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    Spatial Distribution of Mucilage in the Rhizosphere Measured With Infrared Spectroscopy 

    Holz, Maire; Leue, Martin; Ahmed, Mutez A.; Benard, Pascal; Gerke, Horst H.; Carminati, Andrea
    Frontiers in Environmental Science 2018; 6: Art. 87
    Mucilage is receiving increasing attention because of its putative effects on plant growth, but so far no method is available to measure its spatial distribution in the rhizosphere.We tested whether the C-H signal related to mucilage fatty acids is detectable by infrared spectroscopy and if this method can be used to determine the spatial distribution of mucilage in the rhizosphere. Maize plants were grown in rhizoboxes filled with soil free of organic matter. Infrared measurements were carried out along transects perpendicular as well as axially to the root channels. The perpendicular gradients of the C-H proportions showed a decrease of C-H with increasing distance: 0.8mm apart from the root center the C-H signals achieved a level near zero. The measured concentrations of mucilage were comparable with results obtained in previous studies, which encourages the use of infrared spectroscopy to quantitatively image mucilage in the rhizosphere.
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    Mixed-species versus monocultures in plantation forestry: Development, benefits, ecosystem services and perspectives for the future 

    Liu, Corsa Lok Ching; Kuchma, Oleksandra; Krutovsky, Konstantin V.
    Global Ecology and Conservation 2018; 15
    Plantation forests are increasing rapidly in the world in order to alleviate deforestation and degradation of natural forests, along with providing various goods and services. While monoculture plantations have been the dominant type of plantation in practice and well-recorded in research, in the face of intensifying climate change and resource scarcity, there is a growing interest in mixed-species plantations. Agroforestry systems are also catching the attention of foresters, smallholders and landowners. However, there are relatively limited number of studies on successful species mixtures. This paper first reviews the progression of monocultures and mixed-species, followed by the comparisons of advantages, disadvantages and effects on the surrounding natural ecosystems between these two types of plantations. The paper further investigates combinations of species with complementary traits for efficient use of limiting resources associated with improvement in growth development and production of tree species, as well as examining some other challenges in mixed-species. In addition, it is helpful to select and combine tree/crop species in mixtures based on complementary traits that maximise positive and minimise negative interactions and using the advance molecular technologies for genetic analysis. With careful design and proper management, mixed-species plantations with two, three or four species can be more productive and have more advantages in biodiversity, economy and forest health over monocultures. Many researchers are still working on different projects to explore the potential benefits and to promote the applications of mixed-species plantations and agroforestry.
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    Tree Water Use Patterns as Influenced by Phenology in a Dry Forest of Southern Ecuador 

    Butz, Philipp; Hölscher, Dirk; Cueva, Eduardo; Graefe, Sophie
    Frontiers in Plant Science 2018; 9: Art. 945
    Tropical dry forests are composed of tree species with different drought coping strategies and encompass heterogeneous site conditions. Actual water use will be controlled by soil moisture availability. In a premontane dry forest of southern Ecuador, tree water use patterns of four tree species of different phenologies were studied along an elevational gradient, in which soil moisture availability increases with altitude. Main interest was the influence of variation in soil moisture, vapor pressure deficit, species (representing phenology), elevation, and tree diameter on water use. Special emphasis was put on the stem succulent, deciduous Ceiba trichistandra, as high water use rates and drought coping involving stem succulence was to be expected. Tree water use rates increased linearly with diameter across species at high soil water content. However, when soil moisture declined, sap flux densities of the species responded differently. The stem succulent, deciduous Ceiba and other deciduous tree species reduced sap flux sensitively, whereas sap flux densities of the evergreen (broad leaved) Capparis scabrida were increasing. This was also reflected in diurnal hysteresis loops of sap flux vs. vapor pressure deficit (VPD) of the air. Under dry soil conditions, Ceiba and other deciduous tree species had much smaller areas in the hysteresis loop, whereas the area of Capparis was largely enhanced compared to wet conditions. The evergreen Capparis potentially had access to deeper soil water resources as water use patterns suggest that top soil drought was tolerated. The deciduous species followed a drought avoidance strategy by being leafless in the dry season. The stem succulent deciduous Ceiba flushed leaves at the end of the dry season before the rainy season began and also re-flushed early in the dry season after a rain event; however, water use rates at this occasion remained low. Ceiba was also ready for fast and strong response in water use when conditions were most favorable during the wet season. The study thus indicates a strong influence of species' drought coping strategy on water use patterns in tropical dry forests.
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    Complete mitochondrial genome of a woolly mammoth (Mammuthus primigenius) from Maly Lyakhovsky Island (New Siberian Islands, Russia) and its phylogenetic assessment 

