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Primary forest distribution and representation in a Central European landscape: Results of a large-scale field-based census
Abstract
Given the global intensification of forest management and climate change, protecting and studying forests that develop free of direct human intervention-also known as primary forests-are becoming increasingly important. Yet, most countries still lack data regarding primary forest distribution. Previous studies have tested remote sensing approaches as a promising tool for identifying primary forests. However, their precision is highly dependent on data quality and resolution, which vary considerably. This has led to underestimation of primary forest abundance and distribution in some regions, such as the temperate zone of Europe. Field-based inventories of primary forests and methodologies to conduct these assessments are inconsistent; incomplete or inaccurate mapping increases the vulnerability of primary forest systems to continued loss from clearing and land-use change. We developed a comprehensive methodological approach for identifying primary forests, and tested it within one of Europe's hotspots of primary forest abundance: the Carpathian Mountains. From 2009 to 2015, we conducted the first national-scale primary forest census covering the entire 49,036 km 2 area of the Slovak Republic. We analyzed primary forest distribution patterns and the representativeness of potential vegetation types within primary forest remnants. We further evaluated the conservation status and extent of primary forest loss. Remaining primary forests are small, fragmented, and often do not represent the potential natural vegetation. We identified 261 primary forest localities. However, they represent only 0.47% of the total forested area, which is 0.21% of the country's land area. The spatial pattern of primary forests was clustered. Primary forests have tended to escape anthropogenic disturbance on sites with higher elevations, steeper slopes, rugged terrain, and greater distances from roads and settlements. Primary forest stands of montane mixed and subalpine spruce forests are more abundant compared to broadleaved forests. Notably, several habitat types are completely missing within primary forests (e.g., floodplain forests). More than 30% of the remaining primary forests are not strictly protected, and harvesting occurred at 32 primary forest localities within the study period. Almost all logging of primary forests was conducted inside of protected areas, underscoring the critical status of primary forest distribution in this part of Europe. Effective conservation strategies are urgently needed to stop the rapid loss and fragmentation of the remaining primary forests. Our approach based on precise, field-based surveys is widely applicable and transferrable to other fragmented forest landscapes.
... At the highest altitudes, near the upper treeline (1,200-1,600 m a. s. l.), forests are naturally dominated by spruce (Mirek 2013;Čada et al. 2020). However, due to the long history of human settlement, most of the Central European forests have been subjected to more or less intensive use (Mikoláš et al. 2019). Therefore, only fragments of original forest remain in the most inaccessible and remote parts of the Western Carpathian mountains, which account for less than ~10,600 ha (0.5%) of Slovakian forests (Jasík and Polák 2011; Mikoláš et al. 2019). ...
... However, due to the long history of human settlement, most of the Central European forests have been subjected to more or less intensive use (Mikoláš et al. 2019). Therefore, only fragments of original forest remain in the most inaccessible and remote parts of the Western Carpathian mountains, which account for less than ~10,600 ha (0.5%) of Slovakian forests (Jasík and Polák 2011; Mikoláš et al. 2019). ...
... Our study was conducted in the Western Carpathian Mountains (Slovakia), between 48.632749° and 49.523229° N and between 19.010233° and 20.118049° E, elevation of our research plots was between 769 and 1,534 m. Research plots were located inside primary forest remnants recognised by the national inventory of primary forests in Slovakia (Jasík and Polák 2011; Mikoláš et al. 2019). During inventory, all potential primary forest areas were visually surveyed for structural elements, typical for primary forests. ...
Mountain spruce- and beech-dominated forests (SDPF and BDPF) are of major importance in temperate Europe. However, information on the differences between their historical disturbance regimes, structures, and biodiversity is still incomplete. To address this knowledge gap, we established 118 circular research plots across 18 primary forest stands. We analysed the disturbance history of the last 250 years by dendrochronological methods and calculated disturbance frequency, severity, and timing. We also measured forest structure (DBH, tree density, volume of deadwood, and other parameters). Breeding bird populations were examined by point count method during the spring seasons 2017–2018 (SDPF) and 2019–2020 (BDPF). Using direct ordination analysis, we compared the disturbance history, structure and bird assemblage in both forest types. While no differences were found regarding disturbance regimes between forest types, forest structure and bird assemblages were significantly different. SDPF had a significantly higher density of cavities and higher canopy openness, while higher tree species richness and more intense regeneration was found in BDPF. Bird assemblage showed higher species richness in BDPF, but lower total abundance. Most bird species which occurred in both forest types were more numerous in spruce-dominated forests, but more species occurred exclusively in BDPF. Further, some SDPF- preferring species were found in naturally disturbed patches in BDPF. We conclude that although natural disturbances are important drivers of primary forest structures, differences in the bird assemblages in the explored primary forest types were largely independent of disturbance regimes.
... Norway spruce disturbance dynamics Remaining forests are managed for erosion prevention, water retention and recreation (25.4%, Anonymous, 2019). Strictly protected unmanaged areas promoting nature conservation account for 2.5% of the forest area, of which 0.5% are unmanaged old-growth forests (Mikoláš et al., 2019). The prevalent management type is shelterwood management (72%), followed by clear-cutting (26%, Anonymous, 2019). ...
... While higher age and lower species diversity are likely to increase forest propensity to wind and bark beetles, these effects may have been overwhelmed by the thermal limitation constraining beetles' development and a smaller abundance of vulnerable spruce. Although lower species diversity in the strict reserves can be surprising, some of the investigated forests represent subalpine Norway spruce ecosystems formed by a limited number of species and with a monotonous age structure (Mikoláš et al., 2019). However, such forests can show a high ecological resilience to disturbances (Janda et al., 2017). ...
... planned and sanitary harvests). Although we included only strict reserves under a no-management regime, some harvests may have occurred in old-growth forests, although to a limited extend (Mikoláš et al., 2019), for example, in relation to sanitation removal of trees infested by bark beetles that are permitted under some circumstances. Another issue is a problematic differentiation of planned harvest and natural disturbance in production forests, where they concur. ...
Forest disturbances are intensifying globally, yet regional drivers of these dynamics remain poorly understood. We investigated recent disturbance intensities in Norway spruce (Picea abies L.) forests in Slovakia (Central Europe) with different management objectives in 2000-2017 based on Landsat imagery. We focused on 122 strict reserves without any management, their actively managed surroundings (500 m and 2000 m buffers), and managed production forests beyond the buffer areas. We used generalized additive mixed models to test for differences in temporal trends of disturbance intensity among these management categories. We found that disturbance intensity was increasing in all management categories during the studied period. The increase was more pronounced in the managed forests (compound annual disturbance rate 1.76% year −1) and the 2000 m buffer (2.21% year −1) than in the strict reserves (0.58% year −1). The predicted cumulative disturbance during the 18-year period was 9.9% in the reserves and 30.5% in the 2000 m buffer. We found that forests in nature reserves can be more resistant to disturbances than forests managed for timber production, despite management efforts to control disturbances in managed forests. Our findings can help reconcile the different perceptions of natural disturbances and their management in Central Europe and support climate-adapted management strategies that consider natural disturbances as an indispensable component of ecosystem dynamics.
... 13 Accessed on: 12-11-2020 14 https://www.iucn.org/theme/protected-areas/about/protected-area-categories wood removal in recent years in Europe Senf et al. 2018), even inside protected areas (Mikoláš et al. 2019). This suggests that the role of strictly protected areas should be monitored and enforced to be fully effective. ...
... The size of an individual stand in beech forests is often between 20 and 25 ha. There is a large variability, though, as it can be as small as 5-10 ha (Mikoláš et al. 2019;Peck et al. 2015) or may reach an extent of 50 ha (Vandekerkhove 2017). While these small sizes might be sufficient to allow the occurrence of small-scale gap dynamics and disturbances in beech forests, recent evidence suggests that fine-scale disturbance is not the only agent in these forests. ...
... A practical application of the minimum dynamic area concept is reported in Mikoláš et al. (2019), where they compare two alternative approaches to primary forest conservation in Slovakia (Figure 4). In the first case, a large reserve was established in the Ticha and Koprova valleys, where fragmented primary forests (363 ha) were connected into a 9,188 ha forest complex which was left for natural development. ...
... Many threatened wood-inhabiting fungi are dispersal-limited and depend on landscape-level connectivity to retain viable populations (Abrego et al. 2016). In Slovakia, oldgrowth forests and their remnants cover 0.47% of the total forested area, which is 0.21% of the country's land area (Jasík et al. 2017, Mikoláš et al. 2019. They are distributed unequally across the country, especially caused by landscape morphology and fragmented and threatened by human activity (Mikoláš et al. 2019). ...
... In Slovakia, oldgrowth forests and their remnants cover 0.47% of the total forested area, which is 0.21% of the country's land area (Jasík et al. 2017, Mikoláš et al. 2019. They are distributed unequally across the country, especially caused by landscape morphology and fragmented and threatened by human activity (Mikoláš et al. 2019). ...
... This was done after discussing with data contributors the criteria and categories used for constructing their datasets, which we then mapped onto our definition framework. Depending on the datasets, these criteria included: (1) forest age or structural variables 19,23,36 , (2) legal designation 25 or year since onset of protection 37 , (3) time since last anthropogenic disturbancee 38 , or (4) the lack of human impacts and infrastructures 39 . ...
... Since our data were collected continuously over the last two decades, we cannot exclude that some forest patches may have undergone human disturbance after data collection. This is particularly relevant for areas where primary forests are lost at high rates, such as the Carpathians, Russian Karelia, or Northern Fennoscandia [18][19][20] . To assess to what extent this might be an issue, we used the open-access Landsat archive and the LandTrendr disturbance detection algorithm 50,51 , using Google Earth Engine 52 (Fig. 5). ...
Primary forests, defined here as forests where the signs of human impacts, if any, are strongly blurred due to decades without forest management, are scarce in Europe and continue to disappear. Despite these losses, we know little about where these forests occur. Here, we present a comprehensive geodatabase and map of Europe’s known primary forests. Our geodatabase harmonizes 48 different, mostly field-based datasets of primary forests, and contains 18,411 individual patches (41.1 Mha) spread across 33 countries. When available, we provide information on each patch (name, location, naturalness, extent and dominant tree species) and the surrounding landscape (biogeographical regions, protection status, potential natural vegetation, current forest extent). Using Landsat satellite-image time series (1985–2018) we checked each patch for possible disturbance events since primary forests were identified, resulting in 94% of patches free of significant disturbances in the last 30 years. Although knowledge gaps remain, ours is the most comprehensive dataset on primary forests in Europe, and will be useful for ecological studies, and conservation planning to safeguard these unique forests.
... This study was conducted in primary temperate mountain forests of the Carpathian Mountains and the Balkan peninsula, spanning from beech-dominated and mixed forests (hereafter referred to as beech-dominated) at lower elevations to spruce-dominated forests at higher elevations. These two regions contain the largest remnants of primary forests in the temperate zone of Europe (Janda et al., 2019;Mikoláš et al., 2019;Nagel et al., 2014;Sabatini et al., 2018). ...
... Primary forests were characterized as unmanaged forests with natural stand composition, diverse horizontal, vertical, and age structure, and a significant amount and diversity of downed and standing dead trees in different stages of decomposition; most stands were typically in an old-growth stage of development, but early seral stages developing after more severe natural disturbances were also present in these primary-forest sites (Mikoláš et al., 2019). The data set used for this study is a part of the REMOTE network (for more details see www.remot efore sts.org), which is focused on surveying remaining tracts of primary-forest landscapes in Europe and long-term study of their dynamics. ...
Aims
We examined differences in lifespan among the dominant tree species (spruce (Picea abies (L.) H. Karst.), fir (Abies alba Mill.), beech (Fagus sylvatica L.), and maple (Acer pseudoplatanus L.)) across primary mountain forests of Europe. We ask how disturbance history, lifetime growth patterns, and environmental factors influence lifespan.
Locations
Balkan mountains, Carpathian mountains, Dinaric mountains.
Methods
Annual ring widths from 20,600 cores from primary forests were used to estimate tree life spans, growth trends, and disturbance history metrics. Mixed models were used to examine species-specific differences in lifespan (i.e. defined as species-specific 90th percentiles of age distributions), and how metrics of radial growth, disturbance parameters, and selected environmental factors influence lifespan.
