526,943 research outputs found

    PYTHIA hadronization process tuning in the GENIE neutrino interaction generator

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    9 pages, 7 figures, proceedings of the CETUP*-Workshop on Neutrino Interactions, July 22-31, 2014 at Lead/Dead Wood, South Dakota, USA9 pages, 7 figures, proceedings of the CETUP*-Workshop on Neutrino Interactions, July 22-31, 2014 at Lead/Dead Wood, South Dakota, USAv1: 9 pages, 7 figures, proceedings of the CETUP*-Workshop on Neutrino Interactions, July 22-31, 2014 at Lead/Dead Wood, South Dakota, USA. v2: 15 pages, 8 figures, 1 table, will be published by Journal of Physics G: Nuclear and Particle Physics (IoP

    Dead wood profile of a semi-natural boreal forest - implications for sampling

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    Dead wood profile of a forest is a useful tool for describing forest characteristics and assessing forest disturbance history. Nevertheless, there are few studies on dead wood profiles, including both coarse and fine dead wood, and on the effect of sampling intensity on the dead wood estimates. In a semi-natural boreal forest, we measured every dead wood item over 2 cm in diameter from 80 study plots. From eight plots, we further recorded dead wood items below 2 cm in diameter. Based on these data we constructed the full dead wood profile, i.e. the overall number of dead wood items and their distribution among different tree species, volumes of different size and decay stage categories. We discovered that while the number of small dead wood items was immense, their number dropped drastically from the diameter below 1 cm to diameters 2-3 cm. Different tree species had notably different abundance-diameter distribution patterns: spruce dead wood comprised most strikingly the smallest diameter fractions, whereas aspen dead wood comprised a larger share of large-diameter items. Most of the dead wood volume constituted of large pieces (>10 cm in diameter), and 62% of volume was birch. The variation in the dead wood estimates was small for the numerically dominant tree species and smallest diameter categories, but high for the sub-dominant tree species and larger size categories. In conclusion, the more the focus is on rare tree species and large dead wood items, the more comprehensive should the sampling be.Peer reviewe

    Standing dead trees contribute significantly to carbon budgets in Australian savannas

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    Previous estimates of greenhouse gas emissions from Australian savanna fires have incorporated on-ground dead wood but ignored standing dead trees. However, research from eucalypt woodlands in southern Queensland has shown that the two pools of dead wood burn at similar rates. New field data from semiarid savannas across northern Australia confirmed that standing dead trees comprise about four times the mass of on-ground dead wood. Further, the proportion of total woody biomass comprising dead wood increases with decreasing fire frequency and a decreasing proportion of late dry season (August to December) fires. This gives scope for increasing the carbon stock in the dead wood pool with a reduced fire frequency. Following a previously published approach to quantify total dead wood loads in savannas, new and previously collected data on tree stand structures were used across the whole savanna zone to quantify dead wood loads in equilibrium with historic fire regimes. New parameters are presented for calculating dead wood dynamics including dead trees in Australia's savannas. © 2020 IAWF

    Count on dead wood

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    Dead wood is acknowledged world-wide for its interconnection to biodiversity and sustainable forest management. In Sweden, today’s retention forestry requires measures to protect and create dead wood, which raise the need of inventory methods for estimating dead wood quantity and quality. There are however few evidence-based dead wood conservation value assessment methods, why this study aims at investigating the cost-efficiency and performance of two unconventional conservation assessment methods. The study was conducted in spruce dominated stands in Gävleborg county, which either had been clear-cut or set aside as retention. The Relascope method used a relascope to conduct dead wood measurements. The Triangle-transect method measured dead wood along three transects, established to form a triangle shape. A total inventory on sample plot level, the Sample plot method, was used for evaluation. Both methods were good proxies for dead wood volume on a plot level, though their performance for estimating volume and dead wood diversity varied dependent on forest types on stand level. Both methods were significantly faster than the Sample plot method. The results show a potential cost reduction in forest management, though further studies are needed to improve quantitative and qualitative measures of both methods before applying them in active forest management

    Saproxylic species are linked to the amount and isolation of dead wood across spatial scales in a beech forest

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    ContextDead wood is a key habitat for saproxylicspecies, which are often used as indicators of habitatquality in forests. Understanding how the amount andspatial distribution of dead wood in the landscapeaffects saproxylic communities is therefore importantfor maintaining high forest biodiversity.ObjectivesWe investigated effects of the amountand isolation of dead wood on the alpha and betadiversity of four saproxylic species groups, with afocus on how the spatial scale influences results.MethodsWe inventoried saproxylic beetles, wood-inhabiting fungi, and epixylic bryophytes and lichenson 62 plots in the Sihlwald forest reserve in Switzer-land. We used GLMs to relate plot-level speciesrichness to dead wood amount and isolation on spatialscales of 20–200 m radius. Further, we used GDMs todetermine how dead wood amount and isolationaffected beta diversity.ResultsA larger amount of dead wood increasedbeetle richness on all spatial scales, while isolation hadno effect. For fungi, bryophytes and lichens this wasonly true on small spatial scales. On larger scales ofour study, dead wood amount had no effect, whilegreater isolation decreased species richness. Further,we found no strong consistent patterns explaining betadiversity

