Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2022
Authors
Lena Wohlgemuth Pasi Rautio Bernd Ahrends Alexander Russ Lars Vesterdal Peter Waldner Volkmar Timmermann Nadine Eickenscheidt Alfred Fürst Martin Greve Peter Roskams Anne Thimonier Manuel Nicolas Anna Kowalska Morten Ingerslev Päivi Merilä Sue Benham Carmen Iacoban Günter Hoch Christine Alewell Martin JiskraAbstract
Despite the importance of vegetation uptake of atmospheric gaseous elemental mercury (Hg(0)) within the global Hg cycle, little knowledge exists on the physiological, climatic, and geographic factors controlling stomatal uptake of atmospheric Hg(0) by tree foliage. We investigate controls on foliar stomatal Hg(0) uptake by combining Hg measurements of 3569 foliage samples across Europe with data on tree species' traits and environmental conditions. To account for foliar Hg accumulation over time, we normalized foliar Hg concentration over the foliar life period from the simulated start of the growing season to sample harvest. The most relevant parameter impacting daily foliar stomatal Hg uptake was tree functional group (deciduous versus coniferous trees). On average, we measured 3.2 times higher daily foliar stomatal Hg uptake rates in deciduous leaves than in coniferous needles of the same age. Across tree species, for foliage of beech and fir, and at two out of three forest plots with more than 20 samples, we found a significant (p<0.001) increase in foliar Hg values with respective leaf nitrogen concentrations. We therefore suggest that foliar stomatal Hg uptake is controlled by tree functional traits with uptake rates increasing from low to high nutrient content representing low to high physiological activity. For pine and spruce needles, we detected a significant linear decrease in daily foliar stomatal Hg uptake with the proportion of time during which water vapor pressure deficit (VPD) exceeded the species-specific threshold values of 1.2 and 3 kPa, respectively. The proportion of time within the growing season during which surface soil water content (ERA5-Land) in the region of forest plots was low correlated negatively with foliar Hg uptake rates of beech and pine. These findings suggest that stomatal uptake of atmospheric Hg(0) is inhibited under high VPD conditions and/or low soil water content due to the regulation of stomatal conductance to reduce water loss under dry conditions. Other parameters associated with forest sampling sites (latitude and altitude), sampled trees (average age and diameter at breast height), or regional satellite-observation-based transpiration product (Global Land Evaporation Amsterdam Model: GLEAM) did not significantly correlate with daily foliar Hg uptake rates. We conclude that tree physiological activity and stomatal response to VPD and soil water content should be implemented in a stomatal Hg model to assess future Hg cycling under different anthropogenic emission scenarios and global warming.
Abstract
No abstract has been registered
Authors
Mladen Ognjenovic Ivan Seletkovic Mia Marušic Mathieu Jonard Pasi Rautio Volkmar Timmermann Melita Percec Tadic Miran Lanšcak Damir Ugarkovic Nenad PotocicAbstract
No abstract has been registered
Abstract
In 2021, mean defoliation remained at approximately the same level as in 2020 with no change for broadleaves and only a very slight increase for conifers. Deciduous temperate oaks had the highest increase in mean defoliation (+1.4%), while common beech had the largest decrease (-1.7%). Based on the data of the past 20 years, trends show a considerable increase in defoliation of Austrian pine and evergreen oaks (7.1% and 6.7%, respectively). On the other hand, the increase in defoliation for deciduous temperate oaks (2.6%) and common beech (3.4%) has been relatively low and the trend for Scots pine and Norway spruce shows a moderate increase in defoliation of 4.3 and 3.8%, respectively. No trend was detected for deciduous (sub-) Mediterranean oaks. There was again a decrease in the number of observed damage symptoms compared to last year. As in previous years, the number of recorded damage symptoms per assessed tree was substantially higher for broadleaves than for conifers. Insects, abiotic causes, and fungi were the most common damage agent groups for all species, comprising altogether more than half of all damage records. Tree mortality increased again slightly in 2021, mainly due to abiotic factors.
