1,721,068 research outputs found
From single trees to country-wide maps: Modeling mortality rates in Germany based on the Crown Condition Survey
Full text linkMost years in the period from 2018 to 2022 have been exceptionally dry in Central Europe. In Germany’s forests, this long-lasting drought has caused unprecedented tree mortality. Systematic ground-based surveys, such as the annual Crown Condition Survey, provide information on the vitality status of the different tree species and their mortality rates. However, models are needed to be able to map the spatial patterns of mortality for each tree species based on cause-effect relationships derived from field observations. In this study, logistic regression models were used to identify the most important drivers of mortality for the most important tree species in Germany. For this purpose, the dead and surviving trees from the Crown Condition Survey were combined with a large set of potential predictor variables from the domains of climate, topography, soil, land cover and deposition. After feature selection, the models were evaluated using the area under the curve (AUC) statistic. Norway spruce (Picea abies; AUC = 0.9) showed by far the greatest increase in mortality, with the country-wide average observed and predicted rates approaching almost 10% per year from 2020 to 2022, and much higher predicted rates at the regional level. Much of the spruce mortality was explained by the climatic water balance of the driest summer in previous years. The other main tree species also showed clear mortality responses to the drought conditions. However, in the case of European beech (Fagus sylvatica; AUC = 0.94) and Pedunculate and Sessile oak (Quercus robur and petraea; AUC = 0.88), the peaks in the time series of the country-wide mortality rates stayed below 1%. For these broadleaved species, mortality was more dependent on a range of site conditions, i.e., soil and topography. For Scots pine (Pinus sylvestris; AUC = 0.76), for which the observed mortality rate peaked at 1.2% in 2020, the given drivers could explain mortality only to a lesser degree than for the other species. The regression models were used for spatial prediction to produce country-wide maps of species-specific mortality rates at annual temporal and 100-m spatial resolution, covering all years from 1998 to 2022. The maps visualize the spatial patterns of mortality over time. The regions in western and central Germany, which were most seriously affected by spruce dieback can clearly be identified. The models and maps presented can be used for risk assessment, forest planning, and tree species selection, providing decision support for forest practitioners
Matching of forest restoration strategy to environmental conditions matters: evidence from south‐central Ethiopia
No full textAbstract Introduction Matching restoration strategies to environmental conditions is essential for successful forest landscape restoration in Ethiopia, but remains challenging due to limited guidance. Objectives We evaluated the performance of restoration strategies based on forest stand structure and biomass across varying soil, elevation, and climate conditions. We hypothesized that (1) fertile sites with favorable climates enhance restoration success, and (2) tending operations improve performance in fertile areas. Methods Using soil samples (0–10 cm) from 279 points in southern and central Ethiopia, and WorldClim climate data, we derived four environmental clusters through cluster analysis. We assessed forest structure attributes in plantations, woodlots (WL), boundary plantings (BP), and exclosures (EX) within these clusters. Results Active restoration strategies achieved top heights comparable to natural forests, which had the highest aboveground biomass (AGB). BP (57.75 m 2 /ha) and WL (25.55 m 2 /ha) had higher basal areas than EX with the lowest top height (approximately 6 m) and biomass. Actively restored sites had better soil conditions than the passive. Clusters differed by elevation, soil fertility (fert‐mid‐high; orga‐fert), and texture (clay‐precip; sandy‐low). Forest structure attributes were consistently higher in active than passive restoration strategies across clusters. Fertility‐linked clusters had higher structural attributes across restoration strategies. Plantations in clayey, high‐precipitation areas had the highest top height, AGB, and carbon storage. Clusters showed moderate correlation with mapped soil groups. Conclusions Results show that soil fertility and precipitation strongly influence restoration success. Additionally, soil groups offer limited guidance for site suitability. Finally, BP offer an opportunity to meet household wood needs.Implications for Practice Restoration site‐matching should consider climate, elevation, and soil conditions as opposed to soil group classification. Improving soil fertility and moisture can enhance restoration outcomes. Forest structural attribute differences among clusters suggest that certain landscapes may require the deployment of both sharing and sparing restoration strategy choice mechanisms. Boundary plantings offer a new opportunity to meet immediate community wood needs and mitigate climate change in the long term due to limited land demand. Exclosures are best suited for biodiversity over carbon storage even under poor conditions. Continuous monitoring helps to evaluate restoration benefits for livelihoods, climate, soil, and biodiversity.Abstract Introduction Matching restoration strategies to environmental conditions is essential for successful forest landscape restoration in Ethiopia, but remains challenging due to limited guidance. Objectives We evaluated the performance of restoration strategies based on forest stand structure and biomass across varying soil, elevation, and climate conditions. We hypothesized that (1) fertile sites with favorable climates enhance restoration success, and (2) tending operations improve performance in fertile areas. Methods Using soil samples (0–10 cm) from 279 points in southern and central Ethiopia, and WorldClim climate data, we derived four environmental clusters through cluster analysis. We assessed forest structure attributes in plantations, woodlots (WL), boundary plantings (BP), and exclosures (EX) within these clusters. Results Active restoration strategies achieved top heights comparable to natural forests, which had the highest aboveground biomass (AGB). BP (57.75 m 2 /ha) and WL (25.55 m 2 /ha) had higher basal areas than EX with the lowest top height (approximately 6 m) and biomass. Actively restored sites had better soil conditions than the passive. Clusters differed by elevation, soil fertility (fert‐mid‐high; orga‐fert), and texture (clay‐precip; sandy‐low). Forest structure attributes were consistently higher in active than passive restoration strategies across clusters. Fertility‐linked clusters had higher structural attributes across restoration strategies. Plantations in clayey, high‐precipitation areas had the highest top height, AGB, and carbon storage. Clusters showed moderate correlation with mapped soil groups. Conclusions Results show that soil fertility and precipitation strongly influence restoration success. Additionally, soil groups offer limited guidance for site suitability. Finally, BP offer an opportunity to meet household wood needs.Implications for Practice Restoration site‐matching should consider climate, elevation, and soil conditions as opposed to soil group classification. Improving soil fertility and moisture can enhance restoration outcomes. Forest structural attribute differences among clusters suggest that certain landscapes may require the deployment of both sharing and sparing restoration strategy choice mechanisms. Boundary plantings offer a new opportunity to meet immediate community wood needs and mitigate climate change in the long term due to limited land demand. Exclosures are best suited for biodiversity over carbon storage even under poor conditions. Continuous monitoring helps to evaluate restoration benefits for livelihoods, climate, soil, and biodiversity.Thünen-Institut https://doi.org/10.13039/50110002257
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Status and Dynamics of Forests in Germany
Full text linkLife sciences; Ecology ; Forestry; Soil science; Soil conservation; Sustainable development; Geobiolog
Status and Dynamics of Forests in Germany
Full text linkLife sciences; Ecology ; Forestry; Soil science; Soil conservation; Sustainable development; Geobiolog
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