    Detecting and characterizing downed dead wood using terrestrial laser scanning

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    Dead wood is a key forest structural component for maintaining biodiversity and storing carbon. Despite its important role in a forest ecosystem, quantifying dead wood alongside standing trees has often neglected when investigating the feasibility of terrestrial laser scanning (TLS) in forest inventories. The objective of this study was therefore to develop an automatic method for detecting and characterizing downed dead wood with a diameter exceeding 5 cm using multi-scan TLS data. The developed four-stage algorithm included (1) RANSAC-cylinder filtering, (2) point cloud rasterization, (3) raster image segmentation, and (4) dead wood trunk positioning. For each detected trunk, geometry-related quality attributes such as dimensions and volume were automatically determined from the point cloud. For method development and validation, reference data were collected from 20 sample plots representing diverse southern boreal forest conditions. Using the developed method, the downed dead wood trunks were detected with an overall completeness of 33% and correctness of 76%. Up to 92% of the downed dead wood volume were detected at plot level with mean value of 68%. We were able to improve the detection accuracy of individual trunks with visual interpretation of the point cloud, in which case the overall completeness was increased to 72% with mean proportion of detected dead wood volume of 83%. Downed dead wood volume was automatically estimated with an RMSE of 15.0 m(3)/ha (59.3%), which was reduced to 6.4 m(3)/ha (25.3%) as visual interpretation was utilized to aid the trunk detection. The reliability of TLS-based dead wood mapping was found to increase as the dimensions of dead wood trunks increased. Dense vegetation caused occlusion and reduced the trunk detection accuracy. Therefore, when collecting the data, attention must be paid to the point cloud quality. Nevertheless, the results of this study strengthen the feasibility of TLS-based approaches in mapping biodiversity indicators by demonstrating an improved performance in quantifying ecologically most valuable downed dead wood in diverse forest conditions.Peer reviewe

    Relative importance of habitat characteristics at multiple spatial scales for wood-dependent beetles in boreal forest

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    Species distributions are influenced by habitat conditions and ecological processes at multiple spatial scales. An understanding of the importance of habitat characteristics at different spatial scales is important when developing biodiversity conservation measures.We investigated the effect of habitat characteristics or amount at three spatial scales on the occurrence of saproxylic (=dead wood-dependent) beetles.Saproxylic beetles were sampled under the bark of dead wood in a managed forest landscape in central Sweden. We modelled the occurrence probability in dead wood items of 44 species (all species occurring in > 2 % of the items), based on dead wood item characteristics, forest stand characteristics, and habitat connectivity (i.e. area of potentially suitable forest stands in the surrounding of each stand), using hierarchical Bayesian regression.For the majority of species, dead wood item characteristics (especially tree species and whether standing or downed) were more important than measured stand characteristics and habitat connectivity. Whether the stands were clear-cuts, mature forests, or reserves affected some species, whereas the stand-level amount of dead wood per hectare was not important for any species. Habitat connectivity improved the occurrence models for about a half of the species, but there were both positive and negative relationships, and they were generally weak.Forest management should include creation and retention of a high diversity of dead wood to sustain habitat for all species. In a forest-dominated landscape, the spatial distribution of dead wood is of little importance for common saproxylic beetle species

    Resources of dead wood in the municipal forests in Warsaw

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    Dead wood plays an important role for the biodiversity of forest ecosystems and influences their proper development. This study assessed the amount of coarse woody debris in municipal forests in Warsaw (central Poland). Based on the forest site type, dominant tree species and age class, we stratified all complexes of the Warsaw urban forests in order to allocate 55 sample plots. For these plots, we determined the volume of dead wood including standing dead trees, coarse woody debris and broken branches as well as uprooted trees. We calculated the amount of dead wood in the distinguished site-species-age layers and for individual complexes. The volume of dead matter in municipal forests in Warsaw amounted to 38,761 m3, i.e. 13.7 m3/ha. The obtained results correspond to the current regulations concerning the amount of dead organic matter to be left in forests. Only in the Las Bielański complex (northern Warsaw) volume of dead wood is comparable to the level observed in Polish national parks or nature reserves, which is still far lower than the values found for natural forests. In general, municipal forests in Warsaw stand out positively in terms of dead wood quantity and a high degree of variation in the forms and dimensions of dead wood.Przemysław Szmi

    Effects of retained dead wood on predation pressure on herbivores in young pine forests

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    Retention of logging residue as dead wood could be a method to simultaneously increase biodiversity and predation rates of pest insects, in managed forests. Managed forests are generally low in diversity, and dead wood has been demonstrated to increase species diversity. Moreover, managed forests are predicted to suffer from higher frequency of insect outbreaks in the future, particularly in the northern hemisphere. In this study, we explore the effect of dead wood removal and addition in managed pine forest stands in Sweden on arthropod diversity and abundance and predation rates. We performed a controlled field experiment, focusing on logging residue type of dead wood. We used pitfall traps and sticky traps to measure arthropod diversity and abundance and plasticine larvae to assess predation rates. We specifically targeted generalist arthropods (i.e. non-wood living species), and predation rate on tree-dwelling larvae (corresponding to defoliating outbreak pests). We found no effect of dead wood addition on arthropod abundance or diversity, neither did we find an effect on predation rate. Despite the lack of effects in our study, we argue that dead wood can be an important component for both biodiversity of generalist arthropod and for pest control, but the effect may depend on both the specific arthropod group targeted and the specific life stage of the pest insect as well as on inherent components of the dead wood, such as age
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