Results
While only a few beech trees surpassed 500 years, individuals of all four species were older than 400 years. There were significant differences in lifespan among the four species (beech > fir > spruce > maple), indicating life history differentiation in lifespan. Trees were less likely to reach old age in areas affected by more severe disturbance events, whereas individuals that experienced periods of slow growth and multiple episodes of suppression and release were more likely to reach old age. Aside from a weak but significant negative effect of vegetation season temperature on fir and maple lifespan, no other environmental factors included in the analysis influenced lifespan.
Conclusions
Our results indicate species-specific biological differences in lifespan, which may play a role in facilitating tree species coexistence in mixed temperate forests. Finally, natural disturbances regimes were a key driver of lifespan, which could have implications for forest dynamics if regimes shift under global change.
... Only a small number of national-scale inventories have been completed and published (Sabatini et. al., 2018;Mikoláš et al., 2019b;Sabatini et al., 2020b, pre-print not certified by peer review). The Czech Republic is one example where a nationalscale forest naturalness assessment found 490 old-growth forests, together totaling an area of 30,000 ha (Adam and Vrska, 2009;Kraus and Krumm, 2013). ...
... For the purpose of mapping primary and old-growth forests, it may not be necessary to determine the exact age of the oldest trees. Experience from primary forest inventories shows that veteran trees -the largest living and/or dead trees on the site which already show signs of slow dying -can be relatively easily identified (Mikoláš et al., 2019b). ...
Primary and old-growth forests in the EU are extremely rare and threatened, yet play an irreplaceable role in biodiversity conservation and the provision of other ecosystem services such as carbon storage. Recognising this, the EU Biodiversity Strategy for 2030 sets the target to strictly protect all remaining primary and old-growth forests. This target is part of a wider goal to protect 30% of EU land and to dedicate 10% of EU land for strict protection. Strict protection of the remaining EU primary and old-growth forests is a first and crucial step to ensure their long-term conservation. Despite the importance of this target, its implementation is currently prevented by several unanswered questions that require discussion among science and policy experts. This includes, for example, the question of how old-growth forest should be defined and where remaining primary and old-growth forests are located. In addition, there are ongoing discussions of how to best support strict protection of primary and old-growth forests and how to maintain and restore biodiversity, for example by preserving and allowing old-growth attributes to develop in forests that are managed for purposes other than conservation. This study specifically focuses on old-growth forests, given the increasing debate around this type of forest in Europe and their importance for forest biodiversity, but also includes information that is relevant for primary forests in a wider sense. The objective of this study is to inform discussions surrounding the implementation of the EU Biodiversity Strategy for 2030 target to strictly protect primary and old-growth forests. The methods of this study included a review of scientific literature on (i) Defining old-growth forests, (ii) Evidence of old and old-growth forests in Europe; (iii) Approaches to protect old-growth forests and to maintain and develop old-growth attributes, (iv) Associated benefits, consequences, and potential trade-offs of old-growth forest protection and management and development of old-growth forest attributes; and (v) Policy implications.
... We assessed the historical disturbance of 20 beech-dominated primary mixed forests stands within the Carpathian Mountains of Slovakia and Romania. The presence of primary forests was determined through forest inventories in Slovakia (Kozák et al., 2018;Mikoláš et al., 2019;Sabatini et al., 2018; also see http:// remoteforests.org) and Romania (Kozák et al., 2018;Sabatini et al., 2018) and detailed descriptions of these primary forest inventories can be found in the study by Mikoláš et al., (2019). Primary forest stands occurred in four geographic clusters which we refer to as landscapes (West Slovakia, East Slovakia, North Romania, and South Romania) covering 42°-50° latitude and 14°-25° longitude, with plots ranging in elevation from 615 to 1,324 m a.s.l ( Figure 2a). ...
... We assessed the historical disturbance of 20 beech-dominated primary mixed forests stands within the Carpathian Mountains of Slovakia and Romania. The presence of primary forests was determined through forest inventories in Slovakia (Kozák et al., 2018;Mikoláš et al., 2019;Sabatini et al., 2018; also see http:// remoteforests.org) and Romania (Kozák et al., 2018;Sabatini et al., 2018) and detailed descriptions of these primary forest inventories can be found in the study by Mikoláš et al., (2019). Primary forest stands occurred in four geographic clusters which we refer to as landscapes (West Slovakia, East Slovakia, North Romania, and South Romania) covering 42°-50° latitude and 14°-25° longitude, with plots ranging in elevation from 615 to 1,324 m a.s.l ( Figure 2a). ...
Wind is the leading disturbance agent in European forests, and the magnitude of wind impacts on forest mortality has increased over recent decades. However, the atmospheric triggers behind severe winds in Western Europe (large‐scale cyclones) differ from those in Southeastern Europe (small‐scale convective instability). This geographic difference in wind drivers alters the spatial scale of resulting disturbances and potentially the sensitivity to climate change. Over the 20th century, the severity and prevalence of cyclone‐induced windstorms have increased while the prevalence of atmospheric instability has decreased and thus, the trajectory of Europe‐wide windthrow remains uncertain. To better predict forest sensitivity and trends of windthrow disturbance we used dendrochronological methods to reconstruct 140 years of disturbance history in beech‐dominated primary forests of Central and Eastern Europe. We compared generalized linear mixed models of these disturbance time series to determine whether large‐scale cyclones or small‐scale convective storms were more responsible for disturbance severity while also accounting for topography and stand character variables likely to influence windthrow susceptibility. More exposed forests, forests with a longer absence of disturbance, and forests lacking recent high severity disturbance showed increased sensitivity to both wind drivers. Large‐scale cyclone‐induced windstorms were the main driver of disturbance severity at both the plot and stand scale (0.1–∼100 ha) whereas convective instability effects were more localized (0.1 ha). Though the prevalence and severity of cyclone‐induced windstorms have increased over the 20 century, primary beech forests did not display an increase in the severity of windthrow observed over the same period.
... The data for this study were collected in primary forests of the Carpathian mountains and the Balkan peninsula ( Fig. 1), where the most extensive tracts of European primary temperate forests are found (Sabatini et al., 2018(Sabatini et al., , 2021Mikoláš et al., 2019). Primary forest sites were unmanaged with diverse horizontal, vertical, and age structures, containing significant amounts of standing and downed deadwood in different decomposition stages. ...
Canopy accession strategies reveal much about tree life histories and forest stand dynamics. However, the protracted nature of ascending to the canopy makes direct observation challenging. We use a reconstructive approach based on an extensive tree ring database to study the variability of canopy accession patterns of dominant tree species (Abies alba, Acer pseudoplatanus, Fagus sylvatica, Picea abies) in temperate mountain forests of Europe and elucidate how disturbance histories, climate, and topography affect canopy accession. All four species exhibited high variability of radial growth histories leading to canopy accession and indicated varying levels of shade tolerance. Individuals of all four species survived at least 100 years of initial suppression. Fir and particularly beech, however, survived longer periods of initial suppression, exhibited more release events, and reached the canopy later on average, with a larger share of trees accessing the canopy after initially suppressed growth. These results indicate the superior shade tolerance of beech and fir compared to spruce and maple. The two less shade-tolerant species conversely relied on faster growth rates, revealing their competitive advantage in non-suppressed conditions. Additionally, spruce from higher-elevation spruce-dominated forests survived shorter periods of initial shading and exhibited fewer releases, with a larger share of trees reaching the canopy after open canopy recruitment (i.e. in absence of suppression) and no subsequent releases compared to spruce growing in lower-elevation mixed forests. Finally, disturbance factors were identified as the primary driver of canopy accession, whereby disturbances accelerate canopy accession and consequently regulate competitive interactions. Intensifying disturbance regimes could thus promote shifts in species composition, particularly in favour of faster-growing, more light-demanding species.
... In particular, primary and old-growth forests with low human impact form important local biodiversity hotspots [5][6][7][8] . Hence, there is a growing need for effective mapping of such areas to safeguard their existence through conservation and restoration, and as a foundation for nature restoration and spatial planning to ensure habitat network functionality [9][10][11][12][13] . ...
To conserve biodiversity, it is imperative to maintain and restore sufficient amounts of functional habitat networks. Hence, locating remaining forests with natural structures and processes over landscapes and large regions is a key task. We integrated machine learning (Random Forest) and open landscape data to scan all forest landscapes in Sweden with a 1 ha spatial resolution with respect to the relative likelihood of hosting High Conservation Value Forests (HCVF). Using independent spatial stand-and plot-level validation data we confirmed that our predictions (ROC AUC in the range of 0.89-0.90) correctly represent forests with different levels of naturalness, from deteriorated to those with high and associated biodiversity conservation values. Given ambitious national and international conservation objectives, and increasingly intensive forestry, our model and the resulting wall-to-wall mapping fills an urgent gap for assessing fulfilment of evidence-based conservation targets, spatial planning, and designing forest landscape restoration.
... The main reason offered for the above-described destruction of primary forests is a policy that permits salvage logging of areas recently affected by natural disturbances (Spînu et al. 2020, Mikoláš et al. 2019). However, our results demonstrate that natural disturbances, synchronised across variable spatial scales and multiple forest types, are an indispensable part of the primary forest ecosystem. ...
Understanding temporal and spatial variations in historical disturbance regimes across intact, continuous, and altitudinally diverse primary forest landscapes is imperative to help forecast forest development and adapt forest management in an era of rapid environmental change. Because few complex primary forest landscapes remain in Europe, previous research has largely described disturbance regimes for individual forest types and smaller isolated stands. We studied the largest but still largely unprotected mountain primary forest landscape in temperate Europe, the Fagaraș Mountains of Romania. To describe historical disturbance regimes and synchronicity in disturbance activity and trends between two widespread forest community types, dominated by Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.), we established 191 permanent study plots (70 beech; 121 spruce) across 11 valleys, thereby providing information at both stand and landscape
levels. We used a dendrochronological approach to reconstruct and describe the spatiotemporal patterns of
historical disturbances. We observed a diverse spectrum of disturbance severities and timing across the forest landscape. High-severity disturbances created periods of synchrony in disturbance activity at the landscape scale, while moderate- and low-severity disturbances were asynchronous and random in both spruce- and beech-dominated primary forests. We detected a peak of canopy disturbance across the region at the end of the
nineteenth century, with the most important periods of disturbance between the 1890s and 1910s. At the stand scale, we observed periods of synchronised disturbances with varying severities across both forest types. The level of disturbance synchrony varied widely among the stands. The beta regression showed that spruce forests had significantly higher average synchrony and higher between-stand variability of synchrony than the beech-dominated forests. Synchronised disturbances with higher severity were infrequent, but they were critical as drivers of subsequent forest development pathways and dynamics across both forest types.
Our results provide valuable insight into future resilience to climate-driven alterations of disturbance regimes in spruce- and beech-dominated mountain temperate forests in the Carpathians. We suggest that conservation efforts should recognize strictly protecting large continuous and altitudinally diversified forest landscapes such as Fagaraș Mts. as a necessary measure to tackle climate change and ensure temporal and spatial structural heterogeneity driven by a wide range of disturbances. The diverse and synchronous disturbance activity among two interconnected forest vegetation types highlights the need for complex spatiotemporal forest management approaches that emulate disturbance synchronicity to foster biodiversity across multiple forest vegetation types within forest landscapes.
... The original aim of the inventory was to decide for each stand if it fulfilled the criteria fora primary forest (e.g. absence of stumps; Mikoláš et al., 2019). All study plots are included in primary forest dataset of the REMOTE project (Remote Primary Forest, 2019). ...
1. Natural disturbances change forest habitat quality for many species. As the extent and intensity of natural disturbances may increase under climate change, it is unclear how this increase can affect habitat quality on different spatial scales. To support management tools and policies aiming to prevent habitat loss, we studied how habitat quality develops in the long run depending on the disturbance severity using a space-for-time substitution approach.
2. We explored the effects of time since disturbance (0–250 years) and disturbance severity (20%–100% canopy removal) on structure-based habitat quality indicators in European primary Norway spruce Picea abies forests using 1000 m2 circular plots in hierarchical design (a total of 407 plots in 35 stands). Disturbance history was reconstructed from tree cores. Habitat quality indicators were modelled as a function of the severity of the most severe disturbance and the time since this disturbance. We hypothesised that high within-stand habitat heterogeneity is formed by different successional stages after disturbances of various intensities.
