Forest In Hungary Research Articles

The impact of ungulate browsing on black locust competitive abilities in a temperate oak forest

Invasive species such as black locust (Robinia pseudoacacia) cause several problems in conserving semi-natural forests in Europe. The selective browsing of ungulates can be a prominent regulating factor in the spread of black locusts. We set out a 4 year-long experiment in a fenced area of a Turkey oak (Quercus cerris) – sessile oak (Quercus petraea) forest in Hungary to 1) evaluate short-term responses of black locust saplings to simulated browsing; 2) identify the effects of browsing and soil conditions on the competition between black locust and oak saplings. We hypothesized that clipping treatments would reduce the growth and vitality of black locusts and indirectly enhance oak sapling development. Vegetation patches were designated to separate oak saplings with treated and intact black locust saplings, and without black locust. After the first round of treatments in September 2014, clipped black locusts compensated for height and shoot loss. The summer drought in 2015 reduced the survival of black locusts independently of the clipping and many saplings disappeared from previously occupied plots. In addition, the effects of the second clipping treatment in September 2015 have significantly slowed down, even hindering further growth of the clipped saplings. Soil nitrogen level was not higher in black locust plots, but low pH and significant soil compaction could be limiting factors for all saplings. Our results did not confirm any significant inhibitory effect of black locust on oak sapling development, but sessile oak had increased height growth compared to Turkey oak in black locust plots. It seems that browsing is only a secondary factor that influences the growth and competitiveness of black locusts since only repeated browsing after a heavy drought period could prevent black locust saplings from compensating for their losses.

Seamlessly combined historical and projected daily meteorological datasets for impact studies in Central Europe: The FORESEE v4.0 and the FORESEE-HUN v1.0

The FORESEE is an open access, climatological database for Central Europe containing observed and projected meteorological data for the 1951–2100 period. As a climate service, FORESEE disseminates basic meteorological variables at a daily time step with a 0.1° × 0.1° spatial resolution including maximum/minimum temperature, precipitation, incoming shortwave solar radiation and daylight vapour pressure deficit. The future climate in FORESEE v4.0 and FORESEE-HUN v1.0 is projected by 14 regional climate models from the EURO-CORDEX database using the Representative Concentration Pathways (RCP) 4.5 and 8.5 scenarios. Based on RCP4.5 the country-specific results indicate similar projected mean changes in annual mean temperature (1.5–1.7 °C) but considerable differences in precipitation (from −1.6 to 6.9%) in the region for 2071–2100 relative to 1991–2020. We present two case studies to demonstrate the applicability of FORESEE in climate change impact studies using the ensemble approach. Climate change induced negative weather effect (15.4% and 28.9% mean loss for 2071–2100 according to RCP4.5 and RCP8.5, respectively) might dominate the future winter wheat yields in Hungary that is superimposed to the overall trend determined by other factors. The projections provide consistent results about the mean advance in the start of the growing season for forests in Hungary up to 2100 with ensemble mean of 9.1 days (RCP4.5) and 19.8 days (RCP8.5). We also demonstrate that the representative model selection method might lead to misleading results in impact studies that should be considered. The updated FORESEE is a way forward in the dissemination of policy-relevant essential climate data in Central Europe.

The role of price incentives in enhancing carbon sequestration in the forestry sector of Hungary

This paper investigates the carbon sequestration potential of forests in Hungary through the introduction of a carbon price incentive, assuming an integrative national climate policy. We have developed a bio-economic mathematical optimisation model to represent the area and species distribution of Hungarian forests and we are optimising harvesting cycles without and with carbon payments. We assess the cost and volume of potentially available carbon removal by forests in the context of the national climate policy. To align our results with other climate policy instruments, we integrate the estimated carbon removal potential of the forests with the marginal carbon abatement cost curve of the energy sector in Hungary. We find that enhanced forest carbon sequestration can be more cost-effective than most other climate policy instruments. We find that forests could intervene at the lower end of the combined cost curve and shift it significantly to the right, resulting in much lower marginal and total costs of achieving the net zero target for Hungary.

