Jiří Trombik

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.

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.

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.

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.

Large larch bark beetle Ips cembrae (Coleoptera: Curculionidae, Scolytinae) in the Czech Republic: analysis of population development and catches in pheromone traps / Lýkožrout modřínový Ips cembrae (Coleoptera: Curculionidae, Scolytinae) v České republice: analýza vývoje populací a vzorků z feromonových lapačů

Abstract The paper summarises available data on the occurrence of Ips cembrae in the Czech Republic and analyses the effect of temperature and precipitation on its population growth; compares numbers of beetles of overwintering and offspring generation, and compares the proportion of females and males caught in pheromone traps. The analysed data of the Forestry and Game Management Research Institute about the volume of harvested wood infested by I. cembrae from 1994 to 2013 varied between 150 and 1,415 m3. During the entire study period I. cembrae attacked more than 0.5 m3 per ha of larch forest stands in only four districts. Temperatures over the period from March to October, from April to June and annual average temperatures during the preceding and actual years, and the ratio of the annual rainfall to long-term rainfall average obtained from the Czech Hydrometeorological Institute had no significant effect on the population growth. Adults were also caught with pheromone traps, in which two generations were documented. In 2013, the numbers of caught beetles of the offspring generation exceeded those of the overwintering generation. This was due to warm and dry weather and, probably also due to high reproductive success. Although more females were caught by pheromone trapping, numbers of males and females did not differ significantly. During the studied period several periods of local outbreak of I. cembrae occurred in the Czech Republic, but their causes remained unclear, although the increase of bark beetles populations is generally regarded as a result of hot and dry weather. Larch bark beetle represents only a marginal problem in the Czech Republic. Abstrakt Práce shrnuje dostupná data o výskytu lýkožrouta modřínového Ips cembrae v České republice, analyzuje vliv teplot a srážek na jeho populační růst, srovnává početnost brouků přezimující (rodičovské) a dceřiné (letní) generace a porovnává podíl samic a samců ve feromonových lapačích. Byla analyzována dostupná data Výzkumného ústavu lesního hospodářství a myslivosti, v.v.i. o objemech vytěženého dříví napadeného I. cembrae z období let 1994-2013 v České republice, které varírovaly mezi 150 a 1 415 m3 a klimatická data Českého hydrometeorologického ústavu. V průběhu celého sledovaného období napadl l. modřínový pouze ve čtyřech okresech více než 0.5 m3/ha modřínových porostů. Teploty od března do října, teploty od dubna do června a průměrné roční teploty předchozích let i běžného roku a procento ročního úhrnu srážek k dlouhodobému průměru neměly statisticky signifikantní vliv na populační růst tohoto druhu kůrovce. L. modřínový byl také odchytáván deskovými lapači s feromonovými odparníky, přičemž byly pozorovány jeho dvě generace . V roce 2013 byl počet odchycených jedinců z letní (dceřiné) generace vyšší než z přezimující (rodičovské) generace. Pravděpodobně v důsledku horkého a suchého počasí a možná také vysokému reprodukčnímu úspěchu. Ačkoli bylo feromonovými lapači odchyceno více samic, počty odchycených samců a samic se signifikantně nelišily.Ve studovaném časovém období nastalo v České republice několik období lokálních gradací I. cembrae, příčiny jejich vzniku jsou nejasné, přestože je zvětšování populací lýkožroutů obecně považováno za důsledek teplého a suchého počasí, nepodařilo se doložit vliv teplot a srážek na populační růst. V České republice představuje l. modřínový pouze marginální problém.