Central European Forests Research Articles

Analyzing the effect of silvicultural management on the trade-off between stand structural heterogeneity and productivity over time

This study combined an empirically based simulation with an analysis of the trade-off between structural heterogeneity and stand productivity depending on time, spatial scale, and silvicultural management, whereas volume growth and tree species diversity have been examined in detail, the role of forest structure and its interdependencies with stand productivity has only lately become a stronger research focus. We used the growth simulator SILVA to examine the development of stand structural heterogeneity and its trade-off with stand productivity in age-class versus uneven-aged pure and mixed spruce and beech stands at different spatial scales over 100 years. Those stands were based on typical forest types in Bavaria and were representative of forests in Central Europe. We examined how stand structure and its trade-off with productivity were modified by a multifunctional, a production-oriented, and a set-aside management scenario. The production-oriented management scenario applied to uneven-aged stands led to a reduction in structural heterogeneity per unit of productivity over time. In age-class stands, the production-oriented scenario was able to maintain the initial structural heterogeneity. The structural heterogeneity per unit of productivity increased more strongly with increasing spatial scale in age-class stands compared to uneven-aged stands. Combining forest stand simulation with scenario analyses is an exemplary method for testing the effect of silvicultural management alternatives on forest structure. This approach can later be connected to climate models considering long-term changes in growing conditions and support the planning of multifunctional forests.

The Populations and Habitat Preferences of Three Elm Species in Conditions Prevailing on Plains of Poland

From among the 35–40 elm species existing around the world, three are native to Europe: the wych elm (Ulmus glabra Huds.), the European white elm, (Ulmus laevis Pall.), and the field elm (Ulmus minor Mill.). The populations of these trees have been greatly reduced as a result of a decrease in the total area of riparian forests. Furthermore, for nearly 100 years, they have been destroyed by Dutch elm disease (DED). The main research problems of this study are: what are the habitat preferences of elms growing in a given area; and whether the occurrence of DED depends on the species of elm and the habitat in which it occurs. The results presented here are based on field studies and observations have been supplemented with data from forest inventories. All of the examined elms are definitely more abundant in habitats that are fertile or very fertile and moist, with a neutral or slightly alkaline soil pH. The preference for moist sites is the most evident in the case of U. laevis and the least evident in the case of U. glabra. A slight shift in habitat preferences of the field elm, compared to the white elm, towards less humid conditions was observed. The predominant species of elm in the studied area is currently U. laevis, which was rarely cultivated in forests in the past. In the examined area, the field elm population is clearly on the decline mainly due to the long-term presence of Dutch elm disease. U. glabra is the rarest species in the examined area and most often found on slopes. The current proportions of individual species should be maintained. This paper discusses factors, including ones not connected with DED, that may be responsible for the current state of populations of particular species of elm in forests of Central Europe.

Controlling landscape-scale bark beetle dynamics: Can we hit the right spot?

Outbreaks of spruce bark beetle Ips typographus have devastating effects on European forest landscapes. Salvage removal of windfelled trees is deemed effective to prevent the outbreaks, although adverse effects on ecosystem recovery, ecologically valuable legacies, and unclear economic performance raise concerns about the widespread use of this practice. Here, we formulated a novel management framework aiming for the salvaging of a limited number of windfelled stands with the highest leverage for outbreak risk, potentially replacing the current large-scale uniform treatments. We demonstrated our concept in a Central European forest landscape using the forest disturbance model iLand and a newly developed optimization tool based on graph theory. We simulated the removal of 33% and 66% of windfelled trees in (i) stands randomly distributed on the landscape and (ii) stands identified by the optimization algorithm. Moreover, we tested the effect of (iii) a no-treatment strategy and (iv) complete removal of windfelled trees.We found that the spatially optimized salvaging that aimed to remove 66% of the windfelled trees reduced the level of damage from bark beetles by 55%, whereas the non-optimized treatments, which removed the same volume of windfelled trees, reduced the damage by only 10%. In contrast to the reference treatments, the optimized approaches also retained their efficiency under elevated air temperature, which amplified the outbreaks. Although effects on deadwood retention were variable, the optimized treatments mitigated the economic impacts of the outbreak more effectively. The total loss of 7487 EUR ha−1, incurred without any treatment, was reduced by 36.7%–68.9% (range for 33 % and 66 % salvaging intensity), whereas the loss reduction under the reference treatments was only 27.6%–57.7%.We conclude that the spatially optimized salvaging proposed here can better balance multiple management objectives than the broadly applied uniform treatment, including the reduction of secondary disturbance from bark beetles, deadwood retention and economic goals.