Qualitative and Quantitative Changes in Soil Organic Compounds in Central European Oak Forests with Different Annual Average Precipitation

The various climate scenarios consistently predict warming and drying of forests in Hungary. Soils play a significant role in the long-term sequestration of atmospheric CO2, while in other cases they can also become net carbon emitters. Therefore, it is important to know what can be expected regarding future changes in the carbon storage capacity of soils in forests. We used precipitation gradient studies to solve this problem, using a type of “space–time” substitution. In this research, we primarily examined the quality parameters of soil organic matter (SOM) to investigate how climate change transforms the ratio of the main SOM compound groups in soils. For our studies, we applied elemental and 13C and 15N isotopic ratio analysis, NMR analysis, FT-IR spectra analysis, thermogravimetric and differential thermal analyses to measure SOM chemistry in samples from different oak forests with contrasting mean annual precipitation from Central Europe. Our results showed that soil organic carbon (SOC) was lower in soils of humid forests due to the enhanced decomposition processes and the leaching of Ca, which stabilizes SOM; however, in particular, the amount of easily degradable SOM compounds (e.g., thermolabile SOM, O-alkyl carbon, carboxylic and carbonyl carbon) decreased. In dry forest soils, the amount of recalcitrant SOM (e.g., thermostable SOM, alkyl carbon, aromatic and phenolic carbon and organo–mineral complexes stabilized by Ca increased, but the amount of easily degradable SOM increased further. The main conclusion of our study is that SOC can increase in forests that become drier, compensating somewhat for the decrease in forest plant biomass.

A matter of size and shape: Microclimatic changes induced by experimental gap openings in a sessile oak–hornbeam forest

Forest management integrating nature conservation aspects into timber production focuses increasingly on small-scale interventions. However, the ecological consequences of gap cuttings remain ambiguous in oak-dominated forests. In the Pilis Gap Experiment, we analyze how combinations of different gap shapes (circular and elongated), and gap sizes (150 m2 and 300 m2) affect the microclimate and biota of a mature sessile oak-hornbeam forest in Hungary. We first report the changes in direct and diffuse light, soil moisture, daily air and soil temperatures, and relative air humidity in the experimental cuttings in the vegetation season directly following their implementation. Diffuse light had a central maximum and a concentric pattern. Direct light was distributed along a north-south gradient, with maxima in northern gap parts. Soil moisture was determined by gap shape: it increased significantly in the center of circular gaps, with multiple local maxima in the southern-central parts of large circular gaps. Its pattern was negatively related to direct light, and larger spatial variability was present in circular than in elongated gaps. The daily mean air temperatures at 1.3 m increased in all, especially in large gaps. Soil and ground-level temperatures remained largely unchanged, reflecting on light and soil moisture conditions affecting evaporative cooling. Relative humidity remained unaltered. Even though the opening of experimental gaps changed microclimatic conditions immediately, effect sizes remained moderate. Gap size and gap shape were both important determinants of microclimate responses: gap size markedly affected irradiation increase, gap shape determined soil moisture surplus, while soil and air temperatures, and air humidity depended on both components of the gap design. We conclude that 150–300 m2 sized management-created gaps can essentially maintain forest microclimate while theoretically providing enough light for oak regeneration; and that the manipulation of gap shape and gap size within this range are effective tools of adaptive management.

Low understory condition in an oak forest in Hungary, 1972 and 2022 – Síkfőkút Project is 50 years old

erious oak decline was first detected in 1979-80 in a mixed sessile oak–Turkey oak forest (Quercetum petraeae-cerridis Soó 1963). This decline resulted important structural changes in the understory shrub layer. Despite of this, relatively few studies deal with shrub communities and shrub layer dynamics after oak death. The goals of this research were to determine the conditions of low shrubs and analyse the possible changes in this layer after 5 decades from the beginning of Síkfőkút research. Specimens which were lower than 1.0 m in height were categorized as low shrubs in the shrub community. In 1972 and in 2022, 16- 17 native low shrub species were observed in the understory; 15 species were present continuously in the forest. The density of low shrubs was 87401 and 17317 specimen ha-1. The most common low shrub species was Ligustrum vulgare and 5 decades later Quercus petraea with 24.1% and 37.8% ratio. The mean height and mean diameter of low shrub species changed among 10.3-67.0 cm and 1.5-7.5 mm. The mean cover of these shrubs fluctuated between 35 cm2 and 2026 cm2 based on the two measured year. Our results suggest that the low shrub layer responded negatively to the biotic and abiotic factors under 5 decades; this is especially true to the density, cover and diversity indices of species.

