222 research outputs found

    Forest vegetation management: France (chap.4)

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    Current practices and problems of forest vegetation management in France are described in the context of research on alternatives to herbicides.FORET;PEUPLEMENT FORESTIER;VEGETATION;CONCURRENCE VEGETALE;LUTTE;MODE DE TRAITEMENT;LUTTE PHYTOSANITAIRE + MAUVAISE HERBE;CONTROLE DE LA VEGETATION;PESTICIDE;HERBICIDE;LUTTE PHYTOSANITAIRE;IMPACT SUR L'ENVIRONNEMENT;DYNAMIQUE DE VEGETATION;HISTOIRE;GESTION FORESTIERE;ECOSYSTEME;FRANCE;VEGETATION FORESTIERE;GESTION;ALTERNATIVES AUX HERBICIDES;ADVENTICE;SPECIES COMPOSITION

    Quelle sylviculture des peuplements mélangés ? Restitution de l'atelier 3

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    L'article donne le compte-rendu condensĂ© de l'atelier de discussion sur les peuplements mĂ©langĂ©s qui a eu lieu dans le cadre du colloque "forĂȘts mĂ©langĂ©es : quels scĂ©narios pour l'avenir ?" / The article reports briefly discussions that took place during the workshop on "mixed stands: which scenarios for future?"PEUPLEMENT MELANGE;SYLVICULTURE;REGENERATION DES ARBRES;CONDUITE DU PEUPLEMENT;REFERENCE TECHNICO ECONOMIQUE;FAGUS SYLVATICA;QUERCUS PETRAEA;PEUPLEMENT EQUIENNE;PEUPLEMENT INEQUIENNE;BESOIN EN EAU;LUMIERE;CONCURRENCE VEGETALE;COUT;COMPETITION

    Forest vegetation management in Europe: current practice and future requirements

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    The book provides a record of the co-operation within Europe in the field of forest vegetation management through the Cost Action E47. The aims are: i)to provide a summary of the current state of the art' as it applies to forest vegetation management in Europe for scientists, practitioners and policymakers, affiliated to state, non-governmental or private commercial organizations; ii)to document existing forest weed control practices across Europe, and hence provide a resource of alternative solutions for individual countries sharing similar conditions and challenges; and iii)to identify common information gaps and future research needs, and hence potential future areas of collaboration for forest vegetation management scientists across Europe, along with barriers that may need to be overcome to achieve that aim.FORET;PEUPLEMENT FORESTIER;VEGETATION;CONCURRENCE VEGETALE;LUTTE;MODE DE TRAITEMENT;COOPERATION INTERNATIONALE;RECHERCHE DEVELOPPEMENT;DEVELOPPEMENT DURABLE;AMENAGEMENT FORESTIER;MAUVAISE HERBE;CONTROLE DE LA VEGETATION;PESTICIDE;LUTTE PHYTOSANITAIRE;IMPACT SUR L'ENVIRONNEMENT;DYNAMIQUE DE VEGETATION;HERBICIDE;BIODIVERSITE;ECOSYSTEME;HISTOIRE;GESTION FORESTIERE;EUROPE;VEGETATION FORESTIERE;ADVENTICE;ALTERNATIVES AUX HERBICIDES;

    Predicting understory maximum shrubs cover using altitude and overstory basal area in different Mediterranean forests

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    In some areas of the Mediterranean basin where the understory stratum represents a critical fire hazard, managing the canopy cover to control the understory shrubby vegetation is an ecological alternative to the current mechanical management techniques. In this study, we determine the relationship between the overstory basal area and the cover of the understory shrubby vegetation for different dominant canopy species (Pinaceae and Fagaceae species) along a wide altitudinal gradient in the province of Catalonia (Spain). Analyses were conducted using data from the Spanish National Forest Inventory. At the regional scale, when all stands are analysed together, a strong negative relationship between mean shrub cover and site elevation was found. Among the Pinaceae species, we found fairly good relationships between stand basal area and the maximum development of the shrub stratum for species located at intermediate elevations (Pinus nigra, Pinus sylvestris). However, at the extremes of the elevationclimatic gradient (Pinus halepensis and Pinus uncinata stands), stand basal area explained very little of the shrub cover variation probably because microsite and topographic factors override its effect. Among the Fagaceae species, a negative relationship between basal area and the maximum development of the shrub stratum was found in Quercus humilis and Fagus sylvatica dominated stands but not in Quercus ilex. This can be due to the particular canopy structure and management history of Q. ilex stands. In conclusion, our study revealed a marked effect of the tree layer composition and the environment on the relationship between the development of the understory and overstory tree structure. More fine-grained studies are needed to provide forest managers with more detailed information about the relationship between these two forest strata