Satellite-based habitat monitoring reveals long-term dynamics of deer habitat in response to forest disturbances.

Disturbances play a key role in driving forest ecosystem dynamics, but how disturbances shape wildlife habitat across space and time often remains unclear. A major reason for this is a lack of information about changes in habitat suitability across large areas and longer time periods. Here, we use a novel approach based on Landsat satellite image time series to map seasonal habitat suitability annually from 1986 to 2017. Our approach involves characterizing forest disturbance dynamics using Landsat-based metrics, harmonizing these metrics through a temporal segmentation algorithm, and then using them together with GPS telemetry data in habitat models. We apply this framework to assess how natural forest disturbances and post-disturbance salvage logging affect habitat suitability for two ungulates, roe deer (Capreolus capreolus) and red deer (Cervus elaphus), over 32yr in a Central European forest landscape. We found that red and roe deer differed in their response to forest disturbances. Habitat suitability for red deer consistently improved after disturbances, whereas the suitability of disturbed sites was more variable for roe deer depending on season (lower during winter than summer) and disturbance agent (lower in windthrow vs. bark-beetle-affected stands). Salvage logging altered the suitability of bark beetle-affected stands for deer, having negative effects on red deer and mixed effects on roe deer, but generally did not have clear effects on habitat suitability in windthrows. Our results highlight long-lasting legacy effects of forest disturbances on deer habitat. For example, bark beetle disturbances improved red deer habitat suitability for at least 25yr. The duration of disturbance impacts generally increased with elevation. Methodologically, our approach proved effective for improving the robustness of habitat reconstructions from Landsat time series: integrating multiyear telemetry data into single, multi-temporal habitat models improved model transferability in time. Likewise, temporally segmenting the Landsat-based metrics increased the temporal consistency of our habitat suitability maps. As the frequency of natural forest disturbances is increasing across the globe, their impacts on wildlife habitat should be considered in wildlife and forest management. Our approach offers a widely applicable method for monitoring habitat suitability changes caused by landscape dynamics such as forest disturbance.

Carbon sequestration of forest soils is reflected by changes in physicochemical soil indicators ─ A comprehensive discussion of a long-term experiment on a detritus manipulation

The interactions of climatic and geochemical factors control soil organic carbon storage capacity and turnover. The comprehensive evaluation of the effect of long-term detritus manipulation on the soil organic carbon, soil-forming processes and the soil physical and chemical properties will help us better understand the carbon sequestration of forest soils. The long-term (19 years) effect of detrital input and removal treatments (DIRT) on physicochemical soil properties were investigated at a Central-European forest site (Síkfőkút, Hungary). In contrast to the results of similar experiments in other parts of the world, the detritus input treatments affected the soil organic carbon and almost all of the soil physicochemical indicators for the upper 15 cm layer. Soil pH, potential acidity and base saturation decreased in the litter removal plots and increased in the detritus doubling treatments. A decrease in organic matter content in the litter removal plots explained the changes in bulk density, as the stability of aggregates also decreased with the decrease of exchangeable bases and organic colloids. In this respect, compared to the other DIRT sites and other similar experiments in the world, our experimental site is considered unique, as it has the highest clay content and the driest climate. We conclude that potential cation exchange capacity and base saturation (exch. Ca) play a fundamental role in predicting the occurrence of the carbon sequestration mechanisms. We suggest to include these parameters into current SOC models.