Effect of Different Irrigation Regimes on the Early Development of Pot-Grown Black Locust Saplings

Black locust currently is considered to be the most important tree species of short-rotation forests in Hungary with the purpose of either woody biomass or industrial wood. Despite the general supposition on the drought tolerance of the species, water availability seems to be a more limiting factor to exploit the growing potential of highly productive new varieties than nutrient amendments. Preliminary measurements of the current study were made on the connection between the depth of the water-retaining soil layer and the growth of saplings on black locust plantations. A significant negative correlation was found between the depth of the water-retaining layer, the stem diameter and the height of the saplings. To investigate the phenomenon, a model experiment was launched with loamy sand soil in the pots. During six weeks, pots were watered every morning up to the weight referring to the 30, 40, 60 and 80% of field capacity (FC). Our results showed that 30% FC was only sufficient for the survival of the saplings, growth was only noticeable at plants with 40% FC or more. During the first 4 weeks, differences in growth and cumulative evapotranspiration between the 60% and 80% FC treatment were not considerable. However, in the last two weeks, saplings with the highest FC produced substantially higher biomass, resulting in a one-third higher final weight than those of FC 60%. Even with the limited soil capacity of the pots, water use of these saplings of 1 m height and 1 cm stem diameter exceeded 1.5 L per day. Our results confirmed that black locust is a water-intensive species with a high water use potential, which emphasizes the importance of irrigation on nurseries and the first years of plantations.

Most important structural changes in a shrub community of deciduous oak forest in Hungary

Most important structural changes in a shrub community of deciduous oak forest in Hungary

No Long-Term Decrease in Caterpillar Availability for Invertivorous Birds in Deciduous Forests in Hungary

Numerous recent studies report an alarming decrease in diversity, biomass, or abundance of arthropods in various habitats. Given that they are important food for other organisms, the ecological consequences of such a decline could be severe. We used data from the Hungarian Forestry Light Trap Network to examine whether the spring caterpillar biomass showed any long term (23–58 years) declining trend in oak-dominated forests. Light trap data for 43 selected macrolepidopteran species (suitable bird food in the larval stage) from six different locations were used for the estimation of the total available caterpillar biomass. Time series analyses showed strong year-to-year fluctuations, and over all locations and time windows there was an increasing rather than decreasing trend. The increase found at some locations may suggest increasing herbivore pressure and negative impacts on forest health. We conclude that foliage-feeding macrolepidopteran species with spring-developing larvae did not show a drastic decrease in recent decades, and food availability in the long term will not negatively influence the breeding success of birds in such forests.

Woodpecker foraging activity in oak-dominated hill forests in Hungary

Abstract We documented the foraging activities of woodpeckers on selected trees in an established conservation-oriented management study in five oak-dominated forests in Hungary. We examined the tree species preference of woodpeckers as a group and the impact of specific tree characteristics on the habitat use of woodpeckers. We estimated the percentage of visible foraging signs on the trunks and upper limbs of selected trees through the winter and early spring of 2019–2020. Based on the Jacobs’ index, woodpeckers preferred oak species for foraging and most foraging signs were on limbs rather than trunks. Foraging signs on trunks were more frequent on those of larger diameters and greater heights. It was also found that the lower the tree, the greater the effect of its diameter on the occurrence of signs.

Individual movement of large carabids as a link for activity density patterns in various forestry treatments

Activity density is one of the most common measures for ground-dwelling arthropods including carabids. The term refers to the empirical fact that pitfall trap catches depend on the individuals’ activity; the higher activity of the individuals, the more catches in the traps. Although the movement at the individual level is widely studied, there is no available evidence whether the individual movement can be a good proxy for activity density. In our study, we aimed to explore this link in two ground beetle species, Carabus scheidleri and C. coriaceus, in oak-hornbeam forest in Hungary. We used pitfall traps for activity density and capture-mark-recapture and radio telemetry to record individual movement patterns in different forestry treatments, preparation cuttings and clear-cuttings, and their control plots. We identified an indirect link between activity density and movement of individuals via treatment types. Although activity density, mean walking speed, and the proportion of active time were significantly higher in both treatments than in control plots, individual movement reveals only temporal use of these habitats. Beetles left treatments within a few days. We concluded that the high turnover of individuals in treatments might indirectly suggest that these habitats likely act as temporary foraging sites for both species.

Effects of Meteorological and Site Parameters on the Health Status of Beech (Fagus sylvatica L.) Forests in Hungary

The influence of meteorological parameters on the health status of beech (Fagus sylvatica L.) was analyzed using long term datasets (1989-2010) collected in 15 sample plots located in Hungary’s main beech regions. Leaf loss values were correlated with different meteorological parameters as explanatory variables. Analysis was performed by the CReMIT (Cyclic Reverse Moving Intervals Techniques) method. Weather, stand, and site parameters were also examined with PCA for comparison. Leaf loss levels showed stronger correlations with maximum monthly temperatures than with monthly precipitation sums. The monthly number of summer days and monthly number of hot days displayed a similar correlation to leaf loss as the maximum monthly temperature did. The correlations were regularly stronger and more frequent on more arid sites where the climate is less favorable for beech. Temperature affected leaf loss more than precipitation did. Our results show that beech forests may suffer heavy damage if climate change continues as projected.

