Pavel Šamonil

Trends and cyclical changes in natural fir-beech Forests at the north-western edge of the Carpathians

The vegetation of natural fir-beech forests on the western edge of the Carpathians was repeatedly surveyed in 1972(4) and 1994(5) on 34 plots in the Razula and Salajka reserves. Concurrently repeated whole-area dendrometric measurements of all live and dead trees were made together with maps of forest development stages. The maps were used to compare vegetation changes. The objective was to assess the tree layer dynamics, to discern vegetation development trends from cyclical changes, and to assess the changes of site conditions through phytoindication.The fir (Abies alba) population showed disrupted continuity of development associated with its pronounced withdrawal and replacement by beech (Fagus sylvatica). Rather than a cyclical change, the phenomenon is a trend that can be expected to become more dominant in the future. The reason for the interchange of the two species is seen in a fading response to the medieval colonization of Carpathian ridges connected with the exploitation of local forests for grazing and intensive litter raking.The herb layer was significantly modelled by changes occurring over time and by the dynamics of forest development stages. Species diversity in Razula was observed to increase. Salajka exhibited an invasion of acidophilous taxa (Luzula luzuloides, Vaccinium myrtillus) and decreased frequency of demanding taxa (Galeobdolon montanum, Dentaria enneaphyllos, Galium odoratum).Changes in the coverage ofDryopteris filixmas, Rubus idaeus andSenecio ovatus were interpreted as cyclical changes. No significant shifts were found in the species diversity between the stages. The herb layer at a disintegration stage was homogenized and exhibited the lowest tendency to gain relative control of the undergrowth; the tendency was highest at the optimum stage.The stages of forest development exhibited changes in soil nitrogen and soil reaction.

Contrasting local and regional Holocene histories of Abies alba in the Czech Republic in relation to human impact: Evidence from forestry, pollen and anthracological data

After the last glaciation, around 4000 BC, silver fir (Abies alba Mill.) spread to the area that is now the Czech Republic. This spread was not restricted to high mountains, but also took place across both highland and lowland landscapes. Historical forestry records from around AD 1500 mention a massive expansion of Abies alba, favoured by forest pasturing, litter raking and selective tree cutting. According to the current interpretation of these historical records, this expansion in Czech forests was extensive and lasted until AD 1800. On the other hand, pollen data coming mostly from the Alps consider silver fir as a species that is extremely sensitive to human impact. In this paper, we compare historical forestry reports with pollen and charcoal data from the Czech Republic. Both pollen and charcoal records show that Abies alba reached its maximum during the Bronze (2200—800/750 BC) and Iron Ages (800/750 BC—AD 0). While charcoal records indicate that silver fir wood was important also during the High Medieval, pollen data show that the High Medieval and Modern times were periods of a general decline in Abies. Our data suggest that the expansion of silver fir documented by historical records was not general but rather fragmented, probably according to actual form and the intensity of human impact, as well as environmental conditions. These historical records have contributed much evidence regarding the wider ecological tolerance of Abies.

The historical disturbance regime of mountain Norway spruce forests in the Western Carpathians and its influence on current forest structure and composition