Edaphoclimatic factors determining sunflower yields spatiotemporal dynamics in northern Ukraine

The climate and soil conditions have a significant impact on sunflower yields. Sunflower yield dynamics in the Central European mixed forests (Polissya) and Eastern European forest-steppe ecoregions in Ukraine from 1991 to 2017 was proved to fit a log-logistic model most adequately. The model has four characteristic parameters: the Lower Limit indicates the lowest level of yield over the study period; the Slope indicates the rate of yield increase over time; the ED50 is the time required to reach half of the maximum yield level and simultaneously the point with the highest rate of yield increase; the Upper Limit shows the highest yield level. The parameters of the yield model are used to meaningfully interpret the causes of yield dynamics. Edaphoclimatic factors account for 34 to 58% of the variation in the yield trend parameters. The soil texture and soil organic carbon (SOC) predominate among the edaphic factors that determine the variability of sunflower yield. Continentality of climate and degree of temperature variability during the growing season are the main climatic determinants of sunflower yield parameters.

Analysis of Qualitative Features of Beech and Oak Trunks as a Determinant of the Quality Assessment

Proper quality assessment of timber requires a certain level of knowledge and overview of technical conditions and correct identification and assessment of the qualitative features of trunks. The ratio of the highest quality classes is decreasing. Therefore, increasing the potential financial resources allocated to forest management could lead to the improvement and increase of this ratio. The objective of the study was to identify the frequency and occurrence of limiting features in the group of non-coniferous beech and oak trunks. A further objective was to classify major factors causing and increasing the frequency of occurrence of such limiting marks. Altogether, 969 beech and oak trunks were assessed in the University Forest Enterprise of the Technical University in Zvolen. The dependences of the size and occurrence of individual qualitative features on the selected factors were statistically assessed using the Pearson correlation coefficient and Cramer’s V; significance was established using χ2 test and a significance level α = 0.05. The most frequently occurring features were sweep, knots, and heart shakes. The results of the comparative and statistical analysis indicate that the management of forest stands and interventions carried out in the forest stands affect the occurrence of the negative features being analyzed the most. However, the conditions of the given site (soil, subsoil, and slope) also play a certain role and can affect the technological aspect of the harvest. The obtained results are valid for the conditions of the University Forest Enterprise of the Technical University in Zvolen; however, they can also be applied in a wider range of similar conditions of Central European forest stands.

Height growth-related competitiveness of oak (Quercus petraea (Matt.) Liebl. and Quercus robur L.) under climate change in Central Europe. Is silvicultural assistance still required in mixed-species stands?

Sessile oak (Quercus petraea (Matt.) Liebl.) and pedunculate oak (Quercus robur L.) play an important role in increasing the resistance of central European forests to severe droughts. But outside their real niche the competitiveness of both oak species can be low in mixed-species stands. This paper examines the height growth of oaks depending on environmental conditions and inter-specific competition. Height growth of trees was analysed using data from forest inventories covering monospecific and mixed-species stands within the German federal state of Bavaria. By means of regression analyses of 23,607 height measurements, we found that site conditions and stand structure have strong effects on the height growth of oak. Summer temperature, water balance in the vegetation period and base saturation were the main explanatory site variables. The first positive effect of summer temperature had no influence at warmer sites with mean summer temperatures above 16.4 °C, while the effect of water balance was positively linear. In addition, stand density modified the height growth of oak in a mainly positive manner. Vertical structure also had a positive effect, which was found for most species compositions, except monospecific stands and oak-hornbeam mixture. In most mixtures, oaks height growth seemed to be less climate-sensitive compared to monocultures. A currently warmer and drier climate seemed to favour the height growth superiority of European beech, whereas it decreased the superiority of Scots pine. The results indicated that even if the climate changes as predicted, the growth of oak will depend upon silvicultural promotion. Our findings can be used to improve regional guidelines for oak silviculture with special regard to climate-sensitive height growth. For example, a regionally delayed introduction of admixed species can reduce silvicultural treatments by ensuring oak vitality in mixed forests at the same time.