Green tree retention enhances negative short-term effects of clear-cutting on enchytraeid assemblages in a temperate forest

We studied the response of enchytraeid (Annelida: Oligochaeta) community structure to different forest management treatments via an open-field forestry experiment in a managed sessile oak-hornbeam forest in Hungary. The applied forestry treatments were 1) clear-cutting 2) clear cutting with a small patch of retention tree group, 3) gap-cutting, 4) preparation cutting and 5) control (closed mature stand).Our questions were: how did the selected forestry treatments influence the abundance and species richness of enchytraeids two years after the intervention, and how could the worms compensate the altered environmental conditions by vertical movements in topsoil layers (0–12 cm). The effects of the treatments on the species composition of the assemblages and species-specific responses were also analysed.Two years after the treatments, a strong response of enchytraeids was observed in clear-cutting and even more in retention tree group: in both treatments the abundance and the species richness of enchytraeids were reduced. Species did not show vertical movements into deeper layers and were not able to tolerate the altered soil conditions caused by changed microclimate. Gap-cutting and preparation cutting did not differ significantly from control plots. Our study showed that right after the interventions tree retention at the size of one tree height in diameter had no sheltering effect on this important soil decomposer animal community. These results are in contrast with earlier findings in boreal zones, where soil organic layer is considered a well buffered habitat against environmental changes. Oppositely, enchytraeid assemblages in a temperate deciduous forest are more diverse but seem more vulnerable to management-related alterations in soil conditions (soil temperate increment, reduced soil moisture).

Kinetic parameters of soil organic matter decomposition in soils under forest in Hungary

To obtain better knowledge on how soil organic matter (SOM) decomposition is regulated by different soil properties, 13 soil samples amended with maize residues were incubated for 163 days. Carbon mineralization kinetics was modelled by fitting five different kinetic models, from which the first-order two pools model was selected for further analysis. The results showed that residue addition increased the rate of C mineralization, particularly in sand samples, where four times as much C was released as CO2 in amended samples as in control samples. Residue addition also affected the kinetic parameters of the two C pools modelled. The mean residence time (MRT) averaged 31.9 days for the fast C pool and 65.1 days for the slow C pool phase in the amended soils, whereas in the control soils MRT1 and MRT2 averaged 52.3 and 94.2 days, respectively. The kinetics of C decomposition was found to be influenced to the greatest extent by soil organic carbon (SOC) content and soil texture. The texture primarily affected the size of the fast carbon pool (C1): in both the amended and control samples C1 was increased by the clay content (r = 0.574 and r = 0.554, respectively) and decreased by the sand content (r = −0.771 and r = −0.583, respectively). Our results confirm the fact that texture has a significant role in soil organic matter mineralization, however other parameters also play a crucial role in the decomposition due to the complexity of the processes.

A novel forest state assessment methodology to support conservation and forest management planning

A new forest state assessment methodology to complement existing conservation and forestry data has been developed. The aim is to provide tools for strategic planning including spatial distribution of conservation priorities. The method is point-based using a dense systematic sampling grid and provides more detailed information than vegetation maps or forest subcompartment descriptions, but requires less effort than forest inventories. Indicators include canopy composition and structure, deadwood, herbs, microhabitats, disturbances, shrubs and regeneration. The results can inform managers about the structural and compositional diversity of forest stands in the form of thematic maps and can provide the basis for analysis of habitat suitability for forest-dwelling organisms. A smartphone application has been developed to enable electronic data collection. PostGIS and Python scripts were used in the data flow. In this paper, we outline the development of the assessment protocol, and present the sampling design and the variables recorded. The main advantages of the survey methodology are also shown by case-studies based on data collected during the first field season in 2014. The protocol has been designed for low mountain forests in Hungary, but it can be modified to fit other forest types.

Nonlinear height–diameter models for three woody, understory species in a temperate oak forest in Hungary

Information about the diameter and the height of woody species is fundamental to developing growth and yield models in forest stands. Ten nonlinear height–diameter functions were fitted and evaluat...

