Health status analysis of Norway spruce and shrubby pine along an elevation gradient

The results of numerous climatic models predict a significant increase in temperature, which coupled with other factors could affect mountain species distribution and community composition. In addition, it can accelerate an upward shift of alpine treelines. However the number of field measurements focusing on the health status of dominant trees in temperate mountains are limited. Our measurements were carried out in the Stuhleck Mountains along an elevation gradient from 850 to 1750 metres. Health status analysis of Picea abies and Pinus mugo have been completed by using FAKOPP 3D acoustic tomography, which is able to detect the size and location of decayed regions in the trunk non-destructively. For modelling the relationship between the decay of tree and other factors simple linear regression models were used. The results showed that the individuals of Picea abies and Pinus mugo had the worst health status in the lowest and uppermost range of the taxa in the studied area. It could be a sign of the upward shift of their range. Positive significant correlation was found between the decay and the ratio of whole trunk/healthy wood both in case of Picea abies and Pinus mugo. It seems, that acoustic tomography measurements are adequate to indicate non-destructively the altitudinal optimum and upward shift of different taxa

Optimizing conditions for sporulation of European mistletoe hyperparasitic fungus (Phaeobotryosphaeria visci): effect of light and different media

Volume: 50 Host publication title: 6th International Plant Protection Symposium at University of Debrecen Proceeding volume: 50European mistletoe (Viscum album), the hemiparasitic shrub, infects a wide range of woody species. It adversely affects the height and diameter growth and it is associated with increased mortality of its hosts. Currently there are no effective control methods against it. Therefor, we started to study a specific hyperparasitic fungus (Phaeobotryosphaeria visci), which can completely destroy European mistletoe by infecting its branches, leaves and berries. An important aspect of the initial phase of mycopesticide candidate is culturing of the organism on artificial or non-synthetic media, followed by the optimization of spore production. We focused to determinate the growth media and light conditions needed for sporulation of P. visci. We also tested the viability and pathogenecy of the spores, because these are important features for further processing and applications. The cultures were grown on seven different media (potato dextrose agar, sugar free potato dextrose agar, cellophane covered potato dextrose agar, oatmeal agar, V8 Juice agar, S medium and SNA medium) under constant dark, constant light (400-750 nm) and 12 h of alternating dark and light illumination. The best primary agar media were oatmeal and sugar free potato dextrose agar under permanent illumination, while constant dark inhibited the conidial production. The viability and virulence of harvested conidia were normal, and the symptoms of the disease appeared 7-14 days after the inoculation on mistletoe leaves. We will continue our experiments studying the effect of near UV (280–400 nm) light. Use of variable photoperiods supplemented with near UV and different media could help us to optimize the spore production and create a fast and cheap mass production technique.Peer reviewe

Examining the Stand Level CO2 Fluxes of Spring Forest Geophytes

Spring forest ephemerals often create homogeneous patches in the understory; however, our knowledge about their stand level characteristics is deficient. Our aims were to examine, parallel to their phenology, the stand level Net Ecosystem CO2 Exchange (NEE) and evapotranspiration (ET) fluxes as well as the dependence of NEE on leaf area (LA), air temperature (Tair) and light (PPFD) in three spring forest geophytes that are widespread in Europe. Furthermore, we compared the leaf and stand level net photosynthesis. The methods used included open chamber measurements with an infrared gas analyser in permanent plots on a weekly basis. The results showed that the stand levels of all three species proved to be carbon sinks from the beginning of the vegetation period until the end of it or until the last phase of fruit formation. The largest amount of carbon sink was observed at the peak of blooming. A positive linear correlation was measured between NEE and PPFD as well as between NEE and LA, while a negative linear regression was measured between NEE and Tair. The remarkable carbon uptake capacity indicates the non-negligible role of geophyte vegetation in the carbon flux of temperate forests. In addition, the research provided new proof about the role of stand level operation, stability and regulation.O

Comparative Study of the Phenology of Seven Native Deciduous Tree Species in Two Different Mesoclimatic Areas in the Carpathian Basin

The impact of global warming on plant phenology is the subject of a growing number of studies. However, most of these do not focus on woody species, and few examine the entire annual phenological cycle of woody species. In this paper, we explore the phenological pattern of seven woody species native to Europe under ex situ conditions for 3 years, in two urban areas with different mesoclimates. The average temperature differs by 1.81 oC between the two sites. The investigated plants were clonally identical for each species, and the exact same care protocol was kept at both sites. Despite the large variation in the phenological pattern between years, during the study, spring phenophases occurred earlier, while the examined autumn phenophases were delayed at the site observing a higher average temperature. The phenological sensitivity of flowering was significantly higher than that of leaf bud burst. The growing season was 14.8 days longer at the site with a higher average temperature. In most cases, a significant correlation was obtained between the examined phenophases and climatic factors at both sites. Among the autumn phenophases, the strongest correlation was found between the maximum temperature between July and October and the beginning of leaf coloring.O

Különböző szisztémikus herbicidek fehér fagyöngy (Viscum album) elleni hatékonyságának, illetve a fagyöngy hiperparazita kórokozójára gyakorolt antifungisztatikus hatásának vizsgálata

There are more than 3000 ha in Hungary infected by European mistletoe (Viscum album L.), which have currently raised. The only way to control this hemiparasite is to cut down the infected branches, while other effective control methods are unknown. Our research focused on the efficiency of herbicide control methods against V. album. We tested three herbicide agents and combinations in three concentrations during our study (glyphosate isopropylamine salt, 2,4-dichlorophenoxyacetic acid, methsulphuron-methil). After the pesticide treatments the phototoxic effects were studied on mistletoe shrubs and on the host trees (Acer campestre L.) too. The most efficient agent was 2,4-dichlorophenoxyacetic acid, which caused the whole necrosis of mistletoe shrubs even in the lowest concentration, but low chlorosis, rarification of foliage and drying of twigs were detected on the host trees. Phaeobotriosphaeria visci, which seems suitable for biological control, appeared 3–6 months after the application of 2,4-D on the necrotic mistletoe shrubs. Therefore the effect of 2,4-D and glyphosate on the mycelial growth were examined under in vitro laboratory conditions. Even the lowest herbicide concentration caused significantly lower mycelial growth; besides higher concentrations no mycelial growth was detected. An incidental combined herbicide and spore suspension treatment is not possible, due to the antifungal effects of these pesticides.Peer reviewe