Editorial to the thematic issue: Ecological interactions in Central European forest under climate change

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Richness and composition of macrofungi on large decaying trees in a Central European old-growth forest: a case study on silver fir (Abies alba)

The species richness and composition of macrofungi on huge fallen trunks of silver fir (Abies alba) were monitored during a case study in the well-preserved Boubinský prales virgin forest in Czechia. A detailed survey of all macrofungal groups recorded 200 species on 30 trunks within the diameter range of 85–190 cm. This number is very high in the overall context and includes many rare and threatened species. The species-richest groups were corticioids and fleshy saprotrophic fungi. Individual trunks were inhabited by 4–33 species. The species richness was negatively correlated with trunk decay and positively with bark cover, moss cover and trunk length. Simultaneously, it was negatively correlated with increasing time since tree fall, time since tree death and the way of fall, namely its category ‘broken’. Species composition was significantly influenced by decay, bark cover, moss cover, and, to a lesser degree, also by canopy cover, time since fall and time since death. The best trunks in terms of mycobiota rarity and nature conservation were those which died a long time ago but fell to the ground only recently. They have gone through a long phase of slow decay and gradual succession in standing position. As a result, they are inhabited by many distinctive fungi, especially those preferring natural forests. Durandiella gallica, Hohenbuehelia josserandii, Panellus violaceofulvus, Phellinus pouzarii and Pseudoplectania melaena can be considered almost exclusive fir specialists. All these fir-associated fungal species are immediately threatened by the gradual disappearance of firs resulting mainly from ungulate overpopulation, requiring the urgent implementation of appropriate conservation measures. A list of fungi characteristic of wood of silver fir and Norway spruce is presented.

Evaluation of Abiotic Controls on Windthrow Disturbance Using a Generalized Additive Model: A Case Study of the Tatra National Park, Slovakia

Windthrows are the most important type of disturbance occurring in the forests of Central Europe. On 19 November 2004, the strong northeastern katabatic winds caused significant damage and land cover change to more than 126 km2 of spruce forests in the Tatra National Park. The risk of subsequent soil erosion and accelerated runoff has increased in the affected habitats. Similar situations may reoccur this century as a consequence of climate change. A geographical approach and detailed research of the damaged area with more comprehensive statistical analyses of 47 independent variables will help us to obtain a deeper insight into the problem of windthrow disturbances. The results are based on a detailed investigation of the damaged stands, soil, and topography. A comprehensive input dataset enabled the evaluation of abiotic controls on windthrow disturbance through the use of a generalized additive model (GAM). The GAM revealed causal linear and nonlinear relationships between the local dependent quantitative variables (the damage index and the uprooting index) and independent variables (various soil and topography properties). Our model explains 69% of the deviance of the total damage. The distribution of the wind force depended upon the topographical position—mainly on the distance from the slope’s foot lines. The soil properties (mainly the soil skeleton, i.e., rock fragments in stony soils) affect the rate and manner of damage (uprooting), especially on sites with less wind force. Stem breakage with no relation to the soil prevailed in places with high force winds. The largest number of uprooted trees was recorded in localities without a soil skeleton. The spruce’s waterlogged shallow root system is significantly prone to uprooting. The comprehensive research found a significant relationship between the abiotic variables and two different measures of forest damage, and can expand the knowledge on wind impact in Central European forests.

How will a drier climate change carbon sequestration in soils of the deciduous forests of Central Europe?

Global warming is accompanied by increasing water stress across much of our planet. We studied soil biological processes and changes in soil organic carbon (SOC) storage in 30 Hungarian oak forest sites in the Carpathian Basin along a climatic gradient (mean annual temperature (MAT) 9.6–12.1 °C, mean annual precipitation (MAP) 545–725 mm) but on similar gently sloped hillsides where the parent materials are loess and weathered dust inputs dating from the end of the ice age. The purpose of this research was to understand how a drying climate, predicted for this region, might regulate long-term SOC sequestration. To examine the effects of decreasing water availability, we compared soil parameters and processes in three categories of forest that represented the moisture extremes along our gradient and that were defined using a broken-stick regression model. Soil biological activity was significantly lower in the driest (“dry”) forests, which had more than double the SOC concentration in the upper 30 cm layer (3.28 g C/100 g soil ± 0.11 SE) compared to soils of the wettest (“humid”) forests (1.32 g C/100 g soil ± 0.09 SE), despite the fact that annual surface litter production in humid forests was ~ 37% higher than in dry forests. A two-pool SOM model constrained to fit radiocarbon data indicates that turnover times for fast and slow pools are about half as long in the humid soil compared to the dry soil, and humid soils transfer C twice as efficiently from fast to slow pools. Enzyme activity and fungal biomass data also imply shorter turnover times associated with faster degradation processes in the soils of humid forests. Thermogravimetry studies suggest that more chemically recalcitrant compounds are accumulating in the soils of dry forests. Taken together, our results suggest that the predicted climate drying in this region might increase SOC storage in Central European mesic deciduous forests even as litter production decreases.

