Tomáš Hlásny

Climate change increases the drought risk in Central European forests: What are the options for adaptation?

Abstract The paper presents information on the projected drought exposure of Central Europe, describes the anticipated dynamics of the regional forests, and identifies measures facilitating the adaptation of forests to climate change-induced drought risk. On the basis of an ensemble of climate change scenarios we expect substantial drying in southern Slovakia and Hungary, while such trends were found to be less pronounced for the Czech Republic and Austria. In response to these climate trajectories, a change in species composition towards a higher share of drought tolerant species as well as the use of drought resistant provenances are identified as paramount actions in forest adaptation in the region. Adaptation to aggravating climate change may need to use artificial regeneration to enrich local gene pools and increase the drought tolerance of stands. Increasing risks from pests, pathogens and other disturbances are expected as a result of more frequent and severe droughts, underlining the need to put a stronger focus on risk management principles rather than on indicators of productivity in silviculture and forest planning. A consolidation of disturbance monitoring systems and a broader use of pest dynamics and hazard rating models are paramount tools to facilitate this adaptation process in forest management. The effectiveness of all the suggested measures needs to be controlled by efficient forest monitoring systems, the consolidation of which seems to be a timely task. Systematic and long-term implementation of the presented measures should increase forest stability and resilience, and further secure the sustainable provision of ecosystem services under climate change. Abstrakt V článku sú prezentované informácie o očakávanom vývoji sucha v oblasti strednej Európy, je opísaná možná dynamika lesov v podmienkach zmeny klímy, a je vypracovaný systém opatrení umožňujúcich adaptáciu lesov na zmenu klímy. Na základe kolekcie scenárov zmeny klímy bol identifikovaný výrazný nárast intenzity sucha v oblastiach južného Slovenska a Maďarska, zatiaľ čo v oblasti Českej republiky a Rakúska bola zmena relatívne nevýrazná. S ohľadom na tento vývoj predstavuje úprava drevinového zloženia smerom k vyššiemu zastúpeniu sucho tolerujúcich drevín a širšiemu využívaniu proveniencií rezistentných voči suchu jedno zo základných adaptačných opatrení. V prípade výrazných zmien klímy narastá význam umelej obnovy, ktorá predstavuje nástroj na zlepšovanie druhovej a genetickej diverzity porastov a zvyšovanie ich tolerancie voči suchu. Narastajúci vplyv škodcov súvisiaci s rastúcim vplyvom sucha a ďalších abiotických činiteľov naznačuje potrebu orientovať pestovanie a hospodársku úpravu lesa viac na manažment rizík ako na maximalizáciu produkcie. Konsolidácia systémov monitoringu škodlivých činiteľov a širšie využívanie modelov dynamiky škodcov a hodnotenia rizík patria medzi ďalšie dôležité opatrenia podporujúce adaptáciu lesov na zmenu klímy. Všetky uvedené opatrenia musia byť podporené informáciami získanými na základe dlhodobého monitoringu lesa, ktorý však vyžaduje urýchlenú konsolidáciu. Systematická a dlhodobá realizácia prezentovaných opatrení podporí stabilitu a rezilienciu lesov a vytvorí predpoklady pre udržateľné poskytovanie ekosystémových služieb a funkcií v podmienkach zmeny klímy.

Persisting bark beetle outbreak indicates the unsustainability of secondary Norway spruce forests: case study from Central Europe

Abstract• ContextSecondary Norway spruce forests in the Western Beskids are among the most damaged forests in Europe. Although spruce bark beetle (Ips typographus) has been recently causing large-scale damage to these forests, our understanding of I. typographus dynamics in this environment is inadequate for evaluating forest sustainability.• AimThis study aims to evaluate the patterns of damage caused by I. typographus to spruce forests with compromised ecological stability.• MethodsForest infestation by I. typographus was inferred from sanitary felling data collected from 1998 to 2004. Stand and site data were obtained from forest management plans. Spatial-dependence analysis, ordinary kriging and neural network-based regression modelling were used to investigate the patterns of infestation and the casual relationships in the studied ecosystem.• ResultsI. typographus long-distance dispersal substantially decreased with outbreak culmination. The spread of infestation was only weakly related to stand and site parameters. Infestations spread isotropically at the stand and patch level but directionally at the regional scale.• ConclusionsThe large-scale spread of infestation can be explained by the uniform age and species composition of the investigated forests and by the ability of populations to overwhelm suboptimal trees. The observations presented here suggest that secondary spruce forests in Europe may be unsustainable due to unprecedented bark beetle outbreaks, which can be further amplified by changing climate.

