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Background: We analyze the forest carbon stock development following the recent historically unprecedented dieback of coniferous stands in the Czech Republic. The drought-induced bark-beetle infestation resulted in record-high sanitary logging and total harvest more than doubled from the previous period. It turned Czech forestry from a long-term carbon sink offsetting about 6% of the country's greenhouse gas emissions since 1990 to a significant source of CO2 emissions in recent years (2018–2021). In 2020, the forestry sector contributed nearly 10% to the country's overall GHG emissions. Using the nationally calibrated Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) at a regional (NUTS3) spatial resolution, we analyzed four scenarios of forest carbon stock development until 2070. Two critical points arise: the short-term prognosis for reducing current emissions from forestry and the implementation of adaptive forest management focused on tree species change and sustained carbon accumulation. Results: This study used four different spruce forest dieback scenarios to assess the impact of adaptive forest management on the forest carbon stock change and CO2 emissions, tree species composition, harvest possibilities, and forest structure in response to the recent unprecedented calamitous dieback in the Czech Republic. The model analysis indicates that Czech forestry may stabilize by 2025 Subsequently, it may become a sustained sink of about 3 Mt CO2 eq./year (excluding the contribution of harvested wood products), while enhancing forest resilience by the gradual implementation of adaptation measures. The speed of adaptation is linked to harvest intensity and severity of the current calamity. Under the pessimistic Black scenario, the proportion of spruce stands declines from the current 43–20% by 2070, in favor of more suited tree species such as fir and broadleaves. These species would also constitute over 50% of the harvest potential, increasingly contributing to harvest levels like those generated by Czech forestry prior to the current calamity. The standing stock would only be recovered in 50 years under the optimistic Green scenario. Conclusion: The results show progress of adaptive management by implementing tree species change and quantify the expected harvest and mitigation potential in Czech forestry until 2070. [ABSTRACT FROM AUTHOR]

Mountain forests are more prone to environmental predispositions (EPs) than submountain ones. While remote sensing of mountain forests enables instantaneous damage mapping, the investigation of the causes requires field data. However, a local field or regionally modeled environmental characteristics influence remote data evaluation differently. This study focused on the evaluation of EPs effects damaging mountain forests between various spatial resolutions during environmental change. The evaluation was divided into managed and natural forests in the Hrubý Jeseník Mts. (Czech Republic; 240–1491 m a.s.l.; 50.082°N, 17.231°E). Damage was assessed through the discrimination analysis of the normalised difference vegetation index (NDVI) by MODIS VI during alternating drought and flood periods 2003–2014. The local environmental influence was assessed using the discrimination function (DF) separability of forest damage in the training sets. The regional influence was assessed through map algebra estimated via the DF and a forest decline spatial model based on EPs from differences between risk growth conditions and biomass fuzzy sets. Management, EPs and soil influenced forest NDVI at different levels. The management afflicted the NDVI more than the EPs. The EPs afflicted the NDVI more than the soil groups. Strong winters and droughts had a greater influence on the NDVI than the flood events, with the winter of 2005/2006 inverting the DF direction, and the 2003 drought increasing differences in managed forest biomass and decreasing differences in natural forest biomasses. More than 50% of declining managed forests in the training sets occurred on Leptosols, Podzols and Histosols. On a regional scale, the soil influence was eliminated by multiple predispositions. The EPs influenced 96% of natural forest and 65% of managed forest, though managed forest damage was more evident. The mountain forest NDVI decline was dependent on both management and risk predispositions. [ABSTRACT FROM AUTHOR]