European beech leads to more bioactive humus forms but stronger mineral soil acidification as Norway spruce and Scots pine – Results of a repeated site assessment after 63 and 82 years of forest conversion in Central Germany

To reduce the effects of extended coniferous monoculture plantations on forest floor and topsoil processes, like amplified acidification or nutrient immobilization in organic layers, small interspersed groups of European beech were planted at the beginning of the 20th century amid large coniferous stands (CS) in Central Germany. Today, these so-called “Green Eyes” (GE) are 82-year old. In our study we focused on two different timelines to investigate the effects of forest conversion on vegetation composition, forest floor and mineral soil properties, encompassing a long-term (>80 year) comparison from tree planting in the 1930s to 2018 and a shorter timeframe nearly spanning 20 years (1999–2018). Since long-term forest conversion experiments (>60 years) across sites sharing a common forest land-use history are scarce, our study allows to contribute to a better evaluation of the long-term effects on changes in soil properties. We linked standard methods assessing soil pH, organic C and total N concentrations as well as stocks as indicators of soil quality changes in forest floor and mineral soil (down to 40 cm depth) to patterns in ground vegetation dynamics (most GE were characterized only by a few herbaceous species). Our results exhibited an effect of forest conversion on the activation in forest floor turnover resulting in increased turnover rates in the GE (GE contain only half of the forest floor OM of CS), hence forming more bioactive humus forms (mull, moder) and a noticeable higher forest floor pH (+0.6 units) compared to CS. The OC translocation from the forest floor into the topsoil is higher under GE (+0.7% OC content), probably building up a stable SOC pool hence contributing to C sequestration. The positive effects of European beech on forest floor quality are related to a stronger acidification of the subsoil during the past 20 years (-0.5 pH units). The base pump effect (uptake of Ca2+, Mg2+, K+ and assimilation into tree biomass in exchange release of H+) in GE led to more acidic conditions (-0.2 pH units) in the deeper mineral soil compared to CS. This bio-acidification may serve as one reason for subsoil acidification, as observed in our study, pointing out that mineral soil acidification is still an important issue in central European forests. Future restoration of soil base cation pools will still depend on the rate of bio-acidification, on the amount of acidifying air pollutant (and base cation) depositions and on forest management practices (e.g. intensity of biomass removal, soil regeneration-oriented liming).

Scots pine forest in Central Europe as a habitat for Harmonia axyridis: temporal and spatial patterns in the population of an alien ladybird

Abstract Understanding of habitat favourability has wide relevance to the invasion biology of alien species. We studied the seasonal dynamics of the alien ladybird Harmonia axyridis (Coleoptera: Coccinellidae) in monoculture Scots pine forest stands in south-west Slovakia, Central Europe, from April 2013 to March 2015. Adult H. axyridis were collected monthly across seven randomly selected pine stands of different ages and canopy closure, from the lower branches of pine trees, and larvae were recorded qualitatively. Adults were recorded all year round, most abundantly in November and least abundantly in February. The relationship between the abundance of H. axyridis and selected forest stand characteristics was modelled using the negative binomial Generalized Additive Model with penalized spline component in month (seasonality) effect, year, canopy closure and age effects and the random effect of forest stand (sample area effect). The abundance of H. axyridis was significantly influenced by the age of stand and seasonality (with month granularity) for both closed and open canopy stands, whereas the effects of canopy closure and sample area were not significant. The bimodal pattern of seasonal dynamics of H. axyridis on Scots pine was common for closed and open canopy stands, with two peaks reflecting the cyclic movement of the species from and to overwintering sites. Harmonia axyridis utilized certain pine stands preferably for foraging during the growing season and certain stands for refuge during winter. The ladybirds were found in highest numbers in the 15 year old closed canopy stand (overwintering site). The occurrence of both adults and larvae in most stands indicated a suitability of Scots pine forest for ladybird breeding. The model of year-round dynamics of H. axyridis has been presented for the first time within the invaded range of the ladybird in Europe.