3. The results showed a U-shaped response of habitat quality to post-disturbance habitat succession on the plot scale. The decline deepened with disturbance severity. The U- shape response occurred in: large tree occurrence, amount of standing and lying deadwood, diversity of understory and understory openness. The spatial diversity in disturbance parameters increased spatial diversity of habitat quality on a stand level as expected. This high within-stand habitat heterogeneity also decreased with increasing age of the most recent disturbance. This suggests that the absence of young successional stages results in the absence of some important elements for biodiversity, for example sun-exposed snags.
4. Synthesis and applications. Our results demonstrate that currently intensifying natural disturbance regime can consequently result in a lower habitat heterogeneity. In managed spruce forests after natural disturbances, we recommend at
This least the partial retention of biological legacies to preserve habitat heterogeneity and to avoid uniform and dense plantations resulting in a greater homogenisation. To emulate the natural disturbances pattern, spruce forests should be managed with a wide range of harvested patches of the size limited by a local natural disturbance regime creating spatial heterogeneity.
... Old-growth forests are known to harbour high biodiversity and are especially important for the occurrence of rare and endangered species confirming their importance for conservation goals (Tikkanen et al., 2006;Moning & Müller, 2009;Dittrich et al., 2014). Nevertheless, the area of old-growth and primary forests continues to decline and many stands highly valuable for biodiversity preservation still have insufficient protection (Mikoláš et al., 2019;Sabatini et al., 2018Sabatini et al., , 2020. The large-scale disturbances in Central European Norway spruce (Picea abies Karst.) ...
An ongoing loss of Europe’s old-growth forests urgently calls for improving our understanding of native biodiversity response to habitat changes. Studies disentangling the effects of habitat quantity, quality, and continuity on species diversity are rare, however, understanding the differences between these effects is crucial for forest management and conservation efforts. Here, we investigated the influence of habitat quantity, quality, and continuity on the total and red-listed species richness of wood-inhabiting fungi in old-growth mountain Norway spruce (Picea abies Karst.) forest in Central Europe. The fruitbody-based mycological survey conducted on permanent plots was combined with the measurements of forest structural characteristics such as deadwood volumes (indicating habitat quantity), dimensions, and decay stages (indicating habitat quality). Additionally, precise dendrochronological measurements were used to estimate the mean age of five oldest trees and the number of >250 years-old-trees (i.e., those that survived a probable logging activity about 250 years ago) as indicators of habitat continuity. Our results showed the total species richness of wood-inhabiting fungi to be best correlated with habitat quantity (volume of low snags and lying deadwood), while the red-listed species richness was best explained by habitat continuity indicated by the number of >250 years-old-trees. Our study provides novel evidence regarding uninterrupted habitat continuity being crucial in supporting red-listed fungal species. Stands with preserved habitat continuity (e.g., the absence of clearcutting and deforestation) as well as old-growth stands with long habitat history should be prioritised for conservation. Greater degree of retention forestry practices should be required in production forests to preserve habitat continuity. Our study shows that such decisions are likely to lead to positive effects that can persist for centuries.
... By primary forest, we mean a forest without signs of direct human impact and where natural disturbances are the main driver of forest structure and composition (Barredo et al., 2021). The study forests were selected based on previous inventories of primary forest remnants when available (e.g., Mikoláš et al., 2019;Veen et al., 2010) and by searching the available archival information and historical data regarding the land-use history of these areas. During the initial field survey, all forests were inspected for various indicators of naturalness (e.g., deadwood in various stages of decay, pitand-mound topography, very large trees, and natural tree species composition) and for signs of human impact. ...
Protecting structural features, such as tree-related microhabitats (TreMs), is a cost-effective tool crucial for biodiversity conservation applicable to large forested landscapes. While the development of TreMs is influenced by tree diameter, species, and vitality, the relationships between tree age and TreM profile remain poorly understood. Using a tree-ring based approach and a large data set of 8038 trees, we modeled the effects of tree age, diameter, and site characteristics on TreM richness and occurrence across some of the most intact primary temperate forests in Europe, including mixed beech and spruce forests. We observed an overall increase in TreM richness on old and large trees in both forest types. The Occurrence of specific TreM groups was variably related to tree age and diameter, but some TreM groups (e.g., epiphytes) had a stronger positive relationship with tree species and elevation. While many TreM groups were positively associated with tree age and diameter, only 2 TreM groups in spruce stands reacted exclusively to tree age (insect galleries and exposed sapwood) without responding to diameter. Thus, the retention of trees for conservation purposes based on tree diameter appears to be a generally feasible approach with rather low risk of underrepresentation of TreMs. Because greater tree age and diameter positively affected TreM development, placing a greater emphasis on conserving large trees and allowing them to reach older ages, for example, through establishment of conservation reserves, would better maintain the continuity of TreM resource and associated biodiversity. However, this approach may be difficult due to the widespread intensification of forest management and global climate change. Article Impact Statement: Conservation of habitat trees based on size, without considering tree age, may impair landscape-level biodiversity potential. This article is protected by copyright. All rights reserved.
... The study area includes a zone of supramontane Norway spruce forests of the Western Carpathians (Slovakia, Central Europe, Fig. 1). A network of permanent plots was established within 11 localities and five mountain ranges using random sampling in the core zones of primary forest areas (as evaluated by a previous national-level field census; Mikoláš et al. 2019). A 141.4 × 141.4 m grid (cell size 2 ha) was overlaid on the area; within each grid cell, a circular sample plot was established at a restricted random position (the inner 0.49 ha core in each cell) using GPS (see Svoboda et al. 2014;Janda et al. 2017 for details). ...
... Therefore, GIS is a powerful tool in spatial decision-making processes for sustainable development in rural areas [23]. In addition, GIS is an effective software for census land uses in both field-scale and remote-sensing approaches [24,25], which could help to reduce the poor accuracy and limited updating of cadastral data concerning land use [26]. ...
The identification of mountainous areas suitable for chestnut stands for fruit production (CSFP) is raising increasing interest among researchers. This work aimed to (i) identify the areas suitable for CSFP shown in a land suitability map easy to read by land planners, and (ii) propose a remote-sensing-based methodology able to identify the lands currently under cultivation for CSFP. This study was conducted using the QGIS software for the Municipality of Castel del Rio, Emilia-Romagna Region, Italy. To obtain the land suitability map, topographic, lithological, and pedological data were acquired, and the areas located between 200 and 1000 m of altitude, with north exposition, a slope <20°, sandstone-based lithology, and soils with dystric features were selected. The currently cultivated areas for CSFP were identified through remote-sensing images of the early spring period, which were delineated and georeferenced. The findings showed that only 10% of the whole study site area can be considered suitable for CSFP. Further, most of the currently cultivated CSFP (59%) are in non-suitable areas characterised by high slope gradients. The methodology applied in this study can easily provide detailed information about the suitable areas for CSFP and the areas currently cultivated with chestnut, thus allowing accurate land-use planning and land conservation.
... E) (Fig. 1). A unique feature of this network is its focus on unmanaged, primary forests (Mikoláš et al., 2019). The database contains tree-ring records from more than 35,000 trees originating from more than 2,000 plots. ...
Global change outcomes for forests will be strongly influenced by the demography of juvenile trees. We used data from an extensive network of forest inventory plots in Europe to quantify relationships between climate factors and growth rates in sapling trees for two ecologically dominant species, Norway spruce and European beech. We fitted nonlinear regression models with annual radial growth measurements from ~17,500 trees in primary forests to investigate the sensitivity of individuals to temperature and measures of water supply. We controlled for multiple, potentially confounding factors, including ontogeny, resource competition and the deposition of anthropogenic nitrogen and sulphur. The growth potential of spruce was markedly elevated relative to beech, reflecting species-specific relationships with environmental drivers. Declining water availability more strongly limited productivity in spruce, while beech was notably tolerant of observed levels of moisture limitation. Warming promoted growth in both species, but growing season temperatures that exceeded thermally optimum conditions constrained wood production. We identified long-term positive trends in reconstructed annual rates of juvenile tree growth since the early 19 th century, likely driven by industrial-era warming. However, our findings suggest that sustained warming and more prevalent future drought may ultimately inhibit growth due to thermal thresholds and a differential tolerance of water stress. Consequently, global change factors may be expected to affect future species abundance patterns, biomass production, and the carbon sink capacity of forests in Europe.
... The disintegration stage is the early successional stage of the newly forming beech stand. In this study, areas of early disturbance were confirmed to be sites of high beetle richness 4,39,80 . However, this phase lasts for a relatively short time, typically up to 20 years 47 , after which species richness declines rapidly, according to our observations. ...
Natural dynamics in forests play an important role in the lives of many species. In the landscape of managed forests, natural disturbances are reduced by management activities. This usually has a significant effect on insect diversity. The effect of small-scale natural dynamics of protected beech stands on the richness of saproxylic and non-saproxylic beetles was investigated. Sampling was carried out by using flight interception traps in the framework of comparing different developmental stages: optimum, disintegration, and growing up, each utilizing 10 samples. We recorded 290 species in total, of which 61% were saproxylic. The results showed that the highest species richness and thus abundance was in the disintegration stage. In each developmental stage, species variation was explained differently depending on the variable. Deadwood, microhabitats, and canopy openness were the main attributes in the later stages of development for saproxylic beetles. For non-saproxylics, variability was mostly explained by plant cover and canopy openness. Small-scale disturbances, undiminished by management activities, are an important element for biodiversity. They create more structurally diverse stands with a high supply of feeding and living habitats. In forestry practice, these conclusions can be imitated to the creation of small-scale silvicultural systems with active creation or retention of high stumps or lying logs.
... The study area includes a zone of supramontane Norway spruce forests of the Western Carpathians (Slovakia, Central Europe, Fig. 1). A network of permanent plots was established within 11 localities and five mountain ranges using random sampling in the core zones of primary forest areas (as evaluated by a previous national-level field census; Mikoláš et al. 2019). A 141.4 × 141.4 m grid (cell size 2 ha) was overlaid on the area; within each grid cell, a circular sample plot was established at a restricted random position (the inner 0.49 ha core in each cell) using GPS (see Svoboda et al. 2014;Janda et al. 2017 for details). ...
Development of primary spruce forests is driven by a series of disturbances, which also have an important influence on the understorey vegetation and its diversity. Early post-disturbance processes have been intensively studied, however, very little is known about the long-term effects of disturbances on the understorey. We quantified disturbance history using dendrochronological methods to investigate its impact on vascular plant diversity and understorey species composition. We sampled 141 plots randomly assigned throughout primary stands located in the zone of natural montane acidophilous forests dominated by Picea abies (L.) Karst. in the Western Carpathians. Dendrochronological, dendrometric, and environmental parameters were related to understorey properties using ordination methods and a Bayesian approach using multilevel linear models (GLMM).
Time since the last disturbance (23–260 years ago; mostly windstorms and bark beetle outbreaks) had a significant effect on understorey species composition of the current communities, and it also interacted with disturbance severity to influence species diversity. The effect of disturbances on the understorey was largely mediated by the alteration of stand structure (age, DBH, canopy openness), Vaccinium myrtillus L. cover, and topsoil chemical properties. A period of severe disturbances between 1860 and 1890 resulted in a legacy of our current, relatively homogeneous spruce stands with less diverse sciophilous understorey dominated by V. myrtillus, which is in contrast to heterogeneous stands (in terms of age and spatial structure) driven by small-scale, lower-severity disturbances, which led to an understorey enriched by species with higher demands on light and topsoil quality (higher K concentration and lower C/N ratio).
All developmental pathways following disturbances create a unique complex of spatiotemporal understorey variability in the montane spruce forests. Therefore, to preserve their full diversity, disturbances of all severities and sizes should be accepted as natural drivers, both in the field of nature conservation and close-to-nature forestry efforts.
... The main reason offered for the above-described destruction of primary forests is a policy that permits salvage logging of areas recently affected by natural disturbances (Spînu et al. 2020, Mikoláš et al. 2019). However, our results demonstrate that natural disturbances, synchronised across variable spatial scales and multiple forest types, are an indispensable part of the primary forest ecosystem. ...