Insect Pests as Climate Change Driven Disturbances in Forest Ecosystems

Climate change is generally agreed to have a profound impact on forest structure and its dynamics (Aber et al. 2001; Ayres and Lombardero 2000; Dale et al. 2000, 2001). As trees can live from decades to centuries, rapid changes of climate are also expressed through alterations of the disturbance regime (Franklin et al. 2002; He et al. 1999).

How does soil water potential limit the seasonal dynamics of sap flow and circumference changes in European beech

Abstract We focus on the analysis of sap flow and stem circumference changes in European beech (Fagus sylvatica, L.) in relation to available soil water and weather conditions during the growing seasons 2012 and 2013. The objective was to examine how soil water potential affects growth and transpiration of a mature beech stand situated at the lower distributional limit of beech in Slovakia. To be able to evaluate beech response to soil water shortage, we irrigated a group of 6 trees during the period of pronounced drought, while the control group of other 6 trees remained exposed to actual weather conditions. Mean air temperatures of both seasons were considerably above the long-term average and the temporal pattern of precipitation differed between the years. During the whole growing season 2012, beech samples transpired an average volume of 6.9 m3 of water in the control and 7.7 m3 in the irrigated group. A slightly higher average volume was found in the growing season 2013 under both treatments (7.7 m3 in control and 10.5 m3 in irrigated trees). In the drought period 2012, when the irrigation experiment was commenced, the sap flow in the control group was reduced by 30% as compared with the irrigated group. In 2013, a 38.1% difference in sap flow was observed between the groups. Sap flow in the non-irrigated trees decreased with reducing soil moisture, and ceased at soil water potential -0.6 MPa. In both treatments and years, we found significant correlations between hourly sap flow and investigated weather variables. A reduction in stem circumferences of the control trees, which was observed during stem shrinkage phase, was up to 19% in 2012 and 10% in 2013. We conclude that stem circumference shrinkage during the peak of soil drought was induced by the cessation in the sap flow process. Abstrakt V práci sa zameriavame na analýzu transpiračného prúdu a zmien obvodov kmeňa buka lesného (Fagus sylvatica L.) vo vzťahu k disponibilnej pôdnej vode a meteorologickým podmienkam vo vegetačnom období 2012 a 2013. Cieľom bolo zistiť, ako vodný potenciál pôdy ovplyvňuje rast a transpiráciu bukového porastu na spodnej hranici výskytu buka na Slovensku. Počas periódy pôdneho sucha bola skupina 6 jedincov buka intenzívne zavlažovaná, zatiaľ čo kontrolná skupina 6 jedincov bola vystavená aktuálnym meteorologickým podmienkam. Vo vegetačnej sezóne oboch rokov boli zistené nadpriemerné mesačné teploty vzduchu. Časové rozloženie zrážok počas vegetačnej sezóny sa medzi rokmi líšilo. Vo vegetačnom období 2012, jedince buka transpirovali priemerne 6,9 m3 vody v kontrolnej skupine a 7,7 m3 v zavlažovanej skupine. V roku 2013 bol v oboch skupinách zistený vyšší objem transpiračného prúdu (priemerne 7,7 m3 v kontrolnej a 10,5 m3 v zavlažovanej skupine). V priebehu zavlažovacieho experimentu v období sucha 2012 bol transpiračný prúd jedincov kontrolnej skupiny v porovnaní so zavlažovanými jedincami buka nižší o 30 %. V roku 2013 bol medzi skupinami pozorovaný rozdiel 38,1 %. Vplyv pôdneho sucha na transpiráciu sa začal významne prejavovať pri hodnote vodného potenciálu pôdy −0,6 MPa. V oboch skupinách aj rokoch bol preukázaný štatisticky významný vzťah medzi hodinovými údajmi transpiračného prúdu a väčšinou skúmaných meteorologických charakteristík. Počas fázy zmršťovania kmeňov v období sucha, bol u jedincov kontrolnej skupiny pozorovaný 19 % pokles na obvode stromov v roku 2012 a 10 % v roku 2013. Na základe našich pozorovaní môžeme konštatovať, že kontrakcie obvodov kmeňov v období vrcholiaceho pôdneho sucha boli vyvolané útlmom v procese transpiračného prúdu.