    Kornienko, Igor V.; Faleeva, Tatiana G.; Oreshkova, Natalia V.; Grigoriev, Semyon E.; Grigoreva, Lena V.; Simonov, Evgeniy P.; Kolesnikova, Anna I.; Putintseva, Yuliya A.; Krutovsky, Konstantin V.
    Mitochondrial DNA Part B 2018; 3(2) p.596-598
    We present a complete sequence and an annotation of the mitochondrial genome of the woolly mammoth (Mammuthus primigenius) found in 2012 on Maly Lyakhovsky Island (North-Eastern Siberia, Russia). The genome was 16,851 bp long and contained 13 protein-coding, 22 tRNA, and 2 rRNA genes. It was AT reach (61.3%) with A¼32.9%, T¼28.4%, C¼25.3%, and G¼13.4%.
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    Adapting Chinese Forest Operations to Socio-Economic Developments: What is the Potential of Plantations for Strengthening Domestic Wood Supply? 

    Hoffmann, Stephan; Jaeger, Dirk; Shuirong, Wu
    Sustainability 2018; 10(4) p.1-19: Art. 1042
    Over recent decades, China’s forestry sector went through a transition phase characterized by a management and institutional reform process, with a constant rethinking of the ecological and societal role of forests within a unique political system. Nevertheless, despite impressive achievements in forest restoration and conservation efforts, the enhancement of ecosystem services and forest area expansion through plantation development, China was not able to improve its domestic timber supply capacities according to its demands. Consequently, the continually growing wood processing industry is facing a severe demand-and-supply gap, causing high dependencies on timber imports. Outdated forest operations practices, dominated by manual labour, are not able to meet supply demands or to implement new silvicultural strategies for enhancing forest quality and productivity and are a widely unnoted disruption of a sustainable development. Therefore, this review presents the status quo of China’s forest operations sector, how it is shaped by forest policy reforms and recent socio-economic developments. In addition, suggestions are developed how the sector can progress through policy adaptations in order to develop sustainable timber supply capacities based on a domestic plantation sector.
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    Wildlife Warning Reflectors' Potential to Mitigate Wildlife-Vehicle Collisions - A Review on the Evaluation Methods 

