268 research outputs found

    Fuelwood demand and supply in Rwanda and the role of agroforestry

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    Fuelwood in Rwanda is assumed to come from forests and woodlands, thus contributing to large-scale deforestation. Available studies on fuelwood demand and supply support this assumption and indicate a continuously rising demand of fuelwood, notably from forest plantations. These assertions are insufficiently substantiated as existing forest stock may not be depleted by rapid increase in demand for food and energy resources resulting from population growth, but rather from the need for agricultural land. Evidence suggests that the demands for fuelwood, in addition to other sources of energy, is supplied from agroforestry systems which has not been quantified so far. This review analyses sources and use of fuelwood in Rwanda, indicating the importance of on-farms trees and woodlots in fuelwood supply. It is concluded that the effect of fuelwood consumption on land use is difficult to disentangle as many other factors including land clearing for agriculture, livestock farming, human settlements, illegal cutting of valuable timber species, the demand for charcoal in towns and past conflicts, contributed significantly to the high rate of deforestation in the country. If fuelwood demand is to be met on a sustainable basis, more fuelwood has to be produced on agricultural lands and in forest plantations through species site matching and proper management

    Oak Persistence in Mediterranean Landscapes: The Combined Role of Management, Topography, and Wildfires

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    Mediterranean ecosystems have been shaped by a history of human and ecological disturbances. Understanding the dynamics of these social-ecological systems requires an understanding of how human and ecological factors interact. In this study, we assess the combined role of management practices and biophysical variables, i.e., wildfire and topography, to explain patterns of tree persistence in a cork oak (Quercus suber L.) landscape of southern Portugal. We used face-to-face interviews with landowners to identify the management practices and the incentives that motivated them. We used aerial photographs and a Geographic Information System (GIS) to classify vegetation patch-type transitions over a period of 45 years (1958-2002) and logistic regression to explain such changes based on management and biophysical factors. The best model explaining vegetation transitions leading to cork oak persistence in the landscape included both biophysical and management variables. Tree persistence was more likely to occur on steeper slopes, in the absence of wildfires, and in the absence of understory management. We identified ecological, ideological, and economical barriers that preclude oak persistence and that are important to consider in implementing efficient environmental policies for adequate conservation and reforestation programs of Mediterranean cork oak landscape

    Bepaal zelf de koolstofvastlegging in je bos

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    Attendering op het model CO2FIX ter bepaling van de koolstofvastleggin

    Bos in weer en wind

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    Are drought and wildfires turning Mediterranean cork oak forests into persistent shrublands?

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    In the Iberian Peninsula Mediterranean oak forests have been transformed into a mosaic landscape of four main patch-types: forests, savannas, shrublands and grasslands. We used aerial photographs over a period of 45 years (1958-2002) to quantify the persistence and rates of transitions between vegetation patch-types in southern Portugal, where cork oak is the dominant tree species. We used logistic regression to relate vegetation changes with topographical features and wildfire history. Over the 45 years, shrublands have been the most persistent patch-type (59%), and have been expanding; forests are also persistent (55%) but have been decreasing since 1985; savannas and grasslands were less persistent (33% and 15%, respectively). Shrublands persistence was significantly correlated with wildfire occurrence, particularly on southern exposures after 1995. In contrast, forest persistence decreased with wildfire occurrence, and forests were more likely to change into shrublands where wildfire had occurred after 1995

    Koninklijke Nederlandse Bosbouwvereniging: van bosbouw naar bosbeheer

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    Bos en bosbeheer veranderen continu. Met de ontwikkeling van de productiegerichte bosbouw van vijftig jaar geleden naar een bosbeheer gericht op meervoudige functievervulling in een dichtbevolkte samenleving veranderde ook de rol van de beheerder. Dit vraagt om andere kennis en vaardigheden van de beroepsgroep en andere organisatievormen van onderwijs en onderzoek. De Koninklijke Nederlandse Bosbouw Vereniging (KNBV) fungeert sinds de oprichting in 1910 als vakvereniging door en voor mensen uit de sector, volledig draaiend op vrijwilligers. De veranderingen in de sector en het werkveld vragen ook om een andere rol van de beroepsvereniging
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