Intensive forest and agroforestry management has greatly reduced the biodiversity of saproxylic organisms. Large trees are one of the most important refuges of saproxylic beetles. These large trees that grow outside and inside the forest are declining in the wider landscape. Heritage trees are one of the essential groups of beneficial trees in the landscape. We investigated saproxylic beetles associated with 35 selected oak heritage trees in Litovelské Pomoraví in the eastern Czech Republic. The study aimed to investigate the distribution of saproxylic beetles on trees growing inside or at the edge of forest stands, or on free-growing heritage trees. The other studied variables were the height, DBH, and light condition (sunny or shady) of heritage trees. The results showed that sunny habitats were the only significant factor found for all saproxylic species. However, the significance of increasing tree trunk dimension was found for the endangered species. Diversity indices q = 0 (species richness) and q = 1 (exponential of Shannon entropy index) were also higher for sunny trees, while solitary trees showed a high Shannon index value despite the low number of samples. Redundancy analysis of saproxylic species showed that the preferred habitats of most species were sunny massive solitary oaks. The results indicated that strictly protected heritage trees scattered in the landscape are crucial sanctuaries for many species—especially in landscapes where there are not enough suitable habitats for saproxylic beetles. Finding, conserving, and protecting these rare types of massive trees in the landscape has a significant impact on the conservation of saproxylic beetle biodiversity. [ABSTRACT FROM AUTHOR]

Extreme tree growth reductions represent events of abrupt forest productivity decline and carbon sequestration reduction. An increase in their magnitude can represent an early warning signal of impending tree mortality. Yet the long‐term trends in extreme growth reductions remain largely unknown. We analyzed the trends in the proportion of trees exhibiting extreme growth reductions in two Central‐European conifer species—Pinus sylvestris (PISY) and Picea abies (PCAB)—between 1901 and 2018. We used a novel approach for extreme growth reduction quantification by relating their size to their mean recurrence interval. Twenty‐eight sites throughout Czechia and Slovakia with 1120 ring width series representing high‐ and low‐elevation forests were inspected for extreme growth reductions with recurrence intervals of 15 and 50 years along with their link to climatic drivers. Our results show the greatest growth reductions at low‐elevation PCAB sites, indicating high vulnerability of PCAB to drought. The proportions of trees exhibiting extreme growth reductions increased over time at low‐elevation PCAB, decreased recently following an abrupt increase in the 1970–1980s at high‐elevation PCAB, and showed nonsignificant trends in high‐ and low‐elevation PISY. Climatic drivers of extreme growth reductions, however, shifted over time for all site categories as the proportion of low‐temperature‐induced extreme growth reductions declined since the 1990s, whereas events caused by drought consistently increased in frequency during the same period. We observed higher growth volatility at the lower range of distribution compared with the upper range margin of PISY and PCAB. This will undoubtedly considerably impact tree growth and vitality as temperatures and incidence of drought in Central Europe are expected to further increase with ongoing climate change. [ABSTRACT FROM AUTHOR]

