Silvicultural practices for wild pear

The research objective is to construct a model for crown radius (CR) based on DBH and significant quantifiers for wild pear (Pyrus pyraster), using regression analyses, to develop guidelines for silvicultural practices for wild pear. To establish the model empirical data of a wild pear population in Western Germany was collected. Site measurements include prevailing vegetation, soil characteristics, location and neighbouring trees. Tree measurements include DBH, height, crown radius and quality characteristics: living branches, forking, bending and spiral grain. 52 trees have been measured of which 41 have been used for modelling purposes. Selection criteria for the model are residual plots and coefficient of determination (R²). In order to find a linear relationship, (semi-) logarithmic transformations of the dependent and independent variables have taken place. A backward variable elimination from a full model was used to find significant predictors. The logarithmic model is selected best as residual plots show a homoscedastic distribution and follow a normal distribution around the zero-line. The R² of 0.6101 gives an indication of a significant relationship. The final relation can be formulated as:CR=e^(0.61388∗ln(DBH)−0.75029), where CR in m and DBH in cm. No other independent variables than DBH have been significant. From the derived model, tree spacing and number of stems per ha can be calculated at any DBH. Based on collected data and the model silvicultural guidelines for a pure and two mixed wild pear stands including planting density and layout, pruning, thinning and regeneration cutting are established

Species co-occurrence and management intensity modulate habitat preferences of forest birds

Background Species co-occurrences can have profound effects on the habitat use of species, and therefore habitat structure alone cannot fully explain observed abundances. To account for this aspect of community organization, we developed multi-species abundance models, incorporating the local effect of co-occurring and potentially associated species, alongside with environmental predictors, linked mainly to forest management intensity. We coupled it with a landscape-scale analysis to further examine the role of management intensity in modifying the habitat preferences in connection with the landscape context. Using empirical data from the Black Forest in southern Germany, we focused on the forest bird assemblage and in particular on the cavity-nesting and canopy-foraging guilds. We included in the analysis species that co-occur and for which evidence suggests association is likely. Results Our findings show that the local effect of species associations can mitigate the effects of management intensity on forest birds. We also found that bird species express wider habitat preferences in forests under higher management intensity, depending on the landscape context. Conclusions We suspect that species associations may facilitate the utilization of a broader range of environmental conditions under intensive forest management, which benefits some species over others. Networks of associations may be a relevant factor in the effectiveness of conservation-oriented forest management

Woodpecker cavity establishment in managed forests: relative rather than absolute tree size matters

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Where are we now with European forest multi-taxon biodiversity and where can we head to?

The European biodiversity and forest strategies rely on forest sustainable management (SFM) to conserve forest biodiversity. However, current sustainability assessments hardly account for direct biodiversity indicators. We focused on forest multi-taxon biodiversity to: i) gather and map the existing information; ii) identify knowledge and research gaps; iii) discuss its research potential. We established a research network to fit data on species, standing trees, lying deadwood and sampling unit description from 34 local datasets across 3591 sampling units. A total of 8724 species were represented, with the share of common and rare species varying across taxonomic classes: some included many species with several rare ones (e.g., Insecta); others (e.g., Bryopsida) were represented by few common species. Tree-related structural attributes were sampled in a subset of sampling units (2889; 2356; 2309 and 1388 respectively for diameter, height, deadwood and microhabitats). Overall, multitaxon studies are biased towards mature forests and may underrepresent the species related to other developmental phases. European forest compositional categories were all represented, but beech forests were overrepresented as compared to thermophilous and boreal forests. Most sampling units (94%) were referred to a habitat type of conservation concern. Existing information may support European conservation and SFM strategies in: (i) methodological harmonization and coordinated monitoring; (ii) definition and testing of SFM indicators and thresholds; (iii) data-driven assessment of the effects of environmental and management drivers on multi-taxon forest biological and functional diversity, (iv) multi-scale forest monitoring integrating in-situ and remotely sensed information. Forest biodiversity Multi-taxon Sustainable management Biodiversity conservation Forest stand structurepublishedVersio

Genomic perspectives on the evolution of fungal entomopathogenicity in Beauveria bassiana

