1,374 research outputs found
Video Project On Topics of NCAA Compliance
The NCAA Division I Manual is a very black-and-white ruling system that can easily be misunderstood or misinterpreted. To help increase understanding and illustrate some of the rules, this video project was created to cover four of the topics within the manual. The goal of the project was to present to administrators, coaches, and student-athletes at Division I institutions, some of the NCAA rules in a new, creative manner that helps understanding and retention of some of the current NCAA policies. The videos cover four topics: the safety exception, prospect visits, sports wagering, and social media. Each video covers some of the biggest points under each topic and illustrates those main points with examples to go along with the hostâs description of the bylaw being discussed. The goal of this project is to start a discussion that could lead to creating more videos in the same style
Paradigm Changes in Tropical Forestry and Steps towards a Green Economy: Elements of a Framework for Rural Development in Sudan
Rural regions are affected worldwide by outmigration, climate change and
volatile markets, resulting in their increasing marginalization. In Sudan wars and tribal
conflicts are additional threats. To counterbalance this, innovative strategies are required
on policy as well as on local producer level. To understand current trends of rural
development, a hermeneutic research approach is applied. This leads to the formulation
of the six paradigmatic development stages (1) pre-colonial, (2) colonial, (3)
independence and capital formation, (4) internationalization, (5) polarization and (6)
globalization. Paradigms are rooted in theories, have impact on policies, are determined
by a specific group of scholars and influence practice. In a first step, shifts between
paradigms and its consequences for rural development and forest management are
outlined and interpreted. In a further step current challenges of rural development are
investigated with regard to their roots in previous paradigms. Taken into account are
knowledge systems; colonial and postcolonial influences, which still determine current
land use; consequences of the modernization era, in which large agro-industries were
build up and experiences with the polarization stage, which led to the partial involvement
of the civil society and rural communities in decision making. The current globalization
paradigm is critically reviewed. Global governance instruments like conventions as well
as environmental service models are mostly based on market mechanisms and hardly
reach rural areas and local producers. It is proposed to follow different and alternative
development paths, giving more decision power to regional institutions, improving the
situation of small farms and building up social capital and small enterprises on a local
level. It is assumed that many experiences from previous development stages have hardly
been taken into account and need to be synthesized in development strategies. Concepts
of a âgreen economyâ are seen as a versatile fundament to discuss future strategies of
rural development in Sudan
Evidence of variant intra- and interspecific scaling of tree crown structure and relevance for allometric theory
General scaling rules or constants for metabolic and structural plant allometry as assumed by the theory of Euclidian geometric scaling (2/3-scaling) or metabolic scaling (3/4-scaling) may meet humanâs innate propensity for simplicity and generality of pattern and processes in nature. However, numerous empirical works show that variability of crown structure rather than constancy is essential for a treeâs success in coping with crowding. In order to link theory and empiricism, we analyzed the intra- and inter-specific scaling of crown structure for 52 tree species. The basis is data from 84 long-term plots of temperate monospecific forests under survey since 1870 and a set of 126 yield tables of angiosperm and gymnosperm forest tree species across the world. The study draws attention to (1) the intra-specific variation and correlation of the three scaling relationships: tree height versus trunk diameter, crown cross-sectional area versus trunk diameter, and tree volume versus trunk diameter, and their dependence on competition, (2) the inter-specific variation and correlation of the same scaling exponents (\documentclass[12pt]{minimal}
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\begin{document} {{\upalpha}}_{v,d} \end{document}) across 52 tree species, and (3) the relevance of the revealed variable scaling of crown structure for leaf organs and metabolic scaling. Our results arrive at suggesting a more extended metabolic theory of ecology which includes variability and covariation between allometric relationships as prerequisite for the individual plantâs competitiveness
Comparison of forest attributes derived from two terrestrial lidar systems.