    Benten, Anke; Annighöfer, Peter; Vor, Torsten
    Frontiers in Ecology and Evolution 2018; 6 p.1-12: Art. 37
    Wildlife-vehicle collisions (WVC) produce considerable costs in road traffic due to human fatalities as well as ecological and economic losses. Multiple mitigation measures have been developed over the past decades to separate traffic and wildlife, to warn humans, or to prevent wildlife from entering roads. Among these, wildlife warning reflectors (WWR) have been frequently implemented, although their effectiveness remains a subject of discussion due to conflicting study results. Here we present a literature review on the effectiveness of WWR for N = 76 studies, including their methodological differences, such as the type of WWR (model and color), study conditions, and study designs. We used boosted regression trees to analyse WVC-data addressed in the literature to compare WWR effectiveness depending on the study design, study conditions, effective study duration, length of the tested sections, time period of the study, data source, reflector type, and animal species. Our analyses revealed no clear evidence for the effectiveness of WWR in preventing WVC. Instead, our meta-analysis showed that most studies indicating significant effects of WWR on the occurrence of WVC may be biased due to insufficiencies in study design and/or the approach of WVC data acquisition. Our computation of log response ratios (LRRWVC) showed that only studies applying a before-after (BA) design concluded that WWR were effective. Moreover, BRT modeling revealed that only studies of <12 months effective study duration and <5 km test site length indicated that WWR might lower WVC. Based on the vulnerability to confounding factors of WWR-study designs applied in the past, this review suggests the standardization of study conditions, including a before-after control-impact (BACI) or a cross-over study design with spatial and temporal control sections, a minimum test site length and a minimum study duration.
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    Forest Soil Phosphorus Resources and Fertilization Affect Ectomycorrhizal Community Composition, Beech P Uptake Efficiency, and Photosynthesis 

    Zavišić, Aljosa; Yang, Nan; Marhan, Sven; Kandeler, Ellen; Polle, Andrea
    Frontiers in Plant Science 2018; 9 p.1-13: Art. 463
    Phosphorus (P) is an important nutrient, whose plant-available form phosphate is often low in natural forest ecosystems. Mycorrhizal fungi mine the soil for P and supply their host with this resource. It is unknown how ectomycorrhizal communities respond to changes in P availability. Here, we used young beech (Fagus sylvatica L.) trees in natural forest soil from a P-rich and P-poor site to investigate the impact of P amendment on soil microbes, mycorrhizas, beech P nutrition, and photosynthesis. We hypothesized that addition of P to forest soil increased P availability, thereby, leading to enhanced microbial biomass and mycorrhizal diversity in P-poor but not in P-rich soil.We expected that P amendment resulted in increased plant P uptake and enhanced photosynthesis in both soil types. Young beech trees with intact soil cores from a P-rich and a P-poor forest were kept in a common garden experiment and supplied once in fall with triple superphosphate. In the following summer, labile P in the organic layer, but not in the mineral top soil, was significantly increased in response to fertilizer treatment. P-rich soil contained higher microbial biomass than P-poor soil. P treatment had no effect on microbial biomass but influenced the mycorrhizal communities in P-poor soil and shifted their composition toward higher similarities to those in P-rich soil. Plant uptake efficiency was negatively correlated with the diversity of mycorrhizal communities and highest for trees in P-poor soil and lowest for fertilized trees. In both soil types, radioactive P tracing (H3 33PO4) revealed preferential aboveground allocation of new P in fertilized trees, resulting in increased bound P in xylem tissue and enhanced soluble P in bark, indicating increased storage and transport. Fertilized beeches from P-poor soil showed a strong increase in leaf P concentrations from deficient to luxurious conditions along with increased photosynthesis. Based on the divergent behavior of beech in P-poor and P-rich forest soil, we conclude that acclimation of beech to low P stocks involves dedicated mycorrhizal community structures, low P reserves in storage tissues and photosynthetic inhibition, while storage and aboveground allocation of additional P occurs regardless of the P nutritional status.
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    Land-use change in oil palm dominated tropical landscapes-An agent-based model to explore ecological and socio-economic trade-offs. 