... Primary forests can be especially valuable biodiversity refugia in any landscape condition we conclude. The current concern with its continuous loss [106][107][108][109] is justified. However, detailed studies in land-use history are necessary to detect whether an old-growth forest in landscapes influenced by humans long ago is truly primary (as re-vealed for the PrFS in the Visim NBR). ...
One of the essential tasks of sustainable forest management is to maintain native biodiversity. Primary forest research is one of the ways to understand what this biodiversity is. Matherials and methods. The primary, as confirmed by their land-use history and structural peculiarities, mesic dark-conifer forests remain in Visim and Pechora–Ilych nature biosphere reserves (boreal and sub-boreal zones respectively, the Ural Mountains, Russian Federation). We compared the primary forests and post fire 100-year small-leaved deciduous forests by diversity of vascular flora and soil invertebrate macrofauna. Results and discussion. The diversity of some functional groups of species (low boreal herbs, earthworms) in post fire forests is lower than in primary forests, the research shows. These species largely depend on deadwood and other tree-related microhabitats common in the primary forests but not so in the 100-year post fire forests. Repeated fires at intervals of several decades, as is the case with the use of prescribed fires in forest management, will be expected to reduce the biodiversity quality of these specialist species. Additionally, we revealed that post fire forest flora is more synanthropic in the woodland of a small area (Visim reserve) than in the intact forest landscape (Pechora–Ilych reserve). It demonstrates that, within extensive woodlands, native forests are more resilient to sporadic stand-replacing disturbances than small woodlands. Conclusion. Strict conservation of intact forest landscapes is necessary as they serve as large buffer areas around the remaining primary forests to maintain native biodiversity.
... Forest naturalness of Czech localities was taken from the Czech Natural Forests website (www.naturalforests.cz) and for the Slovak ones from an unpublished map related to the work by Jasík et al. (2017) and Mikoláš et al. (2019). ...
Open access version available at Czech Mycology web page: http://www.czechmycology.org/_cmo/CM74106.pdf. Abstract: Records of Cyphella digitalis from the Czech Republic and Slovakia are summarised and discussed. ITS barcode of two collections was obtained to document their conspecificity with the only
so far sequenced sample originating from the Alps. In the study area, C. digitalis is rare with ten localities known from the 20th century and nine recorded in the 21st century. They are situated in the Bohemian Forest and several mountain ranges of the Western and Eastern Carpathians. The elevation range of the records is 525–1200 m a.s.l. All records are from Abies alba, mostly branches attached to freshly fallen trunks and sticking out into the air. Basidiomata occur in Fagus-Abies or Fagus-AbiesPicea forests from September to March with a peak in September–November. Most stands represent
old-growth forests under protection. Ecology and distribution are discussed in a broad European context. The much lower number of records in the Czech Republic and Slovakia compared to more western countries could have, among other things, also biogeographical reasons, i.e. decrease in occurrence with increasing continentality to the east
... Moreover, the distribution, composition, and dynamics of European forest landscapes have been fundamentally altered by millennia of human influence Kaplan et al., 2009;Keeton et al., 2013;Pretzsch et al., 2017). Consequently, finding reference forests in which to observe baseline disturbance dynamics is needed, but also highly challenging, because only small fragments of primary or old-growth forests remain in most places (Mikol aš et al., 2019;Szwagrzyk & Gazda, 2007). The proportion of remnant old-growth (primary) forests is only 0.7% of the forest cover in Europe (without Russia), with montane beech forests overrepresented relative to other forest types (Sabatini et al., 2018). ...
In Europe, forest management has controlled forest dynamics to sustain commodity production over multiple centuries. Yet over‐regulation for growth and yield diminishes resilience to environmental stress as well as threatens biodiversity, leading to increasing forest susceptibility to an array of disturbances. These trends have stimulated interest in alternative management systems, including natural dynamics silviculture (NDS). NDS aims to emulate natural disturbance dynamics at stand and landscape scales through silvicultural manipulations of forest structure and landscape patterns. We adapted a “Comparability Index” (CI) to assess convergence/divergence between natural disturbances and forest management effects. We extended the original CI concept based on disturbance size and frequency by adding the residual structure of canopy trees after a disturbance as a third dimension. We populated the model by compiling data on natural disturbance dynamics and management from 13 countries in Europe, covering four major forest types (i.e., spruce, beech, oak, and pine‐dominated forests). We found that natural disturbances are highly variable in size, frequency, and residual structure, but European forest management fails to encompass this complexity. Silviculture in Europe is skewed towards even‐aged systems, used predominately (72.9% of management) across the countries assessed. The residual structure proved crucial in the comparison of natural disturbances and silvicultural systems. CI indicated the highest congruence between uneven‐aged silvicultural systems and key natural disturbance attributes. Even so, uneven‐aged practices emulated only a portion of the complexity associated with natural disturbance effects. The remaining silvicultural systems perform poorly in terms of retention as compared to tree survivorship after natural disturbances. We suggest that NDS can enrich Europe's portfolio of management systems, for example where wood production is not the primary objective. NDS is especially relevant to forests managed for habitat quality, risk reduction, and a variety of ecosystem services. We suggest a holistic approach integrating natural dynamics silviculture with more conventional practices.
... Expanding frontiers of clear-cut forestry (e.g. Seedre et al. 2018; into such areas is a main cause of forest and biodiversity loss worldwide Venier et al. 2018;Mikoláš et al. 2019;Betts et al. 2021). More ambitious conservation Communicated by José Valentin Roces-Diaz. ...
Intact forest landscapes harbor significant biodiversity values and pools of ecosystem services essential for conservation, land use and rural development. Threatened by fragmentation and loss by transitions to industrial clear-cut forestry, those landscapes are of pivotal interest for protection that secures their intact character. With wall-to-wall land-cover data, we explored opportunities for maintaining intact forest landscapes through comprehensive spatial planning across a 2.5 million hectares boreal to sub-alpine forest region along the eastern slopes of the Scandinavian Mountain range. We analyzed forest and woodland types that are protected, need protection or potentially can be subject to continued forest management. We established that the fraction of already clear-cut forest is very small and that the forest landscape of the Scandinavian Mountain foothills contains a high proportion of protected high conservation value forests, covering almost 2 million ha, and that over 500,000 ha (27%) remains unprotected and may be subject to future protection or continued adapted forest management. We found evident north to south differences with respect to forest landscape configuration, distribution of unprotected forests and land ownership. With a focus on non-industrial private landowners, we conclude that sustainable land-use requires integrative, multi-functional approaches that rely on further protection, forest and forest landscape restoration and a much larger share of continuous cover forestry than presently. Our results provide input into ongoing policy implementation and green infrastructure planning in the context of securing intact forest values and integrative opportunities for rural livelihood and regional development based on multiple value chains.
... To fill this gap, in this research we analyse the spatial heterogeneity of canopy openness in multiaged old-growth forests formed by European beech, silver fir and Norway spruce . To capture the possible wide range of variation in structural attributes and the disturbance regime driving this forest ecosystem, we sampled old-growth stands growing in the Western Carpathians (Central Europe) and Dinaric Mountains (Southeastern Europe) which are believed to retain the structural attributes and dynamics of primeval forests (Mikoláš et al., 2019;Sabatini et al., 2018). At the between-stand level, we assume that average canopy openness is associated with the number and basal area of trees forming the overstory and that denser stands have lower canopy openness. ...
The action of many agents causing the mortality of overstory trees may potentially induce the formation of an aggregated distribution of canopy gaps. In this study we tested the hypothesis that natural stand dynamics generates an aggregated pattern of canopy openness in old-growth forests formed by Fagus sylvatica L., Abies alba Mill. and Picea abies (L.) H. Karst. We compared canopy openness and its spatial heterogeneity in five stands in the Western Carpathians (Central Europe) and three stands in the Dinaric Mountains (Southeast Europe). The stands were between 4.48 and 9.24 ha in size. In each stand we took hemispheric photographs in a regular 20 × 20 m grid in the leafless period to minimize coverage by the understory. Tree species and the dbh of live trees of dbh ≥7 cm were recorded on circular plots with a radius of 7 m centered at the grid points. At the stage of picture processing, understory trees of dbh <25 cm and polar coordinates recorded during field measurements were removed from the pictures, and for every grid point the local canopy openness of the overstory layer was determined in the sky region defined by a zenith angle of 15°. We characterized the spatial pattern of canopy openness by using variograms and Moran’s I coefficients and tested the spatial dependence in the distribution patterns of grid points characterized by different levels of canopy openness. Depending on the stand, mean canopy openness varied between 17.5 and 41.0%, with the greatest values recorded in the Carpathian stands with a considerable proportion of Norway spruce and a more severe disturbance regime. Relationships between canopy openness and the overall number, basal area or volume of trees forming the overstory were strongly modified by variation in the density and species percentage in the mid-canopy zone. In all the stands small-scale variation determined for inter-point distances of 20 m accounted for the majority of the total variation in canopy heterogeneity and ranged between 61 and 100%. We found a tendency to form random patterns of canopy openness in the Dinaric stands, which were characterized by a greater basal area and probably also lower frequency of severe disturbances, and aggregated patterns in the Carpathian stands, which were characterized by a smaller basal area driven by more severe disturbances. The revealed spatial dependence in canopy openness may suggest that in the studied ecosystem canopy gaps are not only a legacy of the mortality of canopy trees but also self-organizing structural elements which, under a more severe disturbance regime, can affect the mortality rate in their neighbourhood. Nonetheless, the percentage of spatially structured variability in canopy openness observable at scales larger than the grid spacing used in our study was insignificant (83% on average). The close-to-random pattern of canopy heterogeneity may weaken the spatio-temporal synchronization of the juvenile growth, maturation and senescence of neighbouring trees and counteract the formation of coarse-grained patch mosaics.
... Boubin forest is a typical representative of mixed mountain old-growth forest, serving as an "etalon" in the formation of traditional concepts of close-to-nature forest management [104,105]. Thus, our results might be extrapolated to analogical natural forests across the Europe, e.g., Novohradske Mts. in Central Europe [16], the Carphatians [18,19,106], the Alps [11,107], the Balkan peninsula [22,108] and Apennines [109]. This study determined several mutually overlapping factors that might contribute to wholestand resistance to severe storms. ...
The driving forces of tree mortality following wind disturbances of mountain mixed European temperate forests belongs among issues not comprehensively resolved. Hence, we aimed to elucidate the key factors of tree resistance to historical severe disturbance events in the Boubínský Primeval Forest, one of the oldest forest reserves in the Czech Republic. By using spatially explicit tree census, dendrochronological and soil data, we study spatial and temporal patterns of past disturbances and mathematically compared selected characteristics of neighboring trees that were killed by a severe storm in 2017 and those that remained undisturbed. The tendency of trees toward falling was primarily driven edaphically, limiting severe events non-randomly to previously disturbed sites occupied by hydromorphic soils and promoting the existence of two spatially-separated disturbance regimes. While disturbed trees usually recruited in gaps and experienced only one severe release event, surviving trees characteristically regenerated under the canopy and were repeatedly released. Despite the fact that disturbed trees tended to reach both lower ages and dimensions than survivors, they experienced significantly higher growth rates. Our study indicates that slow growth with several suppression periods emerged as the most effective tree strategy for withstanding severe windstorms, dying of senescence in overaged life stage. Despite the selective impact of the Herwart storm on conifer population, we did not find any difference in species sensitivity for most characteristics studied. We conclude that the presence of such ancient, high-density wood trees contributes significantly to the resistance of an entire stand to severe storms.
... Thirty primary forest stands with no signs of human management were selected in the subalpine zone of the Carpathian Mountains. Stands with no evidence of direct human influence, such as logging or livestock grazing, were selected with the help of local experts or primary forest inventories [31]. The studied forests occupy altitudes ranging from 1150 to 1700 m.a.s.l. ...