Heavy thinning is supposed to be helpful for maintaining more favorable water balance in forest stands, and thus mitigate impact of drought episodes. To investigate impact of thinning on topsoil (10–13 cm) moisture conditions, a two-year soil sampling campaigns were conducted in 2019 and 2020. The soil moisture was calculated using a water-weight loss approach based on dry/fresh sample weight ratio. The samples were collected using metal capsules of known weight from totally 8–9 experimental series monthly during growing seasons of 2019 and 2020, respectively. Each series included thinned and un-thinned young growth stands of Norway spruce monoculture, spruce mixed with broadleaved tree species and mixture of sycamore maple with rowan. However, the statistically significant differences were not found in topsoil moisture between thinned and un-thinned young growth stands, thinned ones showed slightly better water balance conditions during both investigated years. Reduced number of trees and canopy closure had not depleted water throughout evaporation from upper soil profile. Therefore, thinning of young growth should be recommended especially at drought-endangered sites. Forest health decline and following die-off are exhibited in large areas of monospecific stands of Norway spruce and Scots pine in the Czech Republic. This development is attributable to shifts of conditions such as high air temperatures in growing seasons and different distribution of precipitation amounts over year, which resulted in hydrological drought in 2015–2019. Thinning is a deliberate measure that helps us control future stability, health and resilience of young forest stands and also impacts on species composition, environment and nutrient cycle in the stands. Heavy thinning is supposed to affect hydrological balance as interception is reduced (lower LAI) and more soil water is expected to be available for the trees left on site. On the other hand, such thinning intensity can increase evaporation from inside the stands and it also increases temperature amplitudes. The drought stress is even attributable to increased transpiration rates from released trees in case the soil below canopy has been dry for a long time. If true frequently, one can doubt a usefulness of heavy thinning at drought-endangered forest sites. This article deals with topsoil moisture below thinned thickets of tree species that were compared with moisture conditions below unthinned thickets. The objective of the study addressed a research question whether the thinning affected availability of water in soil, and thus proved a beneficial effect of the heavier thinning on the young drought-endangered forest stands. The sampled stands were monospecific spruce, spruce mixed with other, mainly broadleaved tree species and sycamore maple with rowan (Table 2). The thinning aimed at releasing crop trees of better quality and removal of both the unhealthy ones and wolf broadleaves; the thinned treatment was always accompanied with the unthinned one. 10–13 cm mineral topsoil samples (20 per thinned-unthinned series i.e. 10 per the treatment, see Table 3) were taken monthly in May-September periods in 2019–2020. Larger stones were excluded from the samples, and each sample was placed into metal capsules (of known weight) and covered with lid. The closed capsules were then delivered to laboratory where a water weight loss was measured as ratio of dry (dried at 105 °C) and fresh sample weights; this allowed us to determine a soil sample moisture. Arithmetic means were calculated from 10 values representing thinned and unthinned moisture conditions. The differences were tested using a pair t-test and 95% confidence intervals of difference were computed using R 3.6.3 (R Core Team 2020). In 2019, topsoil moisture was affected negatively by low precipitation at depth of 10–13 cm; minimum values were shown in July. Following 2020 showed more favorable conditions with maximal values in May and July. Soil moisture showed also higher variability in 2020 compared to 2019 (Fig. 1). The differences between control and thinned treatments were very small and even negligible. In 2019, the sites benefited from thinning slightly except for May values when 0.4% higher soil moisture was found below unthinned canopy. No statistically significant (α = 0.05) differences excepting for the thinned treatment in September (1.5% higher moisture, p = 0.02) were found in 2019. The topsoil moisture was 0.6% higher insignificantly (p = 0.27; 95% confidence interval 0.6 ± 1.1 %) under thinned treatments in 2019. Next year, the soil moisture values exhibited small differences reflecting also benefit from thinning; the only zero difference was shown in August. The highest moisture attributable to removal of trees amounted 1.8% higher moisture compared to control in July. No statistically significant (α = 0.05) differences were found significant though July values were at limit of significance (p = 0.05). The topsoil moisture was 0.9% higher insignificantly again (p = 0.16; 95% confidence interval 0.9 ± 1.3 %) under thinned treatments in 2020. Based on the two-year measurement campaign and data analysis it can be concluded: • More favorable precipitation conditions of 2020 affected 10–13 topsoil moisture values positively compared to precipitation-poorer 2019. • The topsoil moisture below thinned thickets showed slightly higher values compared to conditions without thinning; the differences were found insignificant mostly. • Removal of trees and following broken canopies, however, did not show depleted topsoil water due to higher evaporation from exposed forest floor surface. The early thinning of the thickets should not, therefore be ignored at drought-endangered sites. [ABSTRACT FROM AUTHOR]

Magnesium isotope ratios (26Mg/24Mg) can provide insights into the origin of Mg pools and fluxes in catchments where Mg sources have distinct isotope compositions, and the direction and magnitude of Mg isotope fractionations are known. Variability in Mg isotope compositions was investigated in three small, spruce-forested catchments in the Czech Republic (Central Europe) situated along an industrial pollution gradient. The following combinations of catchment characteristics were selected for the study: low-Mg bedrock + low Mg deposition (site LYS, underlain by leucogranite); high-Mg bedrock + low Mg deposition (site PLB, underlain by serpentinite), and low-Mg bedrock + high Mg deposition (site UDL, underlain by orthogneiss). UDL, affected by spruce die-back due to acid rain, was the only investigated site where dolomite was applied to mitigate forest decline. The δ26Mg values of 10 catchment compartments were determined on pooled subsamples. At LYS, a wide range of δ26Mg values was observed across the compartments, from -3.38 ‰ (bedrock) to -2.88 ‰ (soil), -1.48% (open-area precipitation), -1.34 ‰ (throughfall), -1.19 ‰ (soil water), -0.99 ‰ (xylem), -0.95 ‰ (needles), -0.82 ‰ (bark), -0.76 ‰ (fine roots), and -0.76 ‰ (runoff). The δ26Mg values at UDL spanned 1.32 ‰ and were thus less variable, compared to LYS. Magnesium at PLB was isotopically relatively homogeneous. The δ26Mg systematics was consistent with geogenic control of runoff Mg at PLB. Mainly atmospheric/biological control of runoff Mg was indicated at UDL, and possibly also at LYS. Our sites did not exhibit the combination of low-δ26Mg runoff and high-δ26Mg weathering products (secondary clay minerals) reported from several previously studied sites. Six years after the end of liming at UDL, Mg derived from dolomite was isotopically undetectable in runoff. [ABSTRACT FROM AUTHOR]