    Dislich, Claudia; Hettig, Elisabeth; Salecker, Jan; Heinonen, Johannes; Lay, Jann; Meyer, Katrin M.; Wiegand, Kerstin; Tarigan, Suria
    PLOS ONE 2018; 13(1): Art. e0190506
    Land-use changes have dramatically transformed tropical landscapes. We describe an ecological-economic land-use change model as an integrated, exploratory tool used to analyze how tropical land-use change affects ecological and socio-economic functions. The model analysis seeks to determine what kind of landscape mosaic can improve the ensemble of ecosystem functioning, biodiversity, and economic benefit based on the synergies and trade-offs that we have to account for. More specifically, (1) how do specific ecosystem functions, such as carbon storage, and economic functions, such as household consumption, relate to each other? (2) How do external factors, such as the output prices of crops, affect these relationships? (3) How do these relationships change when production inefficiency differs between smallholder farmers and learning is incorporated? We initialize the ecological-economic model with artificially generated land-use maps parameterized to our study region. The economic sub-model simulates smallholder land-use management decisions based on a profit maximization assumption. Each household determines factor inputs for all household fields and decides on land-use change based on available wealth. The ecological sub-model includes a simple account of carbon sequestration in above-ground and below-ground vegetation. We demonstrate model capabilities with results on household consumption and carbon sequestration from different output price and farming efficiency scenarios. The overall results reveal complex interactions between the economic and ecological spheres. For instance, model scenarios with heterogeneous crop-specific household productivity reveal a comparatively high inertia of land-use change. Our model analysis even shows such an increased temporal stability in landscape composition and carbon stocks of the agricultural area under dynamic price trends. These findings underline the utility of ecological-economic models, such as ours, to act as exploratory tools which can advance our understanding of the mechanisms underlying the trade-offs and synergies of ecological and economic functions in tropical landscapes.
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    Morphologic and Chemical Properties of PMMA/ATH Layers with Enhanced Abrasion Resistance Realised by Cold Plasma Spraying at Atmospheric Pressure 

    Wallenhorst, L.; Rerich, R.; Vovk, M.; Dahle, S.; Militz, H.; Ohms, G.; Viöl, W.
    Advances in Condensed Matter Physics 2018; 2018 p.1-11
    This study investigated themorphologic and chemical properties of coatings based on PMMA/ATH powder and deposited by cold plasma spraying on wood and glass. Since the deposition of pure PMMA/ATH powder with air as process gas yielded coatings with insufficient abrasion resistance, two modifications of the basic process were investigated. Previous studies showed that replacing air as process gas with forming gas did not enhance the abrasion resistance, but the addition of a phenol-formaldehyde resin (PF) succeeded in stabilising the particle coatings. In thiswork, results frommorphologic and chemical analysis suggestedanencasement of the PMMA/ATH particles by plasma-modified PF and thus a fusion of individual particles, explaining the enhanced bonding. Moreover, adhesion tests confirmed an outstanding bonding between the coating and wood as well as glass, which is assumed to result from interactions between the PF’s hydroxyl groups and functional groups on the substrates’ surfaces. Studies on the wettability revealed a hydrophobic character of such coatings, therefore generally indicating a possible application, for example, to reduce water uptake by wooden materials.
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    Drought effects on the tissue- and cell-specific cytokinin activity in poplar. 

    Paul, Shanty; Wildhagen, Henning; Janz, Dennis; Polle, Andrea
    AoB PLANTS 2018; 10(1) p.1-18: Art. plx067
    Climate change with increasing periods of drought is expected to reduce the yield of biomass crops such as poplars. To combat yield loss, it is important to better understand the molecular mechanisms that control growth under drought. Here, the goal was to resolve the drought-induced changes of active cytokinins, a main growth hormone in plants, at the tissue level in different cell types and organs of poplars (Populus×canescens) in comparison with growth, biomass, leaf shedding, photosynthesis and water potential. Since cytokinin response is mediated by type-A response regulators,ARR5::GUSreporter lines were used to map cytokinin activity histochemically. The expression ofPtaRR3andPtaRR10was examined in different stem sections. Young leaves showed strong cytokinin activity in the veins and low staining under drought stress, accompanied by diminished leaf expansion. Leaf scars, at positions where drought-shedding occurred, showed strong reduction of cytokinin activity. The pith in the differentiation zone of stem showed high cytokinin activity with distinct, very active parenchymatic cells and enhanced activity close to primary xylem. This pattern was maintained under drought but the cytokinin activity was reduced. Mature phloem parenchymatic cells showed high cytokinin activity and mature wood showed no detectable cytokinin activity. Cytokinin activity in the cambium was apparent as a clear ring, which faded under drought. Xylem-localized cytokinin activities were also mirrored by the relative expression ofPtaRR3, whereasPtaRR10showed developmental but no drought-induced changes. Primary meristems exhibited high cytokinin activity regardless of drought stress, supporting a function of this phytohormone in meristem maintenance, whereas declining cytokinin activities in apical pith tissues and cambium of drought-stressed poplars linked cytokinin in these cell types with the control of primary and secondary growth processes. Changes in cytokinin activity further imply a role in drought avoidance mechanisms of poplars, especially in the reduction of leaf area.
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    Changes of Scots Pine Phyllosphere and Soil Fungal Communities during Outbreaks of Defoliating Insects 