With accelerating environmental change, understanding forest disturbance impacts on trade-offs between biodiversity and carbon dynamics is of high socioeconomic importance. Most studies, however, have assessed immediate or short-term effects of disturbance, while long-term impacts remain poorly understood. Using a tree-ring-based approach, we analysed the effect of 250 years of disturbances on present-day biodiversity indicators and carbon dynamics in primary forests. Disturbance legacies spanning centuries shaped contemporary forest co-benefits and trade-offs, with contrasting, local-scale effects. Disturbances enhanced carbon sequestration, reaching maximum rates within a comparatively narrow post-disturbance window (up to 50 years). Concurrently, disturbance diminished aboveground carbon storage, which gradually returned to peak levels over centuries. Temporal patterns in biodiversity potential were bimodal; the first maximum coincided with the short-term post-disturbance carbon sequestration peak, and the second occurred during periods of maximum carbon storage in complex old-growth forest. Despite fluctuating local-scale trade-offs, forest biodiversity and carbon storage remained stable across the broader study region, and our data support a positive relationship between carbon stocks and biodiversity potential. These findings underscore the interdependencies of forest processes, and highlight the necessity of large-scale conservation programmes to effectively promote both biodiversity and long-term carbon storage, particularly given the accelerating global biodiversity and climate crises.
... We selected 10 primary spruce forest stands from an existing inventory of the primary forests of Slovakia (Mikoláš et al., 2019;REMOTE project: www.remot efore sts.org/proje ct.php). The stands ranged in size from 100 to 300 ha and were selected from a landscape of approximately 4,800 km 2 across five mountain ranges in the Western Carpathians ( Figure 1). ...
Aim
Natural disturbances influence forest structure, successional dynamics, and, consequently, the distribution of species through time and space. We quantified the long-term impacts of natural disturbances on lichen species richness and composition in primary mountain forests, with a particular focus on the occurrence of endangered species.
Location
Ten primary mountain spruce forest stands across five mountain chains of the Western Carpathians, a European hotspot of biodiversity.
Methods
Living trees, snags, and downed logs were surveyed for epiphytic and epixylic lichens in 57 plots. Using reconstructed disturbance history, we tested how lichen species richness and composition was affected by the current forest structure and disturbance regimes in the past 250 years. We also examined differences in community composition among discrete microhabitats.
Results
Dead standing trees as biological legacies of natural disturbances promoted lichen species richness and occurrence of threatened species at the plot scale, suggesting improved growing conditions for rare and common lichens during the early stages of recovery post-disturbance. However, high-severity disturbances compromised plot scale species richness. Both species richness and the number of old-growth specialists increased with time since disturbance (i.e. long-term uninterrupted succession). No lichen species was strictly dependent on live trees as a habitat, but numerous species showed specificity to logs, standing objects, or admixture of tree species.
Main conclusions
Lichen species richness was lower in regenerating, young, and uniform plots compared to overmature and recently disturbed areas. Natural forest dynamics and its legacies are critical to the diversity and species composition of lichens. Spatiotemporal consequences of natural dynamics require a sufficient area of protected forests for provisioning continual habitat variability at the landscape scale. Ongoing climatic changes may further accentuate this necessity. Hence, we highlighted the need to protect the last remaining primary forests to ensure the survival of regionally unique species pools of lichens.
... High-conservation-value forests (HCVFs) have a history of forest continuity and are typically composed of late-successional stands with structurally complex canopy and low levels of anthropogenic disturbance (Munteanu et al., 2015;Watson et al., 2018;Wirth et al., 2009). These forests provide valuable ecosystem services, such as carbon sequestration, and harbor high levels of biodiversity, including many endangered lichens, insects, and birds (Eckelt et al., 2018;Malíček et al., 2019;Mikoláš et al., 2019). Yet, increasing anthropogenic pressure accelerates the rate of HCVF loss (Curtis et al., 2018) and changes forest ecosystem dynamics (McDowell et al., 2020). ...
High conservation value forests (HCVF) are critically important for biodiversity and ecosystem service provisioning, but face manifold threats. Where systematic HCVF inventories are missing, such as in parts of Eastern Europe, these forests remain largely unacknowledged and therefore often unprotected. Here, we propose a novel, transferable approach for detecting HCVF, based on integrating historical spy satellite images, contemporary remote sensing data and information on current anthropogenic pressures. Using Romania as a pilot‐study, we mapped forest continuity (1955‐2019), canopy structural complexity, and anthropogenic pressures, and identified a large area (738,000 ha) of HCVF. More than half of this area is susceptible to current anthropogenic pressures and lacks formal protection. By providing a framework for broad‐scale HCVF monitoring, our approach facilitates integration of HCVF into forest conservation and management. This is urgently needed to achieve the goals of the European Union's Biodiversity Strategy to maintain valuable forest ecosystems. This article is protected by copyright. All rights reserved
... European old-growth forests are estimated to occupy only 0.7% of the total forested area . These fragmented forest patches are mainly confined to remote mountain areas with low levels of human pressure (Mikoláš et al., 2019). ...
Old-growth mountain forests represent an ideal setting for studying long-term impacts of climate change. We studied the few remnants of old-growth forests located within the Pollino massif (southern Italy) to evaluate how the growth of conspecific young and old trees responded to climate change. We investigated two conifer species (Abies alba and Pinus leucodermis) and two hardwood species (Fagus sylvatica and Quercus cerris). We sampled one stand per species along an altitudinal gradient, ranging from a drought-limited low-elevation hardwood forest to a cold-limited subalpine pine forest. We used a dendrochronological approach to characterize the long-term growth dynamics of old (age > 120 years) versus young (age < 120 years) trees. Younger trees grew faster than their older conspecifics during their juvenile stage, regardless of species. Linear mixed effect models were used to quantify recent growth trends (1950–2015) and responses to climate for old and young trees. Climate sensitivity, expressed as radial growth responses to climate during the last three decades, partially differed between species because high spring temperatures enhanced conifer growth, whereas F. sylvatica growth was negatively affected by warmer spring conditions. Furthermore, tree growth was negatively impacted by summer drought in all species. Climate sensitivity differed between young and old trees, with younger trees tending to be more sensitive in P. leucodermis and A. alba, whereas older F. sylvatica trees were more sensitive. In low-elevation Q. cerris stands, limitation of growth due to drought was not related to tree age, suggesting symmetric water competition. We found evidence for a fast-growth trend in young individuals compared with that in their older conspecifics. Notably, old trees tended to have relatively stable growth rates, showing remarkable resistance to climate warming. These responses to climate change should be recognized when forecasting the future dynamics of old-growth forests for their sustainable management.
... This applies especially for forests under pressure from international timber markets. Primary forests or intact secondary forests are particularly sensitive because despite the fact that they are very important carbon reservoirs and biodiversity assets, their status of protection in some EU MS is low (Mikoláš et al. 2019). ...
... Regretabil este faptul că există în momentul de față o rezistență inexplicabilă a oficialităților române din domeniu în a permite efectuarea studiilor în contextul existenței unei birocrații disproporționate. Multe din rezultatele acumulate din 2010 până azi au fost deja publicate în reviste științifice de prestigiu (Cailleret et al. 2018, Vítková Și Al. 2018, Mikoláš et al. 2019, Lábusová et al. 2019 Convenția acoperă întreaga arie geografică a Carpaților și, alături de Convenția Alpilor este al doilea tratat sub-regional pentru protecția și dezvoltarea durabilă regiunilor montane. Obiectivele Convenției Carpaților sunt multiple și toate sunt obligatorii pentru atin-gerea scopului dezvoltării durabile și protecția resurselor naturale precum și a habitatelor. ...
DOI: 10.4316/bf.2021.009 Raportul „Pădurile virgine în inima Europei” (2021), autori; Rainer Luick, Albert Reif, Erika Schneider, Manfred Grossmann și Ecaterina Fodor este o analiză detaliată a importanței, situației actuale și viitorului pădurilor seculare din România. Autorii subliniază marea lor simpatie față de România și abordează importanța ultimelor păduri seculare din Carpații românești pentru moștenirea naturală a Europei. De asemenea, sunt descrise detaliat neputința și lipsa de interes din partea instituțiilor statului în protejarea pădurilor seculare și virgine. Investigațiile asupra corupției profunde și imixtiunii criminale în sectoarele silviculturii și exploatării lemnului scot la iveală interferențe șocante între politică, administrație și corporații. Existând informații asupra tăierilor la scară mare în arii protejate, studiul este centrat pe întrebarea de ce instituțiile UE au avut reacții puține în decursul multor ani la aceste probleme. Autorii cer ca protecția ultimelor păduri virgine din centrul Europei să devină o preocupare a organismelor pan-europene. Acest demers este formulat ca un element cheie pentru Strategia pentru Biodiversitate a Europei până în 2030. România ar deveni astfel un test de litmus asupra șanselor de reușită ale strategiei.
... tree canopy cover >60%) as major changes in canopy foliage cover are readily detected with greenness indices. Over the last decade a number of studies have used this approach to map forest cover at a range of scales from country level to global, including attempts to distinguish between all forests, natural forests and forests that are equivalent to primary forest, including IFL and Hinterland forest (Turubanova et al., 2018, Zhuravleva et al., 2013, Tyukavina et al., 2016, Mikoláš et al., 2019, Hansen et al., 2019, Margono et al., 2014, Potapov et al., 2008. IFL mapping is undertaken globally and by definition those areas include primary forest but also naturally occurring non-forested ecosystems. ...
This report has been prepared by independent experts as a discussion paper for the workshop series with the following three objectives:1.Review and assess definitions relating to primary forests;2.Collate and evaluate datasets and methods currently available for measuring the extent of primary forests; and 3.Provide options for defining, assessing and reporting on primary forests.
... The growth ring series database, includes more than twenty thousand tree core samples, demonstrates that these disturbances form a natural part of the forest development cycle. Results of scientific works are already extensively published (inter alia Cailleret et al. 2018, Vítková et al. 2018, Mikoláš et al. 2019, Lábusová et al. 2019. ...
The report "Virgin forests at the heart of Europe“ by Rainer Luick, Albert Reif, Erika Schneider, Manfred Grossmann & Ecaterina Fodor (2021) is a comprehensive analysis of the importance, situation and future of virgin and old-growth forests in Romania. The authors emphasize their great sympathy with the country and address on many aspects the importance of the remaining virgin forests in the Romanian Carpathians for the European natural heritage. The widespread extensive powerlessness and the lack of interest of state institutions to protect virgin and old forests are also meticulously portrayed. The investigations on a profound corruption and a criminal mixture in the forestry and timber sector that has developed in the interplay of politics, administration and corporate actors is shocking. Knowing about the large-scale loggings in protected areas, the study also picks out as a central theme and question why the EU institutions have shown very few reactions for many years. The authors demand that it must be a pan-European concern to protect the last coherent virgin forests in the more central parts of Europe. This is also formulated as a key element in the EU's Biodiversity Strategy 2030. Romania will be a litmus test as to whether this will succeed.
... The growth ring series database, includes more than twenty thousand tree core samples, demonstrates that these disturbances form a natural part of the forest development cycle. Results of scientific works are already extensively published (inter alia Cailleret et al. 2018, Vítková et al. 2018, Mikoláš et al. 2019, Lábusová et al. 2019. ...
The report (virgin forests at the heart of Europe) provides an overview of the distribution and situation of the last remaining large-scale virgin forests in Central Europe, with a particular focus on Romania. Most people usually associate images of destruction of forests with tropical rain forests. But this also takes place right here on our doorsteps. We in Europe share a global responsibility to protect our unique, irreplaceable natural heritage. These Carpathian forests are some of the last remaining wildernesses, and a precious archive of biodiversity, history, of impressive images and beauty. As consumers, processors and sellers of timber and wood-based products we all have responsibility to stop the pressures placed on these forests, and have the duty to protect this natural heritage for future generations.
Dicranum viride is a bark-dwelling and woodland species listed in Annex II of the ‘EU Habitat Directive’. It occurs mainly in heavily managed forests. The effects of stand age, tree diameter and host tree species on the occurrence of D. viride have been studied at two distinct scales. We suggest that the effects of tree diameter and tree species are mainly related to bark roughness. The occurrence of D. viride on trees with a smooth bark is strongly related to the abundance of Hypnum cupressiforme var. filiforme, which may facilitate establishment of large leaf fragments on smooth bark. Vegetative dispersal and establishment of D. viride are inferred from the current occurrence pattern and biological traits of the species and are hypothesized as having been critical for its survival within managed forests. A straightforward and widely applicable new method of compartment prioritization is provided to facilitate the implementation of modified interventions.