Abstract
Terrestrial lidar (TLS) is an emerging technology for deriving forest attributes, including conventional inventory and canopy characterizations. However, little is known about the influence of scanner specifications on derived forest parameters. We compared two TLS systems at two sites in British Columbia. Common scanning benchmarks and identical algorithms were used to obtain estimates of tree diameter, position, and canopy characteristics. Visualization of range images and point clouds showed clear differences, even though both scanners were relatively high-resolution instruments. These translated into quantifiable differences in impulse penetration, characterization of stems and crowns far from the scan location, and gap fraction. Differences between scanners in estimates of effective plant area index were greater than differences between sites. Both scanners provided a detailed digital model of forest structure, and gross structural characterizations (including crown dimensions and position) were relatively robust; but comparison of canopy density metrics may require consideration of scanner attributes
Analysing forest development under changing environmental conditions â novel information for the forest management by combining models demonstrated for the forest enterprise Zittau
Waldwachstumsmodelle sind ein ideales Werkzeug, um Auswirkungen veränderter Umweltbedingungen auf das Wachstum der Bäume aufzuzeigen. Ziel des Teilprojektes âWaldwachstumsreaktionen und Systemprozesseâ im Rahmen von ENFORCHANGE war, durch die Kombination von Wachstumsmodellen mit unterschiedlichen methodischen Ansätzen regionale Auswirkungen standĂśrtlicher und klimatischer Veränderungen auf die Waldentwicklung zu analysieren und somit bessere Grundlagen fĂźr eine angepasste Forstbetriebsplanung zu schaffen. Anhand des physiologischen Wachstumsmodells BALANCE wurde der Einfluss der prognostizierten Klimaänderungen auf das Wachstum der Bäume abgeschätzt. Die fĂźr verschiedene Baumarten und regionaltypische Bestände gewonnenen Reaktionsmuster konnten anschlieĂend in das managementorientierte Wachstumsmodell SILVA Ăźbertragen werden. Die Entwicklung repräsentativer Waldbestände wurde in SILVA fĂźr einen Zeitraum von 30 Jahren simuliert, wobei verschiedene Nutzungsszenarien untersucht wurden, um Handlungsspielräume und mĂśgliche strategische Planungen fĂźr Forstbetriebe aufzuzeigen. Die gewonnenen Erkenntnisse fĂźr die praktische Betriebsplanung wurden am Beispiel des kommunalen Forstbetriebes Zittau dargestellt. Es wird deutlich, wie die Forstplanung von derartigen Szenarioanalysen profitieren kann. Die Simulationsrechnungen unter Annahme geänderter Klimaverhältnisse zeigen, dass die Bestände unter diesen Bedingungen ein verringertes ReaktionsvermĂśgen auf waldbauliche MaĂnahmen aufweisen, was insbesondere bei den Zuwächsen bemerkbar ist. Dabei haben Laubholzbestände, die bereits jetzt auf 27% der Betriebsfläche stocken, vermutlich eine Pufferwirkung und mildern die Auswirkungen der Klimaänderungen auf die Produktivität des Gesamtbetriebes ab.Forest growth models are versatile instruments for analysing the influence of environmental changes on plant growth. The aim of this study was to analyse possible adaptation strategies by model simulations combining different growth models. By using the process oriented growth model BALANCE we estimated the influence of climate change on tree growth. The reaction patterns of different and region specific forest stands were then implemented as algorithms in the management-oriented growth model SILVA. The growth of forest stands was simulated with SILVA over 30 years focussing on management options to test different adaption strategies. This approach of combining models with different paradigms is demonstrated for the forest enterprise Zittau. The results of the simulations for the Zittau enterprise convey how forest planning can profit by long term information from scenario analysis. Climate change simulations show that forest stands can loose capacity â e.g. increase capacity â to react on management measures. That means a loss of regulation alternatives for forest planning under the used climate change scenario. A hardwood percentage of 27% in the Zittau forest, on the other hand, possibly has a certain buffer function and moderates the climate change effects on production
Impact of Climate Trends and Drought Events on the Growth of Oaks (Quercus robur L. and Quercus petraea (Matt.) Liebl.) within and beyond Their Natural Range
Due to predicted climate change, it is important to know to what extent trees and forests
will be impacted by chronic and episodic drought stress. As oaks play an important role in European
forestry, this study focuses on the growth response of sessile oak (Quercus petraea (Matt.) Liebl.) and
pedunculate oak (Quercus robur (L.)) under contrasting climatic conditions. Analyses cover both site
conditions of their natural occurrence (Southern Germany and Northeast Italy) and site conditions
beyond their natural range (South Africa). The sites beyond their natural range represent possible
future climate conditions. Tree-ring series from three different sites were compared and analysed
using dendrochronological methods. The long-term growth development of oak trees appears to be
similar across the sites, yet the growth level over time is higher in the drier and warmer climate than
in the temperate zone. When compared with previous growth periods, growth models reveal that oak
trees grew more than expected during the last decades. A recent setback in growth can be observed,
although growth is still higher than the model predicts. By focusing on the short-term reactions of the
trees, distinct drought events and periods were discovered. In each climatic region, similar growth
reactions developed after drought periods. A decline in growth rate occurred in the second or third
year after the drought event. Oaks in South Africa are currently exposed to a warmer climate with
more frequent drought events. This climatic condition is a future prediction also for Europe. In view
of this climate change, we discuss the consequences of the long- and short- term growth behaviour of
oaks grown in the climate of South Africa for a tree species selection that naturally occurs in Europe
Tree species richness enhances stand productivity while stand structure can have opposite effects, based on forest inventory data from Germany and the United States of America
Background: In recent studies, mixed forests were found to be more productive than monocultures with everything else remaining the same.