Floodplain forests are very complex, productive ecosystems, capable of storing huge amounts of soil carbon. With the increasing occurrence of extreme events, they are today among the most threatened ecosystems. Our study's main goal was to assess the productivity of a floodplain forest located at Lanžhot in the Czech Republic from two perspectives: carbon uptake (using an eddy covariance method) and stem radius variations (using dendrometers). We aimed to determine which conditions allow for high ecosystem production and what role drought plays in reducing such production potential. Additionally, we were interested to determine the relative soil water content threshold indicating the onset and duration of this event. We hypothesized that summer drought in 2018 had the most significant negative effects on the overall annual carbon and water budgets. In contrast with our original hypothesis, we found that an exceptionally warm spring in 2018 caused a positive gross primary production (GPP) and evapotranspiration (ET) anomaly that consequently led in 2018 to the highest seasonal total GPP and ET from all of the investigated years (2015–2018). The results showed ring-porous species to be the most drought resistant. Relative soil water content threshold of approximately 0.45 was determined as indicating the onset of drought stress. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'. [ABSTRACT FROM AUTHOR]

The problem of municipalities under 200 inhabitants is discussed. There are 1,500 such municipalities (24%) in the Czech Republic. Many of them came to existence after 1989 when the independence of communes was considered part of the democratisation process regardless of the population number. This paper aims at a statistical evaluation of municipalities with fewer than 200 inhabitants and presents their geographical distribution, demographic development and analysis of their aging. In general, 70% of these very small municipalities have been growing since 2001. The smallest of them have the highest percentage of the population decline and are the most endangered by aging. Very small municipalities with the highest population growth are situated mainly in the vicinity of larger towns, the ones with the highest population decline are located mainly in peripheral areas at the border of regions. [ABSTRACT FROM AUTHOR]

• Species dependent on dead or decaying wood have been replaced by the xylophagous and floricolous species after forest logging. • Environmental filtering determined species composition before and stochastic factors were important after forest logging. • Αlpha diversity was highest during the first year and β-diversity was highest during the second year after logging. Xerothermophilous beetles are one of the endangered ecological groups of animals, mainly because of the loss of suitable habitats for their development. Many species of these beetles are associated with specific light conditions. Those preferring higher insolation levels may find such conditions in coppices. Coppicing is a type of forest management with a long history, which allowed the survival of many species in the European landscape. After WWII coppicing management was widely abandoned and coppices were transformed into high forest, which caused a significant decline in forest biodiversity. In the Podyjí National Park at the border of Czechia and Austria, coppicing was re-established in two neglected coppices by cutting trees on areas of approximately one hectare in the winter of 2015/2016 to support heliophilous and endangered species of plants and animals. We carried out a study in these two areas by using flight interception traps during the year before the logging (2015), and two years after the logging (2016 and 2017). We analysed the effect of the logging and the following succession on beetle assemblages by comparing beetle taxocoenoses before and after logging. The creation of the clearings in closed-canopy forests had a positive effect on overall species richness and supported threatened species of beetles. We revealed that unlike α-diversity, which was highest during the first year after logging, spatial differentiation of the assemblage (β-diversity) was highest during the second year after logging. Co-occurrence analysis showed that beetle assemblages tended to co-occur more than expected by chance during all study years, indicating shared environmental preferences. On the other hand, after logging the species co-occurrence pattern was closer to random species distribution, showing that dispersal ability and random immigration also play important role in assembly processes. [ABSTRACT FROM AUTHOR]