Bridging the gap between climate models and impact studies: the FORESEE Database

Studies on climate change impacts are essential for identifying vulnerabilities and developing adaptation options. However, such studies depend crucially on the availability of reliable climate data. In this study, we introduce the climatological database called FORESEE (Open Database for Climate Change Related Impact Studies in Central Europe), which was developed to support the research of and adaptation to climate change in Central and Eastern Europe: the region where knowledge of possible climate change effects is inadequate. A questionnaire‐based survey was used to specify database structure and content. FORESEE contains the seamless combination of gridded daily observation‐based data (1951–2013) built on the E‐OBS and CRU TS datasets, and a collection of climate projections (2014–2100). The future climate is represented by bias‐corrected meteorological data from 10 regional climate models (RCMs), driven by the A1B emission scenario. These latter data were developed within the frame of the ENSEMBLES FP6 project. Although FORESEE only covers a limited area of Central and Eastern Europe, the methodology of database development, the applied bias correction techniques, and the data dissemination method, can serve as a blueprint for similar initiatives.

Sustainable forest management in a mountain region in the Central Western Carpathians, northeastern Slovakia: the role of climate change

European forestry is facing many challenges, including the need to adapt to climate change and an unprecedented increase in forest damage. We investigated these challenges in a Norway spruce-dominated mountain region in Central Europe. We used the model Sibyla to explore forest biomass production to the year 2100 under climate change and under two alternative management systems: the currently applied management (CM), which strives to actively improve the forest’s adaptive capacity, and no management (NM) as a reference. Because biodiversity is thought to have mostly positive effects on the adaptive capacity of forests and on the quality of ecosystem services, we explored how climate change and management affect indicators of biodiversity. We found a differential response across the elevation-climatic gradient, including a drought-induced decrease in biomass production over large areas. With CM, the support of non-spruce species and the projected improvement of their growth increased tree species diversity. The promotion of species with higher survival rates led to a decrease in forest damage relative to both the present conditions and NM. NM preserved the high density of over-matured spruce trees, which caused forest damage to increase. An abundance of dead wood and large standing trees, which can increase biodiversity, increased with NM. Our results suggest that commercial spruce forests, which are not actively adapted to climate change, tend to preserve their monospecific composition at a cost of increased forest damage. The persisting high rates of damage along with the adverse effects of climate change make the prospects of such forests uncertain.

Effect of deforestation on watershed water balance: hydrological modelling-based approach / Vplyv odlesnenia na vodnú bilanciu povodia: prístup na báze hydrologického modelovania