Temporal dynamics of temperate montane primary forests were described based on data from Central-European nature reserves in the 20th century as a long-term cycle involving tree regeneration, growth, maturation, and disintegration. However, the lack of chronosequences focusing on the herbaceous understory has limited our understanding of plant community dynamics within this developmental cycle. To address questions regarding whether the herbaceous understory follows the cyclic trajectory of the tree layer and if the properties of the tree layer drive the dynamics of the herbaceous understory, we investigated a 19-year chronosequence in ten plots (with five sampling periods) within an unmanaged primary beech-fir forest in the Western Carpathians. The vegetation data from the resampled plots, including herb species frequencies and dendrometric variables, covered a significant portion of the developmental cycle of a single plant community type. The results confirmed the cyclical nature of herbaceous understory development in terms of species composition and diversity trajectories, demonstrating transitions between developmental stages. Diversity was highest during the disintegration stage, with a rapid decline towards the growth stage, followed by a slow recovery as it progressed towards the optimum stage. Temporal responses of individual species, along with ordination analyses, allowed for the separation of taxa associated with the disintegration, growth, and optimum stages, as well as the most stable ones throughout the entire cycle. The proportion of therophytes slightly increased after gap-opening events during disintegration, geophytes were most represented during the growth stage, and hemicryptophytes culminated during the optimum stage. The composition of herb species was significantly affected by the above-ground tree biomass (AGTB), which explained 21.4% of the temporal variability. The sum of the diameter at breast height (Sum of DBH) described an additional 7.2%. The relationship between the frequency of the herbaceous understory and AGTB followed a “U” shape, while the relationship with Sum of DBH was negative and linear. The relationship between the herbaceous understory and the tree overstory is likely driven by competition for light, water, and nutrient resources. These findings provide new insights into the temporal relationships between the herbaceous understory and tree layer development, and they may inspire future studies and management strategies aimed at conserving or enhancing biodiversity in temperate forests.
Forest biodiversity studies conducted across Europe use a multitude of forestry terms, often inconsistently. This hinders the comparability across studies and makes the assessment of the impacts of forest management on biodiversity highly context-dependent. Recent attempts to standardize forestry and stand description terminology mostly used a top-down approach that did not account for the perspectives and approaches of forest biodiversity experts. This work aims to establish common standards for silvicultural and vegetation definitions, creating a shared conceptual framework for a consistent study on the effects of forest management on biodiversity. We have identified both strengths and weaknesses of the silvicultural and vegetation information provided in forest biodiversity studies. While quantitative data on forest biomass and dominant tree species are frequently included, information on silvicultural activities and vegetation composition is often lacking, shallow, or based on broad and heterogeneous classifications. We discuss the existing classifications and their use in European forest biodiversity studies through a novel bottom-up and top-driven review process, and ultimately propose a common framework. This will enhance the comparability of forest biodiversity studies in Europe, and puts the basis for effective implementation and monitoring of sustainable forest management policies. The standards here proposed are potentially adaptable and applicable to other geographical areas and could be extended to other forest interventions.
Primary forests provide critical climate regulation functions through the capture and storage of carbon in biomass reservoirs. The capacity of primary forests to sustain biomass levels and the possible consequences of warming-induced increases in extreme disturbances are unresolved questions. We investigated the drivers of biomass accumulation in European primary mountain forests in the Carpathians. We used inventory datasets from a continental-scale survey of remnant primary forests to quantify levels of aboveground live and dead biomass across mixed beech and spruce forest types. We formulated nonlinear regression models to estimate the effects of abiotic and biotic factors, including plot-level disturbance history and tree age using dendrochronological methods. Our analyses show that biomass stocks are comparable with stocks present in other primary forests of temperate regions. Highest mean total biomass in mixed beech forests was in southern landscapes (491 ± 81 Mg ha⁻¹) and western for spruce forests (388 ± 106 Mg ha⁻¹). Forests maintained positive biomass accumulation rates over centuries-long time frames, mean plot-level age peaking at ~ 225 years. We demonstrate that primary forests continue to function as carbon sinks at older ages. Preserving the integrity of unmanaged forests serves as an important climate mitigation strategy.
Old-growth forests (OGF) provide valuable ecosystem services such as habitat provision, carbon sequestration or recreation maintaining biodiversity, carbon storage, or human well-being. Long-term human pressure caused OGFs in Europe to be rare and scattered. Their detailed extent and current status are largely unknown. This review aims to identify potential methods to map temperate old-growth forests (tOGF) by remote sensing (RS) technology, highlights the potentials and benefits, and identifies main knowledge gaps requesting further research. RS offers a wide range of data and methods to map forests and their properties, applicable from local to continental scale. We structured existing mapping approaches in three main groups. First, parameter-based approaches, which are based on forest parameters and usually applied on local to regional scale using detailed data, often from airborne laser scanning (ALS). Second, direct approaches, usually employing machine learning algorithms to generate information from RS data, with high potential for large-area mapping but so far lacking operational applications and related sound accuracy assessment. Finally, indirect approaches integrating various existing data sets to predict OGF existence. These approaches have also been used for large area mapping with a main drawback of missing physical evidence of the identified areas to really hold OGFs as compared to the likelihood of OGF existence. In conclusion, studies dealing with the mapping of OGF using remote sensing are quite limited, but there is a huge amount of knowledge from other forestry-related applications that is yet to be leveraged for OGF identification. We discuss two scenarios, where different data and approaches are suitable, recognizing that one single system cannot serve all potential needs. These may be hot spot identification, detailed area delineation, or status assessment. Further, we pledge for a combined method to overcome the identified limitations of the individual approaches.
Assessing the impacts of natural disturbance on the functioning of complex forest systems are imperative in the context of global change. The unprecedented rate of contemporary species extirpations, coupled with widely held expectations that future disturbance intensity will increase with warming, highlights a need to better understand how natural processes structure habitat availability in forest ecosystems. Standardised typologies of tree-related microhabitats (TreMs) have been developed to facilitate assessments of resource availability for multiple taxa. However, natural disturbance effects on TreM diversity have never been assessed. We amassed a comprehensive dataset of TreM occurrences and a concomitant 300-year disturbance history reconstruction that spanned large environmental gradients in temperate primary forests. We used nonlinear analyses to quantify relations between past disturbance parameters and contemporary patterns of TreM occurrence. Our results reveal that natural forest dynamics, characterised
Tree radial growth is influenced by climatic and various non-climatic factors, which can complicate the extraction of climate signals from tree rings. We investigated the influence of disturbance on tree-ring width (RW) and latewood blue intensity (BI) chronologies of Norway spruce from the Carpathian Mountains to explore the extent to which disturbance can affect temperature signals in tree rings. Overall, ∼15000 high-elevation Norway spruce tree cores from 34 sites grouped into four regions (Slovakia, Ukraine, North and South Romania) were analyzed. The curve intervention detection (CID) method was applied to detect and correct identified disturbance trends. RW chronology structural comparisons were performed among disturbance-affected and disturbance-corrected chronologies for various spatial (regional / site) scales and sampling subsets. Structural comparisons were also performed for RW and BI chronologies developed from separate groups of series (i.e., disturbed, and undisturbed) for five sites exhibiting clear disturbance trends. Temperature sensitivity was assessed for all chronology variants of both parameters. We found that disturbance trends only affected RW chronologies at the site/subset scale with relatively small series replication and were not detected at the regional scale. Unlike RW, BI chronologies were generally unaffected by disturbance. BI data also contained much stronger growing season temperature signals, which appeared to be both spatially and temporally more coherent. Whereas highly replicated and spatially extensive datasets can help minimize or eliminate disturbance trends in RW chronologies, this potential influence should be considered when interpreting climatic signals in tree rings and reconstructing historical climate in weakly replicated periods. On the other hand, BI is a promising alternative tree ring parameter with stronger and more stable growing season temperature signals, whose seemingly disturbance-free chronology structure does not appear to suffer from this ecological bias, and therefore represents a more suitable parameter for dendroclimatological research.
In a world of accelerating changes in environmental conditions driving tree growth, tradeoffs between tree growth rate and longevity could curtail the abundance of large, old trees (LOTs), with potentially dire consequences for biodiversity and carbon storage. However, the influence of tree‐level tradeoffs on forest structure at landscape scales will also depend on disturbances, which shape tree size and age distribution, and on whether LOTs can benefit from improved growing conditions due to climate warming. We analyzed temporal and spatial variation in radial growth patterns from ~ 5000 Norway spruce (Picea abies (L.) H. Karst) live and dead trees from the Western Carpathian primary spruce forest stands. We applied mixed‐linear modeling to quantify the importance of LOT growth histories and stand dynamics (i.e. competition and disturbance factors) on lifespan. Finally, we assessed regional synchronization in radial growth variability over the 20th century, and modelled the effects of stand dynamics and climate on LOTs recent growth trends. Tree age varied considerably among forest stands, implying an important role of disturbance as an age constraint. Slow juvenile growth and longer period of suppressed growth prolonged tree lifespan, while increasing disturbance severity and shorter time since last disturbance decreased it. The highest age was not achieved only by trees with continuous slow growth, but those with slow juvenile growth followed by subsequent growth releases. Growth trend analysis demonstrated an increase in absolute growth rates in response to climate warming, with late summer temperatures driving the recent growth trend. Contrary to our expectation that LOTs would eventually exhibit declining growth rates, the oldest LOTs (> 400 years) continuously increase growth throughout their lives, indicating a high phenotypic plasticity of LOTs for increasing biomass, and a strong carbon sink role of primary spruce forests under rising temperatures, intensifying droughts, and increasing bark beetle outbreaks.
After a revision of Kneiffiella specimens from European old-growth forests in Czech Republic, Slovakia, Croatia and Poland, Kneiffiella altaica was found to have a western distribution far from its type locality at Teletskoye lake in Altai mountains in Russia. Comparing further material from USA, we found a similar species, Kneiffiella subaltaica, which we describe as new to science based on molecular inference of the ITS and 28S DNA sequence and morphology.
Understanding the processes shaping the composition of assemblages at multiple spatial scales in response to disturbance events is crucial for preventing ongoing biodiversity loss and for improving current forest management policies aimed at mitigating climate change and enhancing forest resilience. Deadwood-inhabiting fungi represent an essential component of forest ecosystems through their association with deadwood decomposition and the cycling of nutrients and carbon. Although we have sufficient evidence for the fundamental role of deadwood availability and variability of decay stages for fungal species diversity, the influence of long-term natural disturbance regimes as the main driver of deadwood quantity and quality has not been sufficiently documented. We used a dendroecological approach to analyse the effect of 250-years of historical natural disturbance and structural habitat elements on local (plot-level) and regional (stand-level) species richness of deadwood-inhabiting fungi. We used data collected from 51 study plots within nine best-preserved primary spruce forest stands distributed across the Western Carpathian Mountains. Historical disturbances shaped the contemporary local and regional species richness of fungi, with contrasting impacts of disturbance regime components at different spatial scales. While local diversity of red-listed species has increased due to higher disturbance frequency, regional diversity of all species has decreased due to higher severity historical disturbances. The volume of deadwood positively influenced the species richness of deadwood-inhabiting fungi while canopy openness had a negative impact. The high number of observed rare species highlights the important role of primary forests for biodiversity conservation. From a landscape perspective, we can conclude that the distribution of species from the regional species pool is-at least to some extent-driven by past spatiotemporal patterns of disturbance events. Natural disturbances occurring at higher frequencies that create a mosaic forest structure are necessary for fungal species-especially for rare and endangered taxa. Thus, both the protection of intact forest landscapes and forest management practises that emulate natural disturbance processes are recommended to support habitats of diverse fungal communities and their associated ecosystem functions.