• Most of the identified rain-on-snow events caused negligible or low runoff at a catchment scale. • Hydrometeorological characteristics and occurrence of ROS differed significantly between both mountain ranges. • Most of the ROS events resulting in high runoff occurred during early winter (Nov–Dec). • Event rainfall is the main driver of high runoff, while temperature has a secondary role. Rain-on-snow (ROS) events influence the hydrological regime of rivers in regions with seasonal snow cover. Although ROS events are often related to floods, they do not always cause severe runoff. During ROS, the snowpack has an ambiguous effect on runoff generation; it can either store a significant portion of rain or amplify runoff by additional snowmelt. There is a need to understand under what circumstances ROS events produce runoff. We analysed eleven years of hourly meteorological, snow water equivalent and streamflow data from 15 catchments located in two mountain ranges in Czechia. We identified 611 ROS events which were further analysed and classified using selected meteorological, snow and runoff indices. The analysis of the runoff response of all ROS events revealed that only 5% of them resulted in high runoff exceeding the 1-year return period, but most of the events (82%) did not cause any significant runoff increase. Employing self-organising maps enabled us to categorise the events and better understand what combination of hydrometeorological characteristics leads to various runoff responses. High volumes of rain together with low snow cover were identified as important factors in the generation of high runoffs. In contrast, a deep and extended snowpack affected by rain under low air temperatures usually caused lower runoffs. The results of this study showed the importance of the snowpack, which can often prevent extreme runoff even when a large amount of rainfall occurs. Understanding the hydrological regime of ROS is becoming even more important with the ongoing decline of the snowfall fraction and subsequent changes in snow storage. [ABSTRACT FROM AUTHOR]

The high contents of soluble and exchangeable aluminum (Al) in soils are believed to be main factors of forest damage in large areas. Krkonoše National Park, in the Czech Republic, is one of the most damaged areas in Central Europe, although the industrial emissions have declined in the past years. The purpose of this work was to evaluate the present concentration of soluble and exchangeable Al in some soils of that area, with different degrees of forest decline. The total Al concentration in water extracts was found to range within the limits 0.022–0.102 mM. According to the commonly used criteria, these values do not exceed the limit of toxicity for most plant species. Aluminum compounds in water extracts are represented predominantly by Al organic complexes and Al polymers. The percentage of the most toxic for plants, Al monomeric hydroxocomplex, ranges within the limits 0–52% of the total Al concentration and is higher in water extracts from the upper parts of the solum as compared with those from the subsoils, in compliance with the increase in pH values down the profile. The molar ratios of calcium (Ca)/Al and (Ca+Mg+K)/Al in water extracts exceed 1, but no clear relation with the forest status is found. The content of exchangeable Al is instead very high, especially in mineral horizons, and the lowest ratios between Ca or the sum of base cations and Al in the exchange complex occurs under the most degraded forest stands. [ABSTRACT FROM AUTHOR]