Abstract Changes in land cover, including deforestation, can have significant effect on watershed hydrology. We used hydrological model with distributed parameters to evaluate the effect of simulated deforestation on water balance components in the watershed Ulička (97 km2, 84.3% forest cover) located in the eastern Slovakia. Under the current land cover, average interception accounted for 21.1% of the total precipitation during the calibration period 2001-2013. Most of the precipitation (77%) infiltrated into the soil profile, and less than half of this amount percolated into the ground water aquifer. The surface runoff accounted for 1.2% of the total precipitation only, while the interflow accounted for ca. 12%. The largest proportion of the precipitation contributed to the base flow (23%). Watershed`s deforestation induced significant decrease in the interception and evapotranspiration (by 76% and 12%, respectively). At the same time, total runoff, surface runoff, interflow and base flow increased by 20.4, 38.8, 9.0 and 25.5%, respectively. Daily discharge increased by 20%. The deforestation significantly increased peak discharge induced by a simulated extreme precipitation event with the recurrence interval of 100 years. In the deforested watershed, the peak discharge was higher by 58% as compared with the current land cover. Peak discharge occurred in 432 minutes with the current land cover and in 378 minutes with deforestation, after the precipitation event had started. The presented assessment emphasized the risk of adverse effect of excessive deforestation on watershed hydrology. At the same time, the developed model allows testing the effect of other land cover scenarios, and thus supports management in the investigated watershed. Abstrakt Zmeny vo vegetačnom kryte a využívaní krajiny, vrátane odlesnení, môžu mať významný vplyv na hydrologickú bilanciu povodí. V tejto štúdii bol na analýzu vplyvu simulovaného odlesnenia na jednotlivé zložky vodnej bilancie použitý hydrologický model s distribuovanými parametrami. Výskum bol realizovaný v povodí Ulička na východnom Slovensku (97 km2, lesnatosť 84,3 %). Pri súčasnom využívaní krajiny pripadalo na intercepciu v priemere 21,1 % z celkového úhrnu zrážok počas kalibračného obdobia 2001 - 2013. Najväčší podiel zrážok (77 %) bol infiltrovaný do pôdneho profilu a necelá polovica z tohoto množstva prenikla do vodonosnej vrstvy podzemnej vody. Zatiaľ čo podpovrchový odtok tvoril z celkového úhrnu zrážok približne 12 %, v prípade povrchového odtoku išlo len o 1,2 % podiel. Najvyššia časť úhrnu zrážok prispela k tvorbe základného odtoku (23 %). Simulované odlesnenie povodia vyvolalo významný pokles intercepcie (o 76 %) a evapotranspirácie (o 12 %). Celkový, povrchový, podpovrchový a základný odtok zároveň vzrástli o 20,4; 38,8; 9,0 a 25,5 %. Denný prietok sa v priemere zvýšil o 20 %. Odlesnenie významne ovplyvnilo kulminačný prietok vyvolaný simulovanou extrémnou zrážkovou udalosťou s pravdepodobnosťou výskytu 100 rokov. V odlesnenom povodí bol kulminačný prietok o 58 % vyšší v porovnaní s prietokom pri súčasnom využití územia. Kulminačné prietoky sa vyskytli po 432 minútach od začatia zrážkovej udalosti pri súčasnom využití územia a po 378 minútach v prípade scenára odlesnenia. Prezentované výsledky poukázali na riziko nepriaznivého vplyvu rozsiahlych odlesnení na hydrologické procesy v povodí. Vyvinutý hydrologický model zároveň umožňuje testovanie vplyvu rôznych scenárov využívania krajiny, čím podporuje manažment lesa a krajiny v skúmanom povodí.

Inter- and intra-annual dynamics of height increment in young beech and spruce stands in relation to tree size and weather conditions