Large-scale early-wilting response of Central European forests to the 2018 extreme drought.

The combination of drought and heat affects forest ecosystems by deteriorating the health of trees, which can lead to large‐scale die‐offs with consequences on biodiversity, the carbon cycle, and wood production. It is thus crucial to understand how drought events affect tree health and which factors determine forest susceptibility and resilience. We analyze the response of Central European forests to the 2018 summer drought with 10 × 10 m satellite observations. By associating time‐series statistics of the Normalized Difference Vegetation Index (NDVI) with visually classified observations of early wilting, we show that the drought led to early leaf‐shedding across 21,500 ± 2,800 km2, in particular in central and eastern Germany and in the Czech Republic. High temperatures and low precipitation, especially in August, mostly explained these large‐scale patterns, with small‐ to medium‐sized trees, steep slopes, and shallow soils being important regional risk factors. Early wilting revealed a lasting impact on forest productivity, with affected trees showing reduced greenness in the following spring. Our approach reliably detects early wilting at the resolution of large individual crowns and links it to key environmental drivers. It provides a sound basis to monitor and forecast early‐wilting responses that may follow the droughts of the coming decades.

The list of forest affinities for animals in Central Europe – A valuable resource for ecological analysis and monitoring in forest animal communities?

Since 2011 a list of the forest affinities of all forest species of vascular plants, bryophytes, and ferns known from Germany, is available. Recently, the first comparable lists of the forest affinities of animal species were published. These lists include a categorization of forest affinities for all species of Crassiclitellata: Lumbricidae (earth worms), Araneae (spiders), Opiliones (harvestmen), Pseudoscorpiones (pseudoscorpions), Hemiptera: Heteroptera (true bugs), Coleoptera (beetles), Hymenoptera: Aculeata (ants, bees, wasps), Lepidoptera: Macrolepidoptera (butterflies, moths partly) and Aves (birds) known from Germany. The lists are a valuable resource that have the potential to add new layers of discovery to analyses of forest animal communities. Here we present a summary of the lists. We also re-analyze existing data sets in light of forest affinities to highlight possible applications of these lists in ecological assessments and characterizations of animal communities in central European forests. We show that the forest affinity lists can add valuable new insights for analyzing community structure, temporal community dynamics or communities across ecological gradients, represent an important tool for developing conservation strategies, and can be used to clear a dataset of chance findings of allochtonous specimens prior to analysis.

Stand age affects fungal community composition in a Central European temperate forest

Fungi are key mediators of ecosystem processes in temperate forests. Hence, understanding of fungal community development is central to better understand the mechanisms driving shifts in ecosystem processes during forest succession. We studied fungal communities in soil, rhizosphere and roots in a Central European forest chronosequence (1–137 years) dominated by Fagus sylvatica and Picea abies. We assessed whether and how fungal community composition and productivity change along the forest age gradient. Stand age did not have any significant effect on fungal ergosterol content but community composition shifted with the stand age. In particular, the composition of the community of root-associated ectomycorrhizal fungi responded to stand age. Relative abundances of different fungal ecological guilds did not change with forest age and ectomycorrhizal exploratory types were not good predictors of community dynamics. Our results suggest that the stand age effect on community composition may be driven by changes in nutrient supply provided by plant hosts to root-associated fungi.