The ascomycete fungus Beauveria bassiana is a pathogen of hundreds of insect species and is commercially produced as an environmentally friendly mycoinsecticide. We sequenced the genome of B. bassiana and a phylogenomic analysis confirmed that ascomycete entomopathogenicity is polyphyletic, but also revealed convergent evolution to insect pathogenicity. We also found many species-specific virulence genes and gene family expansions and contractions that correlate with host ranges and pathogenic strategies. These include B. bassiana having many more bacterial-like toxins (suggesting an unsuspected potential for oral toxicity) and effector-type proteins. The genome also revealed that B. bassiana resembles the closely related Cordyceps militaris in being heterothallic, although its sexual stage is rarely observed. A high throughput RNA-seq transcriptomic analysis revealed that B. bassiana could sense and adapt to different environmental niches by activating well-defined gene sets. The information from this study will facilitate further development of B. bassiana as a cost-effective mycoinsecticide

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Analysis of frequency-smearing models simulating hearing loss

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (leaves 189-191).by Alan T. Asbeck.M.Eng

Tree microhabitat abundance and richness in Central European montane forests as indicators for future old growth elements

The continued provision of old-growth elements in forest landscapes has been identified as a critical factor for biodiversity conservation in Central Europe. A well-established method of estimating the potential of forests to maintain biodiversity is to quantify tree microhabitat structures. Our aim is to predict the microhabitat abundance and richness for collectives of potential habitat trees (15 largest trees per plot).  Microhabitats were inventoried on 2085 trees across 139 plots (each 1 ha) and assessed based on a detailed catalogue comprising 64 different microhabitat structures in montane forests of the Black Forest, southwest Germany. We tested the influence of forest management, forest cover in surrounding landscape, forest type, structural complexity (number of standing dead trees), altitude and average tree size on the abundance and richness of microhabitats on living trees. Generalized linear models (GLM) were used to identify the significant drivers of abundance and richness of microhabitats. The results indicate that the abundance of microhabitats of the respective 15 trees is greater on plots located in higher altitudes. Increasing average tree diameter leads to significantly higher abundances and richness of microhabitats. The collectives of inventoried trees located in monospecific coniferous forests have the highest abundance but those in mixed-coniferous-broadleaved forests have the greatest richness of tree microhabitats. Additionally we explored to which degree specific microhabitat types are influenced by the forest variables. The occurrences of 11 out of 64 specific microhabitat structures show a relation to forest management, forest type, altitude or average tree diameter. Specific microhabitats are increasing in mixed-coniferous-broadleaved and in relation to average tree size. The altitude influences especially abundances of epiphytes on potential habitat trees.This study demonstrates that based on the selected forest attributes the average abundance and richness of microhabitats can be reasonably well predicted and the occurrence of specific microhabitats can be identified.peerReviewe

The Use of Tree-Related Microhabitats as Forest Biodiversity Indicators and to Guide Integrated Forest Management

International audiencePurpose of the Review The concept of tree-related microhabitats (TreMs) is an approach to assess and manage multi-taxon species richness in forest ecosystems. Owing to their provision of special habitat features, TreMs are of special interest as a surrogate biodiversity indicator. In particular, in retention forestry, TreMs have gained attention over the past decade as a selection criterion for retained structural elements such as habitat trees. This review seeks to (a) address the suitability of TreMs as biodiversity indicator in the context of retention forestry, (b) summarize drivers of TreM occurrence and the status quo of the implementation of TreM-based retention concepts in forest management, and (c) discuss current and future challenges to the use of TreMs as biodiversity indicator. Recent Findings The TreM concept originated in Europe where it is now increasingly implemented. Most studies of the quantity, quality, and diversity of TreMs are focused on tree species from this region, although it is increasingly applied in other contexts. In addition to tree species, tree dimensions and live status have been identified as the main drivers of TreM occurrence. One major remaining research challenge is to verify relationships between the occurrence and abundance of forest-dwelling species from different taxonomic groups and TreMs to improve the evidence basis of this concept and thus increase its integration in forest conservation approaches. TreMs are not the "silver bullet" indicator to quantify biodiversity of forest dwelling species, but they provide an important tool for forest managers to guide the selection of habitat trees for the conservation of the associated biodiversity