    Beule, Lukas; Grüning, Maren; Karlovsky, Petr; l-M-Arnold, Anne
    Forests 2017; 8(12)
    Outbreaks of forest pests increase with climate change, and thereby may affect microbial communities and ecosystem functioning. We investigated the structure of phyllosphere and soil microbial communities during defoliation by the nun moth (Lymantria monacha L.) (80% defoliation) and the pine tree lappet (Dendrolimus pini L.) (50% defoliation) in Scots pine forests (Pinus sylvestris L.) in Germany. Ribosomal RNA genes of fungi and bacteria were amplified by polymerase chain reaction (PCR), separated by denaturing gradient gel electrophoresis (DGGE), and subsequently sequenced for taxonomic assignments. Defoliation by both pests changed the structure of the dominant fungal (but not bacterial) taxa of the phyllosphere and the soil. The highly abundant ectomycorrhizal fungal taxon (Russula sp.) in soils declined, which may be attributed to insufficient carbohydrate supply by the host trees and increased root mortality. In contrast, potentially pathogenic fungal taxa in the phyllosphere increased during pest outbreaks. Our results suggest that defoliation of pines by insect pest, change the structure of fungal communities, and thereby indirectly may be contributing to aggravation of tree health.
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    Exploring Niches for Short-Season Grain Legumes in Semi-Arid Eastern Kenya - Coping with the Impacts of Climate Variability. 

    Sennhenn, Anne; Njarui, Donald M. G.; Maass, Brigitte L.; Whitbread, Anthony M.
    Frontiers in plant science 2017; 8: Art. 699
    Climate variability is the major risk to agricultural production in semi-arid agroecosystems and the key challenge to sustain farm livelihoods for the 500 million people who inhabit these areas worldwide. Short-season grain legumes have great potential to address this challenge and help to design more resilient and productive farming systems. However, grain legumes display a great diversity and differ widely in growth, development, and resource use efficiency. Three contrasting short season grain legumes common bean (Phaseolus vulgaris L.), cowpea (Vigna unguiculata (L.) Walp.] and lablab [Lablab purpureus (L.) Sweet] were selected to assess their agricultural potential with respect to climate variability and change along the Machakos-Makueni transect in semi-arid Eastern Kenya. This was undertaken using measured data [a water response trial conducted during 2012/13 and 2013/14 in Machakos, Kenya] and simulated data using the Agricultural Production System sIMulator (APSIM). The APSIM crop model was calibrated and validated to simulate growth and development of short-season grain legumes in semi-arid environments. Water use efficiency (WUE) was used as indicator to quantify the production potential. The major traits of adaptation include early flowering and pod and seed set before the onset of terminal drought. Early phenology together with adapted canopy architecture allowed more optimal water use and greater partitioning of dry matter into seed (higher harvest index). While common bean followed a comparatively conservative strategy of minimizing water loss through crop transpiration, the very short development time and compact growth habit limited grain yield to rarely exceed 1,000 kg ha-1. An advantage of this strategy was relatively stable yields independent of in-crop rainfall or season length across the Machakos-Makueni transect. The growth habit of cowpea in contrast minimized water loss through soil evaporation with rapid ground cover and dry matter production, reaching very high grain yields at high potential sites (3,000 kg ha-1) but being highly susceptible to in-season drought. Lablab seemed to be best adapted to dry environments. Its canopy architecture appeared to be best in compromising between the investment in biomass as a prerequisite to accumulate grain yield by minimizing water loss through soil evaporation and crop transpiration. This lead to grain yields of up to 2,000 kg ha-1 at high potential sites and >1,000 kg ha-1 at low potential sites. The variance of observed and simulated WUE was high and no clear dependency on total rainfall alone was observed for all three short-season grain legumes, highlighting that pattern of water use is also important in determining final WUEbiomass and WUEgrain. Mean WUEgrain was lowest for cowpea (1.5-3.5 kggrain ha-1 mm-1) and highest for lablab (5-7 kggrain ha-1 mm-1) reflecting the high susceptibility to drought of cowpea and the good adaptation to dry environments of lablab. Results highlight that, based on specific morphological, phonological, and physiological characteristics, the three short-season grain legumes follow different strategies to cope with climate variability. The climate-smart site-specific utilization of the three legumes offers promising options to design more resilient and productive farming systems in semi-arid Eastern Kenya.
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    Modeling Allometric Relationships in Leaves of Young Rapeseed (Brassica napus L.) Grown at Different Temperature Treatments. 

