory Mts. (B 6.57 -8.05;Králíček et al 2017). Study forest stands with pronounced age, spatial and species differentiation are generally considered as ecologically stable (Klopcic & Boncina 2011).…”