    Territorial rights and colonial wrongs

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    What is wrong with colonialism? The standard—albeit often implicit—answer to this question has been that colonialism was wrong because it violated the territorial rights of indigenous peoples, where territorial rights were grounded on acquisition theories. Recently, the standard view has come under attack: according to critics, acquisition based accounts do not provide solid theoretical grounds to condemn colonial relations. Indeed, historically they were used to justify colonialism. Various alternative accounts of the wrong of colonialism have been developed. According to some, colonialism involved a violation of territorial rights grounded on legitimate state theory. Others reject all explanations of colonialism's wrongfulness based on territorial rights, and argue that colonial practices were wrong because they departed from ideals of economic, social, and political association. In this article, we articulate and defend the standard view against critics: colonialism involved a procedural wrong; this wrong is not the violation of standards of equality and reciprocity, but the violation of territorial rights; and the best foundation for such territorial rights is acquisition based, not legitimacy based. We argue that this issue is not just of historical interest, it has relevant implications for the normative evaluation of contemporary inequalities

    A global analysis of the comparability of winter chill models for fruit and nut trees

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    Many fruit and nut trees must fulfill a chilling requirement to break their winter dormancy and resume normal growth in spring. Several models exist for quantifying winter chill, and growers and researchers often tacitly assume that the choice of model is not important and estimates of species chilling requirements are valid across growing regions. To test this assumption, Safe Winter Chill (the amount of winter chill that is exceeded in 90% of years) was calculated for 5,078 weather stations around the world, using the Dynamic Model [in Chill Portions (CP)], the Chilling Hours (CH) Model and the Utah Model [Utah Chill Units (UCU)]. Distributions of the ratios between different winter chill metrics were mapped on a global scale. These ratios should be constant if the models were strictly proportional. Ratios between winter chill metrics varied substantially, with the CH/CP ratio ranging between 0 and 34, the UCU/CP ratio between −155 and +20 and the UCU/CH ratio between −10 and +5. The models are thus not proportional, and chilling requirements determined in a given location may not be valid elsewhere. The Utah Model produced negative winter chill totals in many Subtropical regions, where it does not seem to be useful. Mean annual temperature and daily temperature range influenced all winter chill ratios, but explained only between 12 and 27% of the variation. Data on chilling requirements should always be amended with information on the location and experimental conditions of the study in which they were determined, ideally including site-specific conversion factors between winter chill models. This would greatly facilitate the transfer of such information across growing regions, and help prepare growers for the impact of climate change

    A roupa nova do presidente: a politização da imagem pĂșblica de JĂąnio Quadros (1947-1961)

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    JĂąnio Quadros public image is often considered deprived of any political meaning either by historians or by collective memory. In most cases he is treated as a demagogue who promoted himself only through his personalism, which could be seen in his public appearances unkempt and with open-necked shirts. Such perspective is deeply related to the way his opponents and enemies represented him in the political debates, and its core has been successful in penetrating the historiography. However in this text I intend to suggest that JĂąnio's images conveyed an array of political senses during the 1950s and early 1960s, since the beginning of his career till when he disputed presidential elections and ruled Brazil as president. Through his gestures and clothes, among which his Indian slacks deserve more attention, he tried to express his project related to the Christian Democracy and the Independent Foreign Policy. To deal with such hypothesis, the main sources will be the magazines O Cruzeiro and Manchete and others photos and drawings that were considerably widespread at that time.A imagem pĂșblica de JĂąnio Quadros Ă© frequentemente considerada como desprovida de quaisquer significados polĂ­ticos, seja por historiadores ou pela memĂłria coletiva. Na maioria dos casos, ele Ă© tratado como um demagogo que se promovia apenas atravĂ©s de seu personalismo, exibindo-se em suas apariçÔes pĂșblicas despenteado e com camisas abertas no colarinho. Tal perspectiva estĂĄ profundamente relacionada com a forma pela qual seus oponentes e inimigos o representavam nos debates polĂ­ticos, e em seu cerne foi bem-sucedida, tendo penetrado na historiografia. Neste texto, porĂ©m, pretendo sugerir que, perpassando a dĂ©cada de 1950 e o inĂ­cio da de 1960, desde o inĂ­cio de sua carreira atĂ© o momento em que disputou eleiçÔes presidenciais e foi o presidente do Brasil, as imagens de JĂąnio veiculavam um amplo leque de sentidos polĂ­ticos. Por meio de gestos e roupas, destacando-se aĂ­ seus slacks indianos, ele procurou expressar seus projetos relacionados Ă  Democracia CristĂŁ e Ă  PolĂ­tica Externa Independente. Para lidar com essa hipĂłtese, as principais fontes fotogrĂĄficas e textuais elencadas sĂŁo as revistas O Cruzeiro e Manchete da Ă©poca, e outras fotos e ilustraçÔes que entĂŁo foram bastante difundidas
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