Ivan Barka

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.

The impact of Norway spruce planting on herb vegetation in the mountain beech forests on two bedrock types

Planting of spruce on the sites of natural beech forests is very common across Europe. Its effect on ground vegetation is assumed to be strong on poorly buffered soils. We investigate associated patterns of herb layer composition and diversity on crystalline and carbonate parent rock in the Western Carpathians. We analysed a series of vegetation plots with respect to the partial relationship of spruce cover with vascular understorey species (ordination), to the affinity of plant species to sample groups with different cover of spruce and to plant diversity and species turnover within these groups. In our data set spruce and beech were the most important tree species with the closest association with understorey composition and their covers explained similar proportions of herb layer variability. Species composition was significantly different under spruce canopies, but species richness was not lower (crystalline region) or even higher (carbonate region), and overall diversity of vascular plants was only slightly affected. Most species negatively or positively associated with spruce differed between bedrock types, but those with the same positive relationship are diagnostic for natural spruce forests (Vaccinio-Piceetea). The species turnover between beech- and spruce-dominated stands was much higher on crystalline bedrock. The higher amounts of light and acid litter in spruce stands, limited growth of spruce on dolomite bedrock and the competitive pressure of beech seem to be the most important drivers of the herb layer changes.

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.

Effect of different tree mortality patterns on stand development in the forest model SIBYLA

Abstract Forest mortality critically affects stand structure and the quality of ecosystem services provided by forests. Spruce bark beetle (Ips typographus) generates rather complex infestation and mortality patterns, and implementation of such patterns in forest models is challenging. We present here the procedure, which allows to simulate the bark beetle-related tree mortality in the forest dynamics model Sibyla. We explored how sensitive various production and stand structure indicators are to tree mortality patterns, which can be generated by bark beetles. We compared the simulation outputs for three unmanaged forest stands with 40, 70 and 100% proportion of spruce as affected by the disturbance-related mortality that occurred in a random pattern and in a patchy pattern. The used tree species and age class-specific mortality rates were derived from the disturbance-related mortality records from Slovakia. The proposed algorithm was developed in the SQLite using the Python language, and the algorithm allowed us to define the degree of spatial clustering of dead trees ranging from a random distribution to a completely clustered distribution; a number of trees that died in either mode is set to remain equal. We found significant differences between the long-term developments of the three investigated forest stands, but we found very little effect of the tested mortality modes on stand increment, tree species composition and diversity, and tree size diversity. Hence, our hypothesis that the different pattern of dead trees emergence should affect the competitive interactions between trees and regeneration, and thus affect selected productivity and stand structure indicators was not confirmed.

Assessment of the health condition of flood forests in the river Danube inundation area, section Dobrohošt - Sap using aerial photos

Zhodnotenie zdravotného stavu lužných lesov v inundačnej oblasti Dunaja v úseku Dobrohošť - Sap z leteckých snímok V práci zhodnocujeme zdravotný stav lužných lesov ovplyvnených prevádzkou vodného diela Gabčíkovo v inundácii Dunaja v úseku Dobrohošť - Sap z multispektrálnych leteckých snímok z roku 2008. Ďalej sumarizujeme výsledky z jednotlivých snímkovaní z rokov 1996, 1999, 2002 a 2005. Ako indikátory zdravotného stavu využívame defoliáciu a výskyt silne poškodených stromov a suchárov v porastoch. Na základe zhodnotenia oboch indikátorov konštatujeme, že realizovaním hydrotechnických úprav s prehrádzkovaním ramennej sústavy sú zabezpečené vhodné podmienky predovšetkým pre lužné lesné spoločenstvá prechodných a tvrdých luhov, ktoré plošne v záujmovom území dominujú a ktorých zdravotný stav dlhodobo hodnotíme ako veľmi dobrý. V 64 porastoch o celkovej výmere 334 ha sledujeme zvýšený výskyt suchárov. Najpostihnutejšie sú vekovo staršie spoločenstvá mäkkých luhov. Assessment of the health condition of flood forests in the river Danube inundation area, section Dobrohošt - Sap using aerial photos We assess in the paper the health condition of floodplain forests being affected by the operation of Gabčíkovo hydropower plant in the inundation area of the Danube River in the section Dobrohošt - Sap using multispectral aerial photos obtained in 2008. We summarize results from aerial photographing in the years 1996, 1999, 2002 and 2005. We use defoliation and occurrence of heavily damaged trees as well as snags in stands as indicators of the health condition of stands. Based on the assessment of both indicators we may state that by the construction of dam with artificial channel system there are secured suitable conditions, first of all, for floodplain forest communities of transitional type and hard floodplain forests, which dominate in the interest area what concerns the area they cover on this territory. We may assess their health condition as very good in a long term. We monitor increased occurrence of snags in 64 stands with total area 334 hectares. Soft floodplain forests of higher age are the most affected communities.