    Tian, Tian; Wu, Lingtong; Henke, Michael; Ali, Basharat; Zhou, Weijun; Buck-Sorlin, Gerhard
    Frontiers in plant science 2017; 8: Art. 313
    Functional-structural plant modeling (FSPM) is a fast and dynamic method to predict plant growth under varying environmental conditions. Temperature is a primary factor affecting the rate of plant development. In the present study, we used three different temperature treatments (10/14°C, 18/22°C, and 26/30°C) to test the effect of temperature on growth and development of rapeseed (Brassica napus L.) seedlings. Plants were sampled at regular intervals (every 3 days) to obtain growth data during the length of the experiment (1 month in total). Total leaf dry mass, leaf area, leaf mass per area (LMA), width-length ratio, and the ratio of petiole length to leaf blade length (PBR), were determined and statistically analyzed, and contributed to a morphometric database. LMA under high temperature was significantly smaller than LMA under medium and low temperature, while leaves at high temperature were significantly broader. An FSPM of rapeseed seedlings featuring a growth function used for leaf extension and biomass accumulation was implemented by combining measurement with literature data. The model delivered new insights into growth and development dynamics of winter oilseed rape seedlings. The present version of the model mainly focuses on the growth of plant leaves. However, future extensions of the model could be used in practice to better predict plant growth in spring and potential cold damage of the crop.
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    Comparative transcriptomic analysis reveals the roles of overlapping heat-/drought-responsive genes in poplars exposed to high temperature and drought. 

    Jia, Jingbo; Zhou, Jing; Shi, Wenguang; Cao, Xu; Luo, Jie; Polle, Andrea; Luo, Zhi-Bin
    Scientific reports 2017-02-24; 7: Art. 43215
    High temperature (HT) and drought are both critical factors that constrain tree growth and survival under global climate change, but it is surprising that the transcriptomic reprogramming and physiological relays involved in the response to HT and/or drought remain unknown in woody plants. Thus, Populus simonii saplings were exposed to either ambient temperature or HT combined with sufficient watering or drought. RNA-sequencing analysis showed that a large number of genes were differentially expressed in poplar roots and leaves in response to HT and/or desiccation, but only a small number of these genes were identified as overlapping heat-/drought-responsive genes that are mainly involved in RNA regulation, transport, hormone metabolism, and stress. Furthermore, the overlapping heat-/drought-responsive genes were co-expressed and formed hierarchical genetic regulatory networks under each condition compared. HT-/drought-induced transcriptomic reprogramming is linked to physiological relays in poplar roots and leaves. For instance, HT- and/or drought-induced abscisic acid accumulation and decreases in auxin and other phytohormones corresponded well with the differential expression of a few genes involved in hormone metabolism. These results suggest that overlapping heat-/drought-responsive genes will play key roles in the transcriptional and physiological reconfiguration of poplars to HT and/or drought under future climatic scenarios.
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    Realization and Extension of the Xfrog Approach for Plant Modelling in the Graph-Grammar Based Language XL 

