Modelling the potential distribution of three climate zonal tree species for present and future climate in Hungary = Három klímazonális fafaj hazai potenciális elterjedésének modellezése jelenlegi és jövőbeni klímában

The potential distribution and composition rate of beech, sessile oak and Turkey oak were investigated for present and future climates (2036–2065 and 2071–2100) in Hungary. Membership functions were defined using the current composition rate (percentage of cover in forest compartments) of the tree species and the long-term climate expressed by the Ellenberg quotient to model the present and future tree species distribution and composition rate. The simulation results using the regional climate model REMO showed significant decline of beech and sessile oak in Hungary during the 21st century. By the middle of the century only about 35% of the present beech and 75% of the sessile oak stands will remain above their current potential distribution limit. By the end of the century beech forests may almost disappear from Hungary and sessile oak will also be found only along the Southwest border and in higher mountain regions. On the contrary the present occurrences of Turkey oak will be almost entirely preserved during the century however its distribution area will shift to the current sessile oak habitats. | The potential distribution and composition rate of beech, sessile oak and Turkey oak were investigated for present and future climates (2036–2065 and 2071–2100) in Hungary. Membership functions were defined using the current composition rate (percentage of cover in forest compartments) of the tree species and the long-term climate expressed by the Ellenberg quotient to model the present and future tree species distribution and composition rate. The simulation results using the regional climate model REMO showed significant decline of beech and sessile oak in Hungary during the 21st century. By the middle of the century only about 35% of the present beech and 75% of the sessile oak stands will remain above their current potential distribution limit. By the end of the century beech forests may almost disappear from Hungary and sessile oak will also be found only along the Southwest border and in higher mountain regions. On the contrary the present occurrences of Turkey oak will be almost entirely preserved during the century however its distribution area will shift to the current sessile oak habitats

Accelerated Height Growth Versus Mortality of Quercus petraea (Matt.) Liebl. in Hungary

Background and Purpose: Due to climate change, it is important to know to what extent forests will be impacted by atmospheric changes. This study focuses on the height growth response of sessile oak (Quercus petraea (Matt.) Liebl.) to counteracting effects of fostering and interfering changes under contrasting climatic conditions with special attention to the xeric limit zone of this species. Materials and Methods: Twenty-eight sites were selected along a climatic gradient from the humid region in southwest Hungary to the continental-semiarid region in northeast Hungary where neighbouring old and young sessile oak stands were available for pair-wise comparison of height growth. While these young stands developed entirely in the significantly changed atmospheric conditions, the older trees lived only a part of their life time in such changed environment. The Ellenberg quotient (EQ) was used for describing climate aridity. Stand top height in each pair of old and young stands was measured to calculate the relative stand top height using yield tables of sessile oak for Hungary. Additionally, stand densities of old stands were measured. To demonstrate the height growth differences of old and young stands their relative stand top heights were compared as functions of EQ and stand density. Results: The relative top heights of the young stands were significantly higher than of the older stands, which means that the overall growing conditions were better in the last 30-35 years due to atmospheric changes than the mean conditions during the lifetime of old stands. Although extreme drought events associated with climate change caused reduced stand density due to periodic tree mortality at the xeric limit of sessile oak, the synergetic effect of all atmospheric changes was still sufficient enough to accelerate height growth. Conclusions: There has been an acceleration of height growth during the last decades despite the increased frequency of droughts. It cannot be concluded that height growth acceleration will continue in the future since climate models show an increasing tendency of dry extremes in Hungary that may overrule the positive fostering effect of atmospheric changes

The timing of leaf flush in European beech (Fagus sylvatica L.) saplings

Spring phenology is considered one of the most important determinants of growth and survival in young stands. It is relatively easy to monitor and is expected to respond to climate changes that will affect the favourable period for growth in temperate regions. The response of trees to the environmental cues that govern spring phenology is largely under genetic control and inter-populational differences exist within species. This suggests that the trait undergoes site-specific selection. Data obtained through monitoring of bud burst at multiple beech provenance-trials were compared with specific site and weather data to reveal geographical clines in beech phenology. We fitted the Weibull function to harmonise phenology data collected using various flushing scales and at different intensities of monitoring. By comparing data from 20 annual census of phenology performed across 13 sites throughout Europe, we showed that accumulated temperature sum > 5°C modelled the timing and duration of flushing more consistently than other temperature sum models > 0°C or > 8°C, or simply Julian Day. Inconsistency in the number of degree hours required for flushing among sites, reinforced the need for testing of more complex mechanistic models that include photoperiod, chilling period, and summer drought in addition to temperature sum. South-North, East-West, and low-high elevational clines were confirmed from the analysis. These findings; reinforce the need for caution in planting provenances from the south-east of Europe, suited to warmer-drier summers, in more north-westerly sites; and highlight the location of some potentially valuable late-flushing populations that also tolerate warm dry temperatures.Peer reviewe

Fapusztulás és gyorsuló növekedés kocsánytalan tölgyeseinkben

Hazánkban a klímaváltozással együtt járó aszályok évtizedek óta fapusztulásokat okoznak kocsánytalan tölgyesekben is. Másfelől több hazai publikáció született e fafaj növekedésének gyorsulásról, de lassulásáról is. Vizsgáltuk, hogy van-e növekedésgyorsulás a száraz klímájú kocsánytalan tölgyes termőhelyeken, ahol évtizedek óta számottevő a kigyérülés a középkorú és az idősebb állományokban. Eredményeink szerint száraz tájainkon is egyértelműen gyorsult a fiatal kocsánytalan tölgyesek magassági növekedése. Az évtizedek óta időszakonként fellépő fapusztulás, valamint ezzel szemben a magassági-növekedés gyorsulása mégsem ellentmondásos. A fentiekből nem következik, hogy a többlet növekedés a jövőben is jellemző lesz, mert a klíma előrejelző modellek szerint az aszálygyakoriság növekvő tendenciát fog mutatni

Knowledge gaps about mixed forests : What do European forest managers want to know and what answers can science provide?

Research into mixed-forests has increased substantially in the last decades but the extent to which the new knowledge generated meets practitioners' concerns and is adequately transmitted to them is unknown. Here we provide the current state of knowledge and future research directions with regards to 10 questions about mixed forest functioning and management identified and selected by a range of European forest managers during an extensive participatory process. The set of 10 questions were the highest ranked questions from an online prioritization exercise involving 168 managers from 22 different European countries. In general, the topics of major concern for forest managers coincided with the ones that are at the heart of most research projects. They covered important issues related to the management of mixed forests and the role of mixtures for the stability of forests faced with environmental changes and the provision of ecosystem services to society. Our analysis showed that the current scientific knowledge about these questions was rather variable and particularly low for those related to the management of mixed forests over time and the associated costs. We also found that whereas most research projects have sought to evaluate whether mixed forests are more stable or provide more goods and services than monocultures, there is still little information on the underlying mechanisms and trade-offs behind these effects. Similarly, we identified a lack of knowledge on the spatio-temporal scales at which the effects of mixtures on the resistance and adaptability to environmental changes are operating. Our analysis may help researchers to identify what knowledge needs to be better transferred and to better design future research initiatives meeting practitioner's concerns.Peer reviewe