• Bark stripped trees were studied from the point of extent of damage, production characteristics and radial growth in relation to climatic factors. • The stand volume of heavily damaged trees was 50–71% lower compared to healthy trees. • The vertical stem decay reached maximally up to 4.5–6.0 m (mean 1.9–3.1 m) with the mean speed of vertical spreading of 5.7–9.6 cm yr−1. Decayed wood accounted for 30–39% of the stem volume. Bark stripping damage and the resultant stem rot to Norway spruce (Picea abies [L]. Karst), one of the most important tree species, poses a serious problem for forest management in Europe. Our research objective was to determine the effect of bark stripping, the subsequent rot decay and the impact of climatic factors in young (42–49 years) spruce stands. Moreover, we compared the differences between damage caused by red deer (Cervus elaphus L.) and sika deer (Cervus nippon Temminck). In all the cases studied, game damage was lower in forest stands when caused by sika deer (SD − 77.3%) compared to red deer (RD − 88.8%); 27.8% (SD) – 32.0% (RD) of stem circumference was damaged in average. Damaged trees showed higher growth variability and were more sensitive to a lack of precipitation and droughts, while air temperature had a higher effect on the growth of healthy trees. The initial game damage was observed in the 11 (SD) – 14 (RD) year of the mean tree age. The stem volume was lower by 25% (SD) – 28% (RD) in lightly damaged trees, and 50% (SD) – 71% (RD) in heavily damaged trees compared to healthy trees. The vertical stem decay reached a maximum of up to 4.5 m (SD) – 6.0 m (RD) (mean 1.9–3.1 m) with the mean speed of vertical spreading of 5.7 cm yr−1 (SD) – 9.6 (RD) cm yr−1. The mean decayed wood accounted for 30% (SD) – 39% (RD) of the stem volume. The peripheral stem damage by bark stripping and the age of the first occurrence were significant factors in predicting damaged crosscut area and vertical rot spreading in the stem. During this time of climate change, the stability of damaged spruce stands has been significantly disturbed by deer game. [ABSTRACT FROM AUTHOR]

Scots pine (Pinus sylvestris L.) is a widespread tolerant forest tree-species; however, its adaptability to environmental change differs among sites with various buffering capacity. In this study, we compared the spatial effects of aridity index (AI) and nitrogen deposition (ND) on biomass density in natural and man-made pine stands of differing soil fertility using geographically weighted multiple lag regression. Soil fertility was defined using soil series as zonal trophic (27.9%), acidic (48.2%), gleyed (15.2%) and as azonal exposed (2.5%), maple (2.4%), ash (0.8%), wet (2.1%) and peat (0.9%) under pine stands in the Czech Republic (Central Europe; 4290.5 km2; 130–1298 m a.s.l.). Annual AI and ND in every pine stand were estimated by intersection between raster and vector from 1 × 1 km grid for years 2000, 2003, 2007 and 2010 of severe non-specific forest damage spread. Biomass density was obtained from a MODIS 250 × 250 m raster using the enhanced vegetation index (EVI) for years 2000–2015, with a decrease in EVI indicating non-specific damage. Environmental change was assessed by comparing predictor values at EVI time t and t +λ. Non-specific damage was registered over 51.9% of total forest area. Less than 8.8% of damaged stands were natural and the rest (91.2%) of damaged stands were man-made. Pure pine stands were more damaged than mixed. The ND effect prevailed up to 2007, while AI dominated later. Temporal increasing ND effect under AI effectiveness led to the most significant pine stand damage in 2008 and 2014. Predictors from 2000 to 2007 afflicted 58.5% of non-specifically damaged stands at R2 0.09–0.76 (median 0.38), but from 2000 to 2010 afflicted 57.1% of the stands at R2 0.16–0.75 (median 0.40). The most damaged stands occurred on acidic sites. Mixed forest and sustainable management on natural sites seem as effective remediation reducing damage by ND. Image 1 • We mapped relationship of aridity and N-deposition with biomass of damaged pine stands. • The relationship was investigated through spatial regression. • N-deposition highlights effect of aridity on damaged pine stands. • Pure pine stands are damaged more than mixed stands. • The damage reduction depends on stand mixing and sustainable management. Nitrogen deposition site-specifically highlights decline of pine biomass vulnerable to drought. [ABSTRACT FROM AUTHOR]