Abstract
Bacterial diseases in woody plants are best characterized for ornamental and fruit trees and much less is known for forest trees. There are many diseases of forest trees whose etiology remains to be clarified and likely more bacterial diseases of forest trees will be discovered in the next years. An overview of the main bacterial pathogens that cause diseases in forest and ornamental trees is described in this chapter and the general differences between fungal and bacterial diseases are outlined. For bacteria pathogenic to trees, six types of diseases are described: Bacterial blight diseases, represented by Erwinia amylovora, the fireblight disease; Bacterial wilt disease, represented by Ralstonia solanacearum species complex; Root and stem galls of trees, represented by Agrobacterium tumefaciens; Wetwood disease, caused by several bacterial genera like Clostridium, Bacillus, Enterobacter, Klebsiella, and Pseudomonas, Xanthomonas and Pantoea; Bacterial scorch disease represented by Xylella fastidiosa with all its subspecies; Bacterial canker represented by Pseudomonas syringae with all its pathovars. Finally, the current diagnostic methods and specific issues related to bacteria detection, together with the main results of the scientific efforts and challenges in the genetic breeding to increase bacterial resistance of trees, are outlined.
Abstract
Pathogenic wood decay fungi such as species of Heterobasidion are some of the most serious forest pathogens in Europe, causing rot of tree boles and loss of growth, with estimated economic losses of eight hundred million euros per year. In conifers with low resinous heartwood such as species of Picea and Abies, these fungi are commonly confined to heartwood and thus external infection signs on the bark or foliage of trees are normally absent. Consequently, determining the extent of disease presence in a forest stand with field surveys is not practical for guiding forest management decisions such as optimal rotation time. Remote sensing technologies such as airborne laser scanning and aerial imagery are already used to reduce the reliance on fieldwork in forest inventories. This study aimed to use remote sensing to detect rot in spruce (Picea abies L. Karst.) forests in Norway. An airborne hyperspectral imager provided information for classifying the presence or absence of rot in a single-tree-based framework. Ground reference data showing the presence of rot were collected by harvest machine operators during the harvest of forest stands. Random forest and support vector machine algorithms were used to classify the presence and absence of rot. Results indicate a 64% overall classification accuracy for presence-absence classification of rot, although additional work remains to make the classifications usable for practical forest management.
Authors
Pingping Wang Marianne Stenrød Liang Wang Shankui Yuan Liangang Mao Lizhen Zhu Lan Zhang Yanning Zhang Hongyun Jiang Yongquan Zheng Xingang LiuAbstract
Atrazine is a widely used triazine herbicide, which poses a serious threat to human health and aquatic ecosystem. A montmorillonite–biochar composite (MMT/BC) was prepared for atrazine remediation. Biochar samples were characterized by using scanning electron microscope (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectrometer (XPS). Structural and morphological analysis of raw biochar (BC) and MMT/BC showed that MMT particles have been successfully coated on the surface of biochar. Sorption experiments in aqueous solution indicated that the MMT/BC has higher removal capacity of atrazine compared to BC (about 3.2 times). The sorption of atrazine on the MMT/BC was primarily controlled by both physisorption and chemisorption mechanisms. The amendment of MMT/BC increased the sorption capacity of soils and delayed the degradation of atrazine. Findings from this work indicate that the MMT/BC composite can effectively improve the sorption capacity of atrazine in aquatic environment and farmland soil and reduce the environmental risk.
Abstract
No abstract has been registered
Editors
Camilla BaumannAbstract
No abstract has been registered
Authors
Aritz Royo-Esnal Andrea Onofri Alireza Taab Donato Loddo Jevgenija Necajeva Ahmet Uludag Agnieszka Synowiec Isabel M. Calha Lars Andersson Peter K. Jensen Ilhan Uremis Garifalia Economou Alistair J. Murdoch Kirsten TørresenAbstract
The variability in the emergence process of different populations was confirmed for two Echinochloa crus-galli populations, one from Italy (IT) and the second from Norway (NO). Seeds were sown in 12 localities over Europe and the Middle East, and the emergence patterns of IT and NO were compared with those of several local populations at each location. Seeds of each population were sown in pots buried to the ground level. The base temperature (Tb) for emergence was estimated by (1) analysing logistic models applied to the field emergence of IT and NO, and (2) a germination assay set in winter 2020 at constant temperatures (8, 11, 14, 17, 20, 26, 29°C) with newly collected seeds in 2019 from the same fields where IT and NO had previously been harvested in 2015. The logistic models developed for IT and NO in each location showed that the emergence pattern of IT was similar to that of the local populations in Poland, Italy, Spain, Turkey South and Iran, while NO fitted better to those in Sweden and Latvia. No germination was obtained for IT in a germination chamber, but the estimated Tb with the logistic model was 11.2°C. For NO, the estimated Tb was 8.8°C in the germination chamber and 8.1°C in the field. Results suggest that adaptation to local environmental conditions has led to inter-population differences in Tb and parameter estimates of thermal-time models to predict the emergence of E. crus-galli should only be used for populations with similar climatic and habitat conditions.