Environmental drivers of the composition and diversity of the herb layer in mixed temperate forests in Hungary

Herbaceous understory vegetation is an important part of temperate forested ecosystems, the diversity and composition of which are strongly dependent on the conditions of the forest stand and the landscape. The aim of this study was to find the most important environmental drivers influencing understory herb layer species composition (explored with multivariate analysis), and richness and cover (analysed by linear modelling) in managed mixed forests in West Hungary. Our detailed inventory showed that the most important factors increasing the diversity and cover of the understory are light, tree species richness, and landscape diversity. Composition is also mainly influenced by light conditions and tree species richness, with minor effects of tree species composition, soil texture, and moss cover. As the strongest influencing factors are closely linked to stand structure and tree species composition, they can either directly or indirectly be altered by forest management. In the studied region, heterogeneous light conditions and canopy structure, the maintenance of tree species richness and forest continuity are key elements for the conservation of forest herbs. Forestry that maintains continuous forest cover and the tree selection management system can better provide these conditions than the presently widely used shelterwood management system.

Short-term changes in height–diameter relation of two maple species and European cornel of understory in an oak forest in Hungary on the basis of two-parameters model

Forest understory species such as shrub and herbaceous layer, have received little attention in long-term studies. Knowledge of the diameter and the height of trees are fundamental for developing growth and yield models in forest stands. Overstory composition of the Sikfőkut Project site was dominated by sessile oak–Turkey-oak forest (Quercetum petraeae-cerris Soo 1963). Similarly to other European countries an oak decline occurred in Hungary oak woodlands at the end of 1970’s and about 63% of the oak trees perished in our site. The potential for oak species regeneration was a very low over the period of 1982-2012. Four nonlinear height-diameter functions were fitted and evaluated for Sikfőkut site based on a data set consisting of 2025 individuals for three dominant woody species (Acer campestre L., Acer tataricum L. and Cornus mas L.) and detected any short-term changes in these equations following dieback of oak canopies. These height– diameter equations increase our knowledge of the growth of these species; therefore will enable us to improve management planning in oak forests.

The effect of the invasive Asclepias syriaca on the ground-dwelling arthropod fauna

AbstractThe management of natural and seminatural systems often leads to disturbance associated with the appearance of non-native species. The spread of these species is increasing due to global environmental changes combined with local management interventions. These non-native species may establish self-sustaining populations influencing ecosystem functions, including the habitat use of native species. Here we explore the response of diplopods, spider and ant assemblages and the activity-density of individual species to the establishment of the non-native plant species, Asclepias syriaca in a disturbed poplar forest in Hungary. The relationship between the species richness of spiders and ants and the structural features of A. syriaca was weak. We found a significant relationship between the structural features of A. syriaca stands and the density and activity of the diplopod Megaphyllum unilineatum. We explain this relationship by the modified microclimate and litter quality of the habitats invaded by A. syriaca. The species composition of ant and spider assemblages was sensitive to A. syriaca. Asclepias syriaca had a negative local effect on the abundance of two spider species which were common in the studied forest. However, A. syriaca positively influenced the abundance of two ant species, most probably via indirect trophic relationships, as they feed on aphids living on A. syriaca. Our study shows that invasive plants can have mixed effects on local invertebrate assemblages. It is therefore crucial to understand how native assemblages respond to these changes in order to better manage these novel ecosystems and maximize their biodiversity benefits.

Dehydrogenase Activity in a Litter Manipulation Experiment in Temperate Forest Soil

Abstract Soil enzyme activities are “sensors” of soil organic matter (SOM) decomposition since they integrate information about microbial status and physico-chemical condition of soils. We measured dehydrogenase enzyme activity in a deciduous temperate oak forest in Hungary under litter manipulation treatments. The Síkfőkút Detritus Input and Removal Treatments (DIRT) Project includes treatments with doubling of leaf litter and woody debris inputs as well as removal of leaf litter and trenching to prevent root inputs. We hypothesized that increased detrital inputs increase labile carbon substrates to soils and would increase enzyme activities particularly that of dehydrogenase, which has been used as an indicator of soil microbial activity. We also hypothesized that enzyme activities would decrease with detritus removal plots and decrease labile carbon inputs to soil. After ten years of treatments, litter removal had a stronger effect on soil dehydrogenase activity than did litter additions. These results showed that in this forest ecosystem the changed litter production affected soil microbial activity: reduced litter production decreased the soil dehydrogenase activity; increased litter production had no significant effect on the enzyme activity.