Abstract We investigated the seasonal dynamics of height increment, as well as total annual height increment, in 2009-2013 on young stands of beech and spruce grown at the same site. The results showed that the inter-annual dynamics of basic stand characteristics, especially tree density, were more obvious in spruce than in beech stands. Much higher tree mortality in spruce was explained by a lower light intensity under the spruce stand canopy and higher tolerance of beech to shade. Large interspecific differences were also found in the timing of height increment. Specifically, the height increment of beech trees started earlier than those of spruce. Moreover, the terminal grew for longer in spruce (nearly 70 days) compared to beech (about 45 days). The comparisons between the courses of the height increment and the ambient factors suggested that global radiation played a principal role. In the beech stand, the maximum height increment rate occurred during the same days as the maximal global radiation in 2009 and 2011, while a decline of the height increment occurred simultaneously with a depression in global radiation in 2012. As for the spruce stand, its one-peak maxima in height increment were related to the maximum of global radiation in 2009 and in 2012. On the other hand, double-peak courses of height increment in 2010 and 2011 may have been related to sudden declines in global radiation. Interspecific differences in height increment timing might play a certain role in cases of unfavourable weather conditions, e.g. drought episodes in the middle part of the growing season when the height increment would be accomplished in beech but would still be ongoing in spruce. Abstrakt Počas rokov 2009-2013 sme sledovali sezónnu dynamiku výškového prírastku, ako aj celoročný výškový prírastok v bukových a smrekových mladinách rastúcich na totožnom stanovišti. Výsledky naznačili, že medziročné zmeny základných porastových charakteristík, a to najmä hustota porastu, boli výraznejšie v smrečine než v bučine. Omnoho vyššia stromová mortalita v smrečine sa vysvetlila nižšou intenzitou svetla pod korunovou vrstvou smrekov, resp. vyššou toleranciou buka na zatienenie. Veľké medzidruhové rozdiely sa zaznamenali v „načasovaní“ výškového prírastku. Konkrétne výškový prírastok bukov začal každoročne skôr ako výškový prírastok smrekov. Ďalej, terminál smrekov rástol dlhšie (približne 70 dní) v porovnaní s bukmi (45 dní). Porovnanie priebehov výškových prírastkov vzhľadom na prostredie naznačilo, že principiálny vplyv mala globálna radiácia. V bučine bola maximálna intenzita výškového prírastku počas dní s maximálnou úrovňou globálnej radiácia, a to v rokoch 2009 a 2011, zároveň pokles intenzity sa objavil simultánne s poklesom globálnej radiácie počas roku 2012. V smrečine intenzita výškového prírastku predstavovala jednovrcholovú krivku - s najvyššou intenzitou prírastku v dňoch maximálnych hodnôt globálnej radiácie počas 2009 a 2012. Na druhej strane sa zaznamenal dvojvrcholový výskyt maxím intenzity výškového prírastku smrekov v 2010 a 2011. Tento jav súvisel s dočasným poklesom globálnej radiácie v týchto rokoch. Medzidruhové rozdiely v načasovaní výškového prírastku môžu mať relevanciu v prípade výskytu nepriaznivých poveternostných podmienok. Napríklad pri epizódach sucha v polovici vegetačného obdobia, keďže výškový prírastok je vtedy už ukončený pri bukoch avšak na smrekoch ešte prebieha

Identification of phytogeographical borders using grassland vegetation data

The paper proposes a methodology of phytogeographical regionalisation using grassland vegetation data. The research area is located in the West Carpathians, in volcanic field with adjacent post-tectonic basins and valleys in the Central Slovakia. The applied techniques were variogram modelling, ordinary kriging and lattice wombling. Phi coefficient was used to determine the diagnostic species of proposed phytochoria (fidelity test). The 1978 unevenly distributed grassland polygons that comprised 1071 taxa of vascular plants were the subject of the analyses. Ecological indicator values for temperature (EITs), weighted by species coverage in the Tansley scale in each grassland polygon, were used for the modelling. The gradients in the surface of the indicator value produced by ordinary kriging were analyzed. The steepest gradients indicate the most radical changes in floristic composition typical of border locations.The steepest gradient divides the study area into main cold and main warm regions. Less intensive gradients determined the position of 15 subdistricts. Subsequently, 7 out of 15 subdistricts were merged on the basis of similar natural conditions and floristic composition into 3 districts.Ten, mostly thermophilous, diagnostic species were determined for the main warm region. Fourteen, mostly psychrophilous, diagnostic species were determined for the main cold region. Subsequently, diagnostic species were determined for districts. High number of diagnostic species (57) characterize the Pol’ana Mts district. Eleven diagnostic species were determined for the Zvolenská kotlina basin district. The Javorie and Ostrôžy Mts district was very poorly diferentiated with 3 diagnostic species.Such evaluation suggests that proposed methodology allowed for the identification of phytochoria with specific floristic composition. The obtained results are discussed.

Climate Change Adaptation in the Carpathian Mountain Region

The Carpathian mountain region is one of the most significant natural refuges on the European continent. It is home to Europe’s most extensive tracts of montane forest, the largest remaining virgin forest and natural mountain beech-fir forest ecosystems. Adding to the biodiversity are semi-natural habitats such as hay meadows, which are the result of centuries of traditional land management. Like other mountain regions areas, the Carpathian mountain region provides important ecosystem goods and services such as water provision, food products, forest products and tourism. But these ecosystem services are feared to be under threat from climate change.