The aim of the study was to compare a patch-mosaic pattern in the old-growth forest stands developed in various climate and soil conditions occurring in different regions of Poland. Based on the assumption, that the patch-mosaic pattern in the forest reflect the dynamic processes taking place in it, and that each type of forest ecosystem is characterized by a specific regime of natural disturbances, the following hypotheses were formulated: (i) the patches with a complex structure in stands composed of latesuccessional, shade-tolerant tree species are more common than those composed of early-successional, light-demanding ones, (ii) the patch-mosaic pattern is more heterogeneous in optimal forest site conditions than in extreme ones, (iii) in similar site conditions differentiation of the stand structure in distinguished patches is determined by the successional status of the tree species forming a given patch, (iv) the successional trends leading to changes of species composition foster diversification of the patch structure, (v) differentiation of the stand structure is negatively related to their local basal area, especially in patches with a high level of its accumulation. Among the best-preserved old-growth forest remaining under strict protection in the Polish national parks, nineteen research plots of around 10 ha each were selected. In each plot, a grid (50 × 50 m) of circular sample subplots (with radius 12,62 m) was established. In the sample subplots, species and diameter at breast height of living trees (dbh ≥ 7 cm) were determined. Subsequently, for each sample subplot, several numerical indices were calculated: local basal area (G), dbh structure differentiation index (STR), climax index (CL) and successional index (MS). Statistical tests of Kruskal- Wallis, Levene and Generalized Additive Models (GAM) were used to verify the hypotheses. All examined forests were characterized by a large diversity of stand structure. A particularly high frequency of highly differentiated patches (STR > 0,6) was recorded in the alder swamp forest. The patch mosaic in the examined plots was different – apart from the stands with a strongly pronounced mosaic character (especially subalpine spruce forests), there were also stands with high spatial homogeneity (mainly fir forests). The stand structure in the distinguished patches was generally poorly related to the other studied features. Consequently, all hypotheses were rejected. These results indicate a very complex, mixed pattern of forest natural dynamics regardless of site conditions. In beech forests and lowland multi-species deciduous forests, small-scale disturbances of the gap dynamics type dominate, which are overlapped with less frequent medium-scale disturbances. In more difficult site conditions, large-scale catastrophic disturbances, which occasionally appear in communities formed under the influence of gap dynamics (mainly spruce forests) or cohort dynamics (mainly pine forests), gain importance.
Natural disturbances strongly influence forest structural dynamics, and subsequently stand structural heterogeneity, biomass, and forest functioning. The impact of disturbance legacies on current forest structure can greatly influence how we interpret drivers of forest dynamics. However, without clear insight into forest history, many studies default to coarse assumptions about forest structure, for example, whether forests are even or unevenly aged. The aim of this study was to analyze the effects of past disturbances on the current diameter distributions of Norway spruce (Picea abies (L.) Karst.)-dominated landscapes throughout the Carpathian Mountains. Our dendroecological dataset comprises tree cores from 339 plots (7,845 total tree cores), nested within 28 primary forest stands, known to vary greatly in the severity of historical disturbances. Our analyses revealed that historical disturbances had a strong and significant effect on the current diameter distribution shapes at the plot level. We demonstrated that mixed-severity disturbance regimes were more frequent and create a complex pattern of diameter distributions at the plot and stand scale. Here, we show that high severity disturbance was associated with unimodal diameter distributions, while low and moderate severity was associated with the reverse J-shaped distribution. This is a result of complex disturbance patterns, with structural biological legacies. Our results will have important management implication in the context of tree size heterogeneity, biomass storage, and productivity as influenced by natural disturbances. Lastly, these results demonstrate that structural changes may arise as consequences of changing disturbance regime associated with global change.
The impact of forest management on biodiversity is difficult to scrutinize along gradients of management. A step towards analyzing the impact of forest management on biodiversity is comparisons between managed and primary forests. The standardized typology of tree-related microhabitats (TreMs) is a multi-taxon indicator used to quantify forest biodiversity. We aim to analyze the influence of environmental factors on the occurrence of groups of TreMs by comparing primary and managed forests. We collected data for the managed forests in the Black Forest (Germany) and for the primary forests in the Western (Slovakia) and Southern Carpathians (Romania). To model the richness and the different groups of TreMs per tree, we used generalized linear mixed models with diameter at breast height (DBH), altitude, slope and aspect as predictors for European beech ( Fagus sylvatica (L.)) , Norway spruce ( Picea abies (L.) ) and silver fir ( Abies alba (Mill.) ) in primary and managed temperate mountain forests. We found congruent results for overall richness and the vast majority of TreM groups. Trees in primary forests hosted a greater richness of all and specific types of TreMs than individuals in managed forests. The main drivers of TreMs are DBH and altitude, while slope and aspect play a minor role. We recommend forest and nature conservation managers to focus: 1) on the conservation of remaining primary forests and 2) approaches of biodiversity-oriented forest management on the selection of high-quality habitat trees that already provide a high number of TreMs in managed forests based on the comparison with primary forests.
When management for old-growth characteristics in eastern forests first began to be discussed in the late twentieth century, there was skepticism from some quarters as to whether it was a desirable or even a feasible idea. Old growth will recover on its own. Why not just let nature take its course? There were also those who saw little value in managing for old-growth features, perceiving this as a threat to more traditional management objectives (Puettmann et al. 2015). Since that time, concepts of managing for stand structural complexity, in ways that encourage some characteristics of old-growth forests, have caught on in a variety of contexts (Bauhus et al. 2009; Puettmann et al. 2009). In many ways this shift mirrors how the profession has grown to embrace multifunctional forestry broadly defined (Gustafsson et al. 2012). Old-growth silviculture increasingly has a place within this framework, filling the niche of enhancing the representation of late successional forests on landscapes where they are now vastly underrepresented relative to their abundance on landscapes prior to Euro-American settlement (Lorimer and White 2003; Rhemtulla et al. 2007). The working hypothesis is that this type of management will contribute to sustainable forest practices focused on providing a broad array of ecosystem goods and services, including those associated with late successional systems. And in recent decades there has been increasing interest in old-growth restoration more narrowly and management for older forest characteristics in working forests generally, both in terms of experimental research (e.g., Keeton 2006; Gronewold et al. 2010; Forrester et al. 2013; Palik et al. 2014) and practical applications (Hagenbuch et al. 2013; Fassnacht et al. 2015).
Forests provide numerous ecosystem services, such as timber yields, biodiversity protection and climate change mitigation. The type of management has an effect on the provision of these services. Often the demands for these services can lead to conflict – wood harvest can negatively impact biodiversity and climate change mitigation capacity. Although forest management differences are important, spatially explicit data is lacking, in particular on a global scale. We present here a first systematic approach which integrates existing data to map forest management globally through downscaling national and subnational forest data. In our forest management classification, we distinguished between two levels of forest management, with three categories each. Level 1 comprised primary, naturally regrown and planted forests. Level 2 distinguished between different forest uses. We gathered documented locations, where these forest categories were observed, from the literature and a database on ecological diversity. We then performed multinomial logit regression and estimated the effect of 21 socio-economic and bio-physical predictor variables on the occurrence of a forest category. Model results on significance and effect direction of predictor variables were in line with findings of previous studies. Soil and environmental properties, forest conditions and accessibility are important determinants of the occurrence of forest management types. Based on the model results, likelihood maps were calculated and used to spatially allocate national extents of level 1 and level 2 forest categories. When compared to previous studies, our maps showed higher agreement than random samples. Deviations between observed and predicted plantation locations were mostly below 10 km. Our map provides an estimation of global forest management patterns, enhancing previous methodologies and making the best use of data available. Next to having multiple applications, for example within global conservation planning or climate change mitigation analyses, it visualizes the currently available data on forest management on a global level.
The circumboreal forest encompasses diverse landscape structures, dynamics and forest age distributions determined by their physical setting, and historical and current disturbance regimes. However, due to intensifying forest utilisation, and in certain areas due to increasing natural disturbances, boreal forest age-class structures have changed rapidly, so that the proportion of old forest has substantially declined, while that of young post-harvest and post-natural-disturbance forest proportions have increased. In the future, with a warming climate in certain boreal regions, this trend may further be enhanced due to an increase in natural disturbances and large-scale use of forest biomass to replace fossil-based fuels and products. The major drivers of change of forest age class distributions and structures include the use of clearcut short-rotation harvesting, more frequent and severe natural disturbances due to climate warming in certain regions. The decline in old forest area, and increase in managed young forest lacking natural post-disturbance structural legacies, represent a major transformation in the ecological conditions of the boreal forest beyond historical limits of variability. This may introduce a threat to biodiversity, ecosystem resilience and long-term adaptive capacity of the forest ecosystem. To safeguard boreal forest biodiversity and ecosystem functioning, and to maintain the multiple services provided to societies by this forest biome, it is pivotal to maintain an adequate share and the ecological qualities of young post-disturbance stages, along with mature forest stages with old-growth characteristics. This requires management for natural post-disturbance legacy structures, and innovative use of diverse uneven-aged and continuous cover management approaches to maintain critical late-successional forest structures in landscapes.
Aim
Primary forests have high conservation value but are rare in Europe due to historic land use. Yet many primary forest patches remain unmapped, and it is unclear to what extent they are effectively protected. Our aim was to (1) compile the most comprehensive European‐scale map of currently known primary forests, (2) analyse the spatial determinants characterizing their location and (3) locate areas where so far unmapped primary forests likely occur.
Location
Europe.
Methods
We aggregated data from a literature review, online questionnaires and 32 datasets of primary forests. We used boosted regression trees to explore which biophysical, socio‐economic and forest‐related variables explain the current distribution of primary forests. Finally, we predicted and mapped the relative likelihood of primary forest occurrence at a 1‐km resolution across Europe.
Results
Data on primary forests were frequently incomplete or inconsistent among countries. Known primary forests covered 1.4 Mha in 32 countries (0.7% of Europe’s forest area). Most of these forests were protected (89%), but only 46% of them strictly. Primary forests mostly occurred in mountain and boreal areas and were unevenly distributed across countries, biogeographical regions and forest types. Unmapped primary forests likely occur in the least accessible and populated areas, where forests cover a greater share of land, but wood demand historically has been low.
Main conclusions
Despite their outstanding conservation value, primary forests are rare and their current distribution is the result of centuries of land use and forest management. The conservation outlook for primary forests is uncertain as many are not strictly protected and most are small and fragmented, making them prone to extinction debt and human disturbance. Predicting where unmapped primary forests likely occur could guide conservation efforts, especially in Eastern Europe where large areas of primary forest still exist but are being lost at an alarming pace.
As the terrestrial human footprint continues to expand, the amount of native forest that is free from significant damaging human activities is in precipitous decline. There is emerging evidence that the remaining intact forest supports an exceptional confluence of globally significant environmental values relative to degraded forests, including imperilled biodiversity, carbon sequestration and storage, water provision, indigenous culture and the maintenance of human health. Here we argue that maintaining and, where possible, restoring the integrity of dwindling intact forests is an urgent priority for current global efforts to halt the ongoing biodiversity crisis, slow rapid climate change and achieve sustainability goals. Retaining the integrity of intact forest ecosystems should be a central component of proactive global and national environmental strategies, alongside current efforts aimed at halting deforestation and promoting reforestation.
8000 years ago, prior to Neolithic agriculture, Europe was mostly a wooded continent. Since then, its forest cover has been progressively fragmented, so that today it covers less than half of Europe's land area, in many cases having been cleared to make way for fields and pasture-land. Establishing the origin of Europe's current, more open land-cover mosaic requires a long-term perspective, for which pollen analysis offers a key tool. In this study we utilise and compare three numerical approaches to transforming pollen data into past forest cover, drawing on >1000 14C-dated site records. All reconstructions highlight the different histories of the mixed temperate and the northern boreal forests, with the former declining progressively since ~6000 years ago, linked to forest clearance for agriculture in later prehistory (especially in northwest Europe) and early historic times (e.g. in north central Europe). In contrast, extensive human impact on the needle-leaf forests of northern Europe only becomes detectable in the last two millennia and has left a larger area of forest in place. Forest loss has been a dominant feature of Europe's landscape ecology in the second half of the current interglacial, with consequences for carbon cycling, ecosystem functioning and biodiversity.