    Henke, Michael; Kniemeyer, Ole; Kurth, Winfried
    Computing and Informatics 2017; 36(1) p.33-54
    Two well-known approaches for modelling virtual vegetation are grammar- based methods (L-systems) and the Xfrog method, which is based on graph transformations expanding \multiplier" nodes. We show that both approaches can be uni ed in the framework of \relational growth grammars", a variant of parallel graph grammars. We demonstrate this possibility and the synergistic bene ts of the combination of both methods at simple plant models which were processed using our open-source software GroIMP.
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    Atmosphereic Pressure Plasma Coating of Wood and MDF with Polyester Powder 

    Köhler, Robert; Sauerbier, Philipp; Militz, Holger; Viöl, Wolfgang
    Coatings 2017; 7(10)
    In this study, polyester powder based on iso- and teraphthalic acid was deposited with an atmospheric plasma jet. The powder was fed into the effluent plasma zone and deposited on European beech wood (Fagus sylvatica L.), Grand fir (Abies grandis Lindl.) and medium density fiberboard (MDF). The substrates were annealed subsequent to the coating process. To exclude decomposition of the polyester layers by the plasma treatment, the surface chemistry of the layers has been examined by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) and compared with the polyester powder reference. Furthermore, topographical investigations were carried out using laser scanning microscopy (LSM). Adhesive strength of the layers was evaluated by dolly test and gloss measurements with a goniophotometer. The deposited layers showed no chemical changes compared to the reference. The adhesive strength of the layer met practical requirements of >1 MPa. It was demonstrated that the deposition of a macroscopic layer is possible without a pretreatment or the usage of additives. Therefore this coating process by atmospheric pressure plasma for wood and wood based materials could represent an environmental-friendly alternative to conventional coating methods.
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    A holistic approach to determine tree structural complexity based on laser scanning data and fractal analysis 

    Seidel, Dominik
    Ecology and Evolution p.1-7
    The three-dimensional forest structure affects many ecosystem functions and services provided by forests. As forests are made of trees it seems reasonable to approach their structure by investigating individual tree structure. Based on three-dimensional point clouds from laser scanning, a newly developed holistic approach is presented that enables to calculate the box dimension as a measure of structural complexity of individual trees using fractal analysis. It was found that the box dimension of trees was significantly different among the tested species, among trees belonging to the same species but exposed to different growing conditions (at gap vs. forest interior) or to different kinds of competition (intraspecific vs. interspecific). Furthermore, it was shown that the box dimension is positively related to the trees’ growth rate. The box dimension was identified as an easy to calculate measure that integrates the effect of several external drivers of tree structure, such as competition strength and type, while simultaneously providing information on structure-related properties, like tree growth.
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    A new instrument for stable isotope measurements of C-13 and O-18 in CO2 - instrument performance and ecological application of the Delta Ray IRIS analyzer 