In order to gauge ongoing and future changes to disturbance regimes, it is necessary to establish a solid baseline of historic disturbance patterns against which to evaluate these changes. Further, understanding how forest structure and composition respond to variation in past disturbances may provide insight into future resilience to climate-driven alterations of disturbance regimes. We established 184 plots (mostly 1000 m2) in 14 primary mountain Norway spruce forests in the Western Carpathians. On each plot we surveyed live and dead trees and regeneration, and cored around 25 canopy trees. Disturbance history was reconstructed by examining individual tree growth trends. The study plots were further aggregated into five groups based on disturbance history (severity and timing) to evaluate and explain its influence on forest structure. These ecosystems are characterized by a mixed severity disturbance regime with high spatiotemporal variability in severity and frequency. However, periods of synchrony in disturbance activity were also found. Specifically, a peak of canopy disturbance was found for the mid-19th century across the region (about 60% of trees established), with the most important periods of disturbance in the 1820s and from the 1840s to the 1870s. Current stand size and age structure were strongly influenced by past disturbance activity. In contrast, past disturbances did not have a significant effect on current tree density, the amount of coarse woody debris, and regeneration. High mean densities of regeneration with height >50 cm (about 1400 individuals per ha) were observed. Extensive high severity disturbances have recently affected Central European forests, spurring a discussion about the causes and consequences. We found some evidence that forests in the Western Carpathians were predisposed to recent severe disturbance events as a result of synchronized past disturbance activity, which partly homogenized size and age structure and made recent stands more vulnerable to bark beetle outbreak. Our data suggest that these events are still part of the range of natural variability. The finding that regeneration density and volume of coarse woody debris were not influenced by past disturbance illustrates that vastly different past disturbance histories are not likely to change the future trajectories of these forests. These ecosystems currently have high ecological resilience to disturbance. In conclusion, we suggest that management should recognize disturbances as a natural part of ecosystem dynamics in the mountain forests of Central Europe, account for their stochastic occurrence in management planning, and mimic their patterns to foster biodiversity in forest landscapes.

Anthropogenic acidification effects in primeval forests in the Transcarpathian Mts., western Ukraine.

The precipitation chemistry, deposition, nutrient pools and composition of soils and soil water, as well as an estimate of historical deposition of sulphur (S) and inorganic nitrogen (N) for the period 1860-2008, were determined in primeval deciduous and coniferous forests at the sites Javornik and Pop Ivan, respectively. Measured S throughfall inputs of 10 kg ha(-1)year(-1) in 2008 were similar to those estimated for the period 1900-1950 at both sites. The highest estimated S inputs were in the 1980s. Measured bulk deposition of N in 2008 was lower at Pop Ivan (5.6 kg ha(-1)year(-1)) compared to Javornik (12 kg ha(-1)year(-1)). Significantly lower NO(3) deposition was both estimated and measured at Pop Ivan. Higher soil base cation concentrations were observed at well-buffered Javornik underlain by flysch (Ca pool of 2046 kg ha(-1) and base saturation of 29%) compared to Pop Ivan underlain by crystalline schist (Ca pool of 186 kg ha(-1) and base saturation of 6.5%). The soil pool of organic carbon (C) was higher at Pop Ivan (212 t ha(-1)) compared to Javornik (127 t ha(-1)). The C concentration was positively correlated with organic N in the soil (p<0.001) at both sites, but the mass average C/N ratio in the forest floor was lower at Javornik (22) than at Pop Ivan (26). High N leaching of 17 kg ha(-1)year(-1) at the 90 cm depth was measured in the soil water at Javornik, suggesting high mineralization and nitrification rates in old growth deciduous forests in the area. Despite relatively low Al concentrations in the soil water, a low soil water Bc/Al ratio (0.9) (Bc=Ca+Mg+K) was found in the upper mineral soil at Pop Ivan. This suggests that the spruce forest ecosystems in the area are vulnerable to anthropogenic acidification and to the adverse effects of Al on forest root systems.

Patterns of Fraxinus angustifolia in an alluvial old-growth forest after declines in flooding events

The main focus of this paper was the dynamics of Fraxinus angustifolia tree spatial patterns after the frequency of flooding events has markedly declined, especially as regards competition with Carpinus betulus and Acer campestre, the most rapidly expanding species in alluvial hardwood forests in Central Europe. The study was conducted in alluvial forests at the confluence of the Morava and Dyje rivers in the Czech Republic. A pair correlation function was used to describe the variability in tree density. Analyses were carried out for datasets from 1973, 1994 and 2006. Over the study period, F. angustifolia populations were characterised by stagnation in the number of individuals, while the number of C. betulus and A. campestre trees increased. Recruitment rates of F. angustifolia were the lowest of all species with the exception of Quercus robur. Recruits of F. angustifolia showed a strong connection to newly available space after decay of the Q. robur layer. Analysis of the elevational distribution of populations showed an increase in the stand intersection of tree species. In the absence of regular floods, F. angustifolia comes into direct competition with C. betulus and A. campestre, which are more adapted to grow in densely shaded, closed stands.