• Old coppices in steppic oak forests have high biodiversity. • Establishment of oak plantations has profound effects on biodiversity. • Site preparation and competitive exclusion in young stands may be more detrimental than clear-cutting. • Preservation of old coppices combined with traditional management may aid conservation. Forest vegetation is dominated by long-lived species in the tree layer, which facilitates its relatively high inertia and ability to conserve traces of its history in its structure and species composition. Central European lowland forests have been the subject of diverse human use for millennia and some of the present stands still show remnants of historical management forms practised before the onset of modern forestry. In the past decades, biodiversity decline has become a major concern, and restoration of historical uses has been proposed as a nature-friendly alternative for forest management. We explored the consequences of the transformation of an old oak coppice, historically linked to ancient wood pasture system, to oak plantation. We focused on vascular plant species richness and differences in ecological spectra of the plant assemblages, with the goal of evaluating the consequences for biodiversity conservation and identifying possible environmental drivers behind the observed patterns. The study was performed in the best preserved complex of lowland steppic oak forests in the Czech Republic, protected as a Site of Community Importance. We fully inventoried plant species in 135 oak stands classified into three management-age classes: (1) clear-cuts, (2) young growth stands after area-wide site preparation, and (3) old growth stands. For some analyses, old growth stands were divided into those showing signs of past coppicing and the others. We found that species richness was the highest in clear-cuts, the lowest in young growth stands, and intermediate in old growth stands. Clear-cuts showed the highest uniqueness in species composition, with a high share of ruderal species. Young growth stands showed the lowest uniqueness, with a high proportion of competitive species. Old growth stands showed intermediate uniqueness and the coppiced ones had a high share of stress-tolerant species, often of high conservation value. While it is hardly surprising that the establishment of oak plantations has profound effects on biodiversity, we suggest that clear-cutting itself may not be a key issue. Destructive site preparation in clear-cuts, and competition for resources in dense young oak stands are suggested as the main factors threatening the survival of ancient biota of steppic oak forests in our study area. In contrast, continuity of site conditions in formerly coppiced old growth stands facilitates species survival. We suggest that restoration of historical management forms such as coppicing and wood pasture may support this continuity. Where oak planting is still applied, we advise minimising site preparation and applying early thinning of young growth stands. [ABSTRACT FROM AUTHOR]

Central European forests suffered from severe, large-scale atmospheric depositions of sulfur and nitrogen due to coal-based energy production during the 20th century. High deposition of acid compounds distorted soil chemistry and had negative effects on forest physiology and growth. Since 1994, continuous data on atmospheric deposition and stream runoff fluxes have provided evidence of ecosystem recovery from acidification. In this study, we combined for the first time mass budget data (sulfur deposition and total dissolved inorganic nitrogen (DIN) export) from the GEOMON monitoring network of headwater catchments with annual trajectories of vegetation indices derived from Landsat remote sensing observations. Time series of selected vegetation indices was constructed from Landsat 5, 7, and 8 using Google Earth Engine. Linear regression between the field data and vegetation indices was analyzed using R software. Biogeochemical responses of the forested catchment to declining acid deposition (driven by SO2 emission reduction) were consistent across all catchments covering various forest stands from different regions of the Czech Republic. Significant correlations were found with total sulfur depositions, suggesting that the forests are continuously and consistently prospering from reductions in acid deposition. Disturbance index (DI) was the only vegetation index that was well-related to changes in forest cover associated with salvage loggings (due to the forest decline) during the 1980s and 1990s. A significant relationship (R2 = 0.82) was found between the change in DI and DIN export in stream water. Regrowth of young forests in these highly affected areas tracks the most pronounced changes in total DIN export, suggesting a prominent role of vegetation in nitrogen retention. With the Landsat-derived DI, we could map decennial changes in forest disturbances beyond the small scale of the catchments to the regional level (demonstrated here for two protected landscape areas). This analysis showed the peak in forest disturbances to have occurred around the mid-1990s, followed by forest recovery and regrowth. Despite the improvement in forest ecosystem functioning over the past three decades in mountainous areas, emerging threats connected to changing climate will shape forest development in the near future. [ABSTRACT FROM AUTHOR]

• 44Ca/40Ca and 87Sr/86Sr ratios were studied at 3 sites with contrasting inputs from acidifying pollutants and bedrock. • A 19-year time-series of catchment input–output mass balances was also used to constrain Ca origin in runoff. • δ44Ca values of runoff were always higher than those of bedrock, with soil water having higher δ44Ca values than tree tissues. • δ44Ca values of runoff were close to those of rainfall, indicating export of atmospheric Ca from the catchments. • While soil systematically contains bedrock Ca, vegetation obtains a large part of its Ca from atmospheric and organic sources. [ABSTRACT FROM AUTHOR]