    Braden-Behrens, Jelka; Yan, Yuan; Knohl, Alexander
    Atmospheric Measurement Techniques 2017; 10(11) p.4537-4560
    We used the recently developed commercially available Delta Ray isotope ratio infrared spectrometer (IRIS) to continuously measure the CO2 concentration c and its isotopic composition δ13C and δ18O in a managed beech forest in central Germany. Our objectives are (a) to characterize the Delta Ray IRIS and evaluate its internal calibration procedure and (b) to quantify the seasonal variability of c, δ13C, δ18O and the isotopic composition of nighttime net ecosystem CO2 exchange (respiration) Reco13C and Reco18O derived from Keeling plot intercepts. The analyzer's minimal Allan deviation (as a measure of precision) was below 0.01 ppm for the CO2 concentration and below 0.03 ‰ for both δ values. The potential accuracy (defined as the 1σ deviation from the respective linear regression that was used for calibration) was approximately 0.45 ppm for c, 0.24 ‰ for 13C and 0.3 ‰ for 18O. For repeated measurements of a target gas in the field, the long-term standard deviation from the mean was 0.3 ppm for c and below 0.3 ‰ for both δ values. We used measurements of nine different inlet heights to evaluate the isotopic compositions of nighttime net ecosystem CO2 exchange Reco13C and Reco18O in a 3-month measurement campaign in a beech forest in autumn 2015. During this period, an early snow and frost event occurred, coinciding with a change in the observed characteristics of both Reco13C and Reco18O. Before the first snow, Reco13C correlated significantly (p  <  10−4) with time-lagged net radiation Rn, a driver of photosynthesis and photosynthetic discrimination against 13C. This correlation became insignificant (p  >  0.1) for the period after the first snow, indicating a decoupling of δ13C of respiration from recent assimilates. For 18O, we measured a decrease of 30 ‰ within 10 days in Reco18O after the snow event, potentially reflecting the influence of 18O depleted snow on soil moisture. This decrease was 10 times larger than the corresponding decrease in δ18O in ambient CO2 (below 3 ‰) and took 3 times longer to recover (3 weeks vs. 1 week). In summary, we conclude that (1) the new Delta Ray IRIS with its internal calibration procedure provides an opportunity to precisely and accurately measure c, δ13C and δ18O at field sites and (2) even short snow or frost events might have strong effects on the isotopic composition (in particular 18O) of CO2 exchange on an ecosystem scale.
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    Dragonflies and damselflies of the EFForTS study area in Jambi and Bogor (Indonesia) 

    Rembold, Katja; Schröter, Asmus
    Macroecology & Biogeography, Faculty of Forest Sciences and Forest Ecology of the University of Goettingen, 2017
    In context of the vegetation surveys carried out by EFForTS subproject B06, we photographed quite a lot of dragonflies and damselflies inside and near the core plots in Jambi Province (Fig. 1) and in Bogor. The core plots in Jambi cover four land‐use systems: lowland rainforest, jungle rubber agroforest, rubber plantations, and oil palm plantations. With this booklet, we would like to share those photographs and their identifications as they might be useful for others. The color guide is divided into Anisoptera (dragonflies) and Zygoptera (damselflies) and arranged alphabetically by families. The current version includes 54 species from 9 families. Please note that this guide is not based on a systematical study, but was put together just for fun.
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    Common wayside plants of Jambi Province (Sumatra, Indonesia) 

    Rembold, Katja; Tjitrosoedirdjo, Sri Sudarmiyati; Kreft, Holger
    Faculty of Forest Sciences and Forest Ecology of the University of Goettingen, 2017
    In context of the vegetation surveys carried out by EFForTS subproject B06, we documented common vascular plant species inside and near the core plots in Jambi Province (Fig. 1, for details see Rembold et al. 2017). The core plots cover four land‐use systems: lowland rainforest, jungle rubber agroforest, rubber plantations, and oil palm plantations. With this booklet, we would like to share photographs of selected common or conspicuous species and their identifications as they might be useful for others. The color guide is divided into pteridophytes (lycophytes and ferns) and angiosperms and arranged alphabetically by families. The current version includes 94 plant species from 44 families and provides information about which species are native or alien to Indonesia. For more plant pictures, see the EFForTS Sumatra plant database that is currently under development (http://134.76.19.22/sumatra/home). Please be aware that species and family names are subject to changes due to identification updates or changes in plant taxonomy.
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