Biomechanical effects of trees in an old-growth temperate forest: Biomechanical effects of trees

The role of biomechanical effects of trees (BETs) in ecosystem and landscape dynamics is poorly understood. In this study, we aim to (i) describe a widely applicable methodology for quantifying the main BETs in soil, and (ii) analyze the actual frequencies, areas and soil volumes associated with these effects in a mountain temperate old-growth forest. The research took place in the Boubinsky Primeval Forest in the Czech Republic; this forest reserve, predominated by Fagus sylvatica L. and Picea abies (L.) Karst., is among the oldest protected areas in Europe. We evaluated the effects of 4000 standing and lying trees in an area of 10.2ha from the viewpoint of the following features: tree uprooting, root mounding, bioprotection, trunk baumsteins (rock fragments displaced by trunk growth), root baumsteins, stump hole infilling, trunk and root systems displacements, depressions formed after trunk fall, stemwash, and trunkwash. BETs were recorded in 59% of standing and 51% of lying dead trees (excluding the pervasive soil displacement by thickening trunks and roots and the infilling of decayed stumps). Approximately one tenth of the trees showed simultaneous bioprotective and bioerosion effects. Different tree species and size categories exhibited significantly different biomechanical effects. A bioprotective function was the most frequent phenomenon observed, while treethrows prevailed from the viewpoint of areas and soil volumes affected. The total area influenced by the BETs was 342m(2)ha(-1). An additional 774m(2)ha(-1) were occupied by older treethrow pit-mounds with already decayed uprooted trunks. The total volume of soil associated with the studied phenomena was 322m(3)ha(-1), and apart from treethrows, volumes of the living and decaying root systems and bioprotective functions predominated. Other processes were not so frequent but still significant for biogeomorphology. Copyright (c) 2017 John Wiley & Sons, Ltd.

Gradients in Lake Effect Snowfall and Fire across Northern Lower Michigan Drive Patterns of Soil Development and Carbon Dynamics

Soils and forest ecosystems vary predictably along a 145-km transect in northern Lower Michigan. In the east, Entisols support open jack pine stands. In the central transect, weak Spodosols have formed under oak–pine–aspen forests. In the Lake Michigan snowbelt on the west, strongly developed Spodosols occur beneath mesic northern hardwoods. We hypothesized that increasing amounts of snowfall, coupled with decreasing fire frequencies, promote soil development and enhance soil C dynamics at western sites. We also hypothesized that enhanced soil development facilitated greater proportions of broadleaf tree establishment, which in turn accelerates snowmelt rates and further facilitates soil development by enhancing deeper C translocation. Along the transect, we described, sampled, and characterized twelve soils. Soil development increases east to west along the transect, changing most rapidly at the inner margins of the snowbelt, near the coniferous–broadleaf forest ecotone. Coincident with strong soil development in the snowbelt is an increase in soil C storage and cycling. Depth profiles of C, 13C, and Fe- and Al-humus complexes all suggest that snowmelt percolation drives these patterns. Hardwoods produce and cycle more C than coniferous stands to the east and have thicker snowpacks. In the snowbelt, late-lying snowpacks limit spring fires, and large pulses of snowmelt water drive the fresh, soluble C from O horizons deeper, enhancing soil development and fostering ecosystem productivity. Although the current snowbelt, climate, and fire patterns across the peninsula might date only to ≈7,000 cal yr BP, they have nonetheless affected pedogenesis to the point that a major Entisol-to-Spodosol continuum has formed.