Natural dynamics of temperate mountain beech-dominated primary forests in Central Europe

Natural disturbances are key factors in the formation of forest ecosystem structure. Evaluation of the spatial and temporal extent of disturbance regimes is critical for understanding forest dynamics, forest structural heterogeneity, and biodiversity habitats. Quantifying disturbance regimes is therefore imperative for appropriate management of forests and protected areas. However, natural disturbance regimes have rarely been assessed using dendrochronological methods on a regional scale across primary mixed beech-fir forest stands - one of the dominant forest vegetation types in Europe. To study the natural disturbance regimes of beech-dominated mixed-forest stands, we established 42 permanent study plots with an area of 0.1 ha across three primary forest stands in the Western Carpathians, a region that still contains large areas of primary forest. We reconstructed each stand-level disturbance history using a tree-ring based approach. The temporal synchronicity of disturbance events was then evaluated by delineating stand-level disturbance events using a kernel density function, and through the detection of plot-level disturbances with severities greater than 10 percent. The results obtained from the chronologies showed substantial variability in time and space, especially in the mid-19th century. Low- and moderate-severity plot-level disturbance events were most common, but high- and extremely high-severity plot-level disturbance events also occurred. The observed spatial and temporal variability suggests that the beech-dominated forests were primarily driven by mixed-severity disturbance regimes, with windstorms as the main disturbance agent.This reconstruction of the disturbance regime provided unique insight into the scale of mortality processes in these beech-dominated mixed forests. This information can help guide ecological forestry in areas where both wood production and biodiversity preservation are simultaneous goals, such as by employing more spatiotemporally-complex silvicultural systems that resemble natural disturbance patterns and facilitate heterogeneous forest structures.

Spatial variability of forest floor and topsoil thicknesses and their relation to topography and forest stand characteristics in managed forests of Norway spruce and European beech

Soils play a significant role in climate regulation, especially due to soil organic carbon (SOC). The SOC pool is therefore modeled for various environments, and forest floor and topsoil thicknesses are important parameters for most of these models as they store most of the SOC. However, the forest floor and topsoil thicknesses show high spatial variability which is a result of multiple factors which are not agreed upon among scientists. Out of these factors, we choose topography parameters (elevation, slope, and topography wetness index) and forest stand characteristics (stand age, dominant tree species, and forest floor cover), and soil moisture, and we analyzed their relationship to the forest floor and topsoil thicknesses. The study was performed in a managed submontaneous forest in Central Europe dominated by Picea abies (L.) Karsten with small patches of Fagus sylvatica L. or other species. The thicknesses of the O horizons (Oi, Oe, Oa) and topsoil were measured at 221 sampling pits. Geographically weighted regression showed that the spatial variability of the overall forest floor plus topsoil thickness (OA) is responsible for 8% of its variability. The thickness of the OA is the most strongly controlled by forest floor cover explaining approximately 6% of its variability and soil moisture explaining 2–6% of the variability. The Oi + Oe horizon thickness is controlled only by forest floor cover explaining 10.7% of its variability, and the thickness of Oa + A horizon can be explained mainly by soil moisture in mineral horizon explaining 9% of the variability.

Characteristics of small anthropogenic landforms resulting from historical charcoal production in western Connecticut, USA

Relict charcoal hearths (RCHs) are anthropogenic geomorphic features with an average diameter of 12 m found in many forests of Central Europe and in the eastern USA wherever pre-coal iron production took place or other industries demanded the production of charcoal. To expand the knowledge about their geoarchaeological significance and their legacy effect on soil properties and forest ecosystems, we propose a method for a generalized description of soil stratigraphy on RCHs. We studied 154 soil profiles at 52 RCH sites alongside two 1 km transects in Litchfield County, Connecticut, USA. The sites can be classified based on the slope inclination, with sites on <4° mostly having a single-layered stratigraphy and an elevated circular shape, while sites on slopes >4° mostly are built as levelled and multilayered platforms. The latter have two or more charcoal rich technogenic Auh-layers separated by intermediate Auh-layers mostly consisting of mineral substrate. Based on average layer thicknesses and their dependence on the sites slope inclinations, we propose a model with two idealized RCH shapes with slope controlled properties that allow for an easy computation of site diameters and elemental stocks. With ongoing advances in remote sensing of RCH sites, our proposed model can help to further understand the effects of historic land use on a landscape scale.