Methods: To find out if this productivity is caused by tree species richness, by a more heterogeneous stand structure or both, we analyzed the effects of forest structure and tree species richness on stand productivity, based on inventory data of temperate forests in the United States of America and Germany.
Results: Having accounted for effects such as tree size and stand density, we found that: (I) tree species richness increased stand productivity in both countries while the effect of tree size heterogeneity on productivity was negative in Germany but positive in the USA; (II) productivity was highest at sites with an intermediate amount of precipitation; and (III) growth limitations due water scarcity or low temperature may enhance structural heterogeneity.
Conclusions: In the context of forest ecosystem goods and services, as well as future sustainable forest resource management, the associated implications would be:
Tree species richness is vital for maintaining forest productivity.
As an optimum amount of precipitation is accompanied by the highest productivity, changes in climatic
conditions should be considered when planning.
Resource limitations enhance structural heterogeneity, which in turn can have positive or negative effects on
stand productivity.
Furthermore, we discuss the difficulties encountered when analyzing different national forest inventories and large data sets
Paradigms in tropical forest plantations: a critical reflection on historical shifts in plantation approaches
Modeling Ecosystem Services for Park Trees : Sensitivity of i-Tree Eco Simulations to Light Exposure and Tree Species Classification
Ecosystem modeling can help decision making regarding planting of urban trees for climate change mitigation and air pollution reduction. Algorithms and models that link the properties of plant functional types, species groups, or single species to their impact on specific ecosystem services have been developed. However, these models require a considerable effort for initialization that is inherently related to uncertainties originating from the high diversity of plant species in urban areas. We therefore suggest a new automated method to be used with the i-Tree Eco model to derive light competition for individual trees and investigate the importance of this property. Since competition depends also on the species, which is difficult to determine from increasingly used remote sensing methodologies, we also investigate the impact of uncertain tree species classification on the ecosystem services by comparing a species-specific inventory determined by field observation with a genus-specific categorization and a model initialization for the dominant deciduous and evergreen species only. Our results show how the simulation of competition affects the determination of carbon sequestration, leaf area, and related ecosystem services and that the proposed method provides a tool for improving estimations. Misclassifications of tree species can lead to large deviations in estimates of ecosystem impacts, particularly concerning biogenic volatile compound emissions. In our test case, monoterpene emissions almost doubled and isoprene emissions decreased to less than 10% when species were estimated to belong only to either two groups instead of being determined by species or genus. It is discussed that this uncertainty of emission estimates propagates further uncertainty in the estimation of potential ozone formation. Overall, we show the importance of using an individual light competition approach and explicitly parameterizing all ecosystem functions at the species-specific level
World-Formation and Dasein
The subject of this paper is Heidegger's understanding of world and world-formation [Weltbildung] in his lecture The Fundamental Concepts of Metaphysics (GA 29/30) and his references to the idealistic philosophy of Schelling, such as the ancient thought of Aristotle and Heraclitus. I will put forward the following thesis: World is prevailing and, as this prevailing, it is the being of beings as such as whole in the projection of world that lets it prevail. In this paper, I will clarify how the world prevails, how Dasein forms the world, and the significance of physis, logos and as-structure in this context. I will also show that Heidegger's concept of world-formation, which is less discussed in research, can be thought together with his concepts of being-in-the-world and worldhood. Finally, I will discuss some of the difficulties of Heidegger's understanding of the world and propose some solutions
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