Determining the drivers of shifting forest disturbance rates remains a pressing global change issue. Large-scale forest dynamics are commonly assumed to be climate driven, but appropriately scaled disturbance histories are rarely available to assess how disturbance legacies alter subsequent disturbance rates and the climate sensitivity of disturbance. We compiled multiple tree-ring based disturbance histories from primary Picea abies forest fragments distributed throughout five European landscapes spanning the Bohemian Forest and the Carpathian Mountains. The regional chronology includes 11 595 tree cores, with ring dates spanning the years 1750 to 2000, collected from 560 inventory plots in 37 stands distributed across a 1000 km geographic gradient, amounting to the largest disturbance chronology yet constructed in Europe. Decadal disturbance rates varied significantly through time and declined after 1920, resulting in widespread increases in canopy tree age. Approximately 75% of current canopy area recruited prior to 1900. Long-term disturbance patterns were compared to an historical drought reconstruction, and further linked to spatial variation in stand structure and contemporary disturbance patterns derived from LANDSAT imagery. Historically, decadal Palmer drought severity index minima corresponded with higher rates of canopy removal. The severity of contemporary disturbances increased with each stand's estimated time since last major disturbance, increased with mean diameter and declined with increasing within-stand structural variability. Reconstructed spatial patterns suggest that high small-scale structural variability has historically acted to reduce large-scale susceptibility and climate sensitivity of disturbance. Reduced disturbance rates since 1920, a potential legacy of high 19th century disturbance rates, have contributed to a recent region-wide increase in disturbance susceptibility. Increasingly common high-severity disturbances throughout primary Picea forests of Central Europe should be reinterpreted in light of both legacy effects (resulting in increased susceptibility) and climate change (resulting in increased exposure to extreme events). This article is protected by copyright. All rights reserved.
In July 2016, the European Commission (EC) published a legislative proposal for
incorporating greenhouse gas emissions and removals due to Land Use, Land Use Change and
Forestry (LULUCF) into its 2030 Climate and Energy Framework. The Climate and Energy Framework
aims at a total emission reduction of 40% by 2030 for all sectors together as part of the Paris Agreement.
The LULUCF proposal regulates a “no debit” target for LULUCF (Forests and Agricultural soils),
and regulates the accounting of any additional mitigation potential that might be expected of it.
We find that the forest share of the LULUCF sector can achieve much more than what is in the
regulation now. We elaborate a strategy for unlocking European Union (EU) forests and forest sector
potential based on the concept of “climate smart forestry” (CSF). We find that to-date, European
policy has not firmly integrated forest potential into the EU climate policy framework. Nor have
climate objectives been firmly integrated into those of the forest and forest sector at either the EU or
national level. Yet a wide range of measures can be applied to provide positive incentives for more
firmly integrating these climate objectives into the forest and forest sector framework. With the right
set of incentives in place at EU and Member States levels, we find the current literature supports the
view that the EU has the potential to achieve an additional combined mitigation impact through CSF
of 441 Mt CO2/year by 2050. In addition, CSF, through reducing and/or removing greenhouse gas
emissions, adapting and building forest resilience, and sustainably increasing forest productivity and
incomes, tackles multiple policy goals.
Identification of forest stands with priority for the conservation of biodiversity is of particular importance in landscapes with a long cultural and agricultural history, such as Central Europe. A group of species with a high indicator value for the naturalness of forest ecosystems are saproxylic insects. Some of these species, especially within the order Coleoptera, have been described as primeval forests relicts. Here, we compiled a list of 168 “primeval forest relict species” of saproxylic beetles based on expert knowledge. These species can serve as focal and umbrella species for forest conservation in Central Europe. They were selected because of their dependence on the continuous presence of primeval forest habitat features, such as over-mature trees, high amounts of dead wood, and dead wood diversity, as well as their absence in managed Central European forests. These primeval forest relict species showed a moderately strong clumping pattern within the phylogeny of beetles, as indicated by phylogenetic signal testing using the D-statistic. When we controlled for phylogenetic relatedness, an ordinal linear model revealed that large body size and preference for dead wood and trees of large diameter are the main characteristics of these species. This list of species can be used to identify forest stands of conservation value throughout Central Europe, to prioritize conservation and to raise public awareness for conservation issues related to primeval forests.
European natural mountain Norway spruce (Picea abies) forests are currently subject to extensive disturbances. An improved understanding of the self-regulated regenerative capacity of this forest type is therefore needed. We used the last remnant of natural mountain Norway spruce forests in central northwestern Europe (BNF Brocken natural forest), to analyze (1) the diversity of structure and age distribution of the tree population and (2) the effect of disturbances on self-regulated tree regeneration over the last 264 years. To this end, we combined an assessment of stand structure with dendrochronological investigations and a review of disturbance history. We hypothesized that BNF exhibits a high diversity of tree ages and dimensions and that recruitment and survival of tree regeneration were largely independent from disturbances. BNF showed a high structural and age diversity. Disturbances exhibited no regular temporal pattern. Their effect on tree regeneration was rather complex and changed with observation period. Impeding and facilitating effects of past disturbances on recruitment were significant from 1736 to 1910. From 1911 until 2000, recruitment decoupled from preceding disturbances. Subsequent disturbances facilitated survival of established trees from 1736 to 1820, while afterward no significant influence could be proved. Our study showed that in the course of self-regulated development the tree population of BNF has gradually acquired, or maintained, a diverse structure. Disturbances served as an important driver of diversification. We concluded that increasing deadwood availability and limiting browsing are the key to securing immediate regeneration.
Biodiversity not only responds to environmental change, but has been shown to be one of the key drivers of ecosystem function and service delivery. Forest soil biodiversity is also governed by these principles, the structure of soil biological communities is clearly determined by spatial, temporal and hierarchical factors. Global environmental change, together with land-use change and forest ecosystem management, impacts the aboveground structure and composition of European forests. Due to the close link between the above- and belowground parts of forest ecosystems, we know that soil biodiversity is also impacted. However, very little is known about the nature of these impacts; effects they have on the overall level of biodiversity, the functions it fulfills, and on the future stability of forests and forest soils. Even though much remains to be learned about the relationships between soil biodiversity and forest ecosystem functionality, it is clear that better effort needs to be made to preserve existing soil biodiversity and forest conservation strategies taking soils into account must be considered.
Habitat loss and fragmentation can negatively impact the persistence of dispersal-limited lichen species with narrow niches. Rapid change in microclimate due to canopy dieback exposes species to additional stressors that may limit their capacity to survive and colonize. We studied the importance of old trees as micro-refuges and microclimate stability in maintaining lichen survival and diversity. The study was situated in mountain Norway spruce (Picea abies) forests of the Gorgany Mountains of the Ukrainian Carpathian mountain belt. Lichens were collected on 13 circular study plots (1000 m²). Dendrochronological methods were used to reconstruct age structure and maximum disturbance event history. A linear mixed effects model and general additive models were used to explain patterns and variability of lichens based on stand age and disturbance history for each plot. Tree age was the strongest variable influencing lichen diversity and composition. Recent (<80 years ago) severely disturbed plots were colonized only by the most common species, however, old trees (>200 years old) that survived the disturbances served as microrefuges for the habitat-specialized and/or dispersal limited species, thus epiphytic lichen biodiversity was markedly higher on those plots in comparison to plots without any old trees. Most species were able to survive microclimatic change after disturbances, or recolonize disturbed patches from surrounding old-growth forests. We concluded that the survival of old trees after disturbances could maintain and/or recover large portions of epiphytic lichen biodiversity even in altered microclimates.
Too many roads
Roads have done much to help humanity spread across the planet and maintain global movement and trade. However, roads also damage wild areas and rapidly contribute to habitat degradation and species loss. Ibisch et al. cataloged the world's roads. Though most of the world is not covered by roads, it is fragmented by them, with only 7% of land patches created by roads being greater than 100 km ² . Furthermore, environmental protection of roadless areas is insufficient, which could lead to further degradation of the world's remaining wildernesses.
Science , this issue p. 1423
Under the coordination of The Ministry of Environment, Waters
and Forests, about 24000 ha of primeval beech forests located in 8 natural
protected area from the Romanian Carpathians were included for inscription
into the World Heritage List to extend the „Primeval Beech Forests of
the Carpathians and the Ancient Beech Forests of Germany” (1133bis). The
extended World Heritage property is proposed to carry the joint new name:
„Primeval Beech Forests of the Carpathians and Other Regions of Europe”.
Supported by 13 European countries (Romania included), the nomination
proposes to establish a transnational serial UNESCO property, with a surface
of more that 95000 ha, that reunites the most representative and well
preserved beech forests from the natural areal of this species in order to
illustrate the ecological process of extension - that is in progress at present
- of beech on the European continent. The process of choosing these canditate
sites was thought for completing the existent sites and for providing
arguments and reflecting better on the extension of species distribution at
the level of Europe. At the end of January 2016, Austria, the coordinator
country of the nomination process at the international level transmitted the
common dossier for the nomination to the committee of evaluation of UNESCO
World Heritage List.
Existing terminologies since the late 1980’s are reviewed revealing gaps, inconsistencies and overlapping
definitions. Many terms have been used very differently by different organisations with semi-natural forest
being the worst example. It has variously been used for any kind of forest except exotic plantation. A new
hierarchical terminology is proposed based on the work of many authors, persons and organisations working
with this issue during the 1990’s. Fourteen mutually exclusive levels of naturalness are delimited, defined,
named and grouped, including virgin forest, old-growth, newly untouched forest, exploited natural forest,
native plantation, exotic plantation and exotic self-sown forest. Consistent definitions for groups of levels
and for qualifying features are also presented, e.g. for natural forest, planted forest, native forest, exotic
forest, primary forest, minimum-intervention forest, ancient woodland and grazed forest. The definition of
natural forest follows UNCED, FAO, EU and the World Bank. For other terms official sources like FAO’s
Forest Resources Assessment have been followed as far as possible.
ContextDistribution and connectivity of suitable habitat for species of conservation concern is critical for effective conservation planning. Capercaillie (Tetrao urogallus), an umbrella species for biodiversity conservation, is increasingly threatened because of habitat loss and fragmentation. Objective
We assessed the impact of drastic changes in forest management in the Carpathian Mountains, a major stronghold of capercaillie in Europe, on habitat distribution and connectivity. Methods
We used field data surveys with a forest disturbance dataset for 1985–2010 to map habitat suitability, and we used graph theory to analyse habitat connectivity. ResultsClimate, topography, forest proportion and fragmentation, and the distance to roads and settlements best identified capercaillie presence. Suitable habitat area was 7510 km2 in 1985; by 2010, clear-cutting had reduced that area by 1110 km2. More suitable habitat was lost inside protected areas (571 km2) than outside (413 km2). Habitat loss of 15 % reduced functional connectivity by 33 % since 1985. Conclusions
Forest management, particularly large-scale clear-cutting and salvage logging, have substantially diminished and fragmented suitable capercaillie habitat, regardless of the status of forest protection. Consequently, larger areas with suitable habitat are now isolated and many patches are too small to sustain viable populations. Given that protection of capercaillie habitat would benefit many other species, including old-growth specialists and large carnivores, conservation actions to halt the loss of capercaillie habitat is urgently needed. We recommend adopting policies to protect natural forests, limiting large-scale clear-cutting and salvage logging, implementing ecological forestry, and restricting road building to reduce forest fragmentation.
Europe's managed forests contribute to warming
For most of the past 250 years, surprisingly it seems that Europe's managed forests have been a net source of carbon, contributing to climate warming rather than mitigating it. Naudts et al. reconstructed the history of forest management in Europe in the context of a land-atmosphere model. The release of carbon otherwise stored in litter, dead wood, and soil carbon pools in managed forests was one key factor contributing to climate warming. Second, the conversion of broadleaved forests to coniferous forests has changed the albedo and evapotranspiration of those forests, also leading to warming. Thus, climate change mitigation policies in Europe and elsewhere may need to consider changes in forest management.
Science , this issue p. 597
The work presents the conceptual information about the National Forest Inventory and Monitoring in Slovakia. It introduces some methodological approaches to the field data collection (determination of tree heights by two-phase method, regression formulas for tree volumes and assortments of forest tree species, quantification of deadwood volume in sample plots) and biometrical models prepared for data processing and generalisation of the results. The design and conception of Slovak National Forest Inventory and Monitoring were set with the aim to enable providing complex and integrated information about the state and changes of production and ecological characteristics of the forest ecosystems.