968 resultados para Agricultural and forest meteorology


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Microbial activity in soils is the main source of nitrous oxide (N2O) to the atmosphere. Nitrous oxide is a strong greenhouse gas in the troposphere and participates in ozone destructive reactions in the stratosphere. The constant increase in the atmospheric concentration, as well as uncertainties in the known sources and sinks of N2O underline the need to better understand the processes and pathways of N2O in terrestrial ecosystems. This study aimed at quantifying N2O emissions from soils in northern Europe and at investigating the processes and pathways of N2O from agricultural and forest ecosystems. Emissions were measured in forest ecosystems, agricultural soils and a landfill, using the soil gradient, chamber and eddy covariance methods. Processes responsible for N2O production, and the pathways of N2O from the soil to the atmosphere, were studied in the laboratory and in the field. These ecosystems were chosen for their potential importance to the national and global budget of N2O. Laboratory experiments with boreal agricultural soils revealed that N2O production increases drastically with soil moisture content, and that the contribution of the nitrification and denitrification processes to N2O emissions depends on soil type. Laboratory study with beech (Fagus sylvatica) seedlings demonstrated that trees can serve as conduits for N2O from the soil to the atmosphere. If this mechanism is important in forest ecosystems, the current emission estimates from forest soils may underestimate the total N2O emissions from forest ecosystems. Further field and laboratory studies are needed to evaluate the importance of this mechanism in forest ecosystems. The emissions of N2O from northern forest ecosystems and a municipal landfill were highly variable in time and space. The emissions of N2O from boreal upland forest soil were among the smallest reported in the world. Despite the low emission rates, the soil gradient method revealed a clear seasonal variation in N2O production. The organic topsoil was responsible for most of the N2O production and consumption in this forest soil. Emissions from the municipal landfill were one to two orders of magnitude higher than those from agricultural soils, which are the most important source of N2O to the atmosphere. Due to their small areal coverage, landfills only contribute minimally to national N2O emissions in Finland. The eddy covariance technique was demonstrated to be useful for measuring ecosystem-scale emissions of N2O in forest and landfill ecosystems. Overall, more measurements and integration between different measurement techniques are needed to capture the large variability in N2O emissions from natural and managed northern ecosystems.

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XVIII IUFRO World Congress, Ljubljana 1986.

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This paper reviews integrated economic and ecological models that address impacts and adaptation to climate change in the forest sector. Early economic model studies considered forests as one out of many possible impacts of climate change, while ecological model studies tended to limit the economic impacts to fixed price-assumptions. More recent studies include broader representations of both systems, but there are still few studies which can be regarded fully integrated. Full integration of ecological and economic models is needed to address forest management under climate change appropriately. The conclusion so far is that there are vast uncertainties about how climate change affects forests. This is partly due to the limited knowledge about the global implications of the social and economical adaptation to the effects of climate change on forests.

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Reducing emissions from deforestation and forest degradation (REDD+) is considered as an important mechanism under the UNFCCC aimed at mitigating climate change. The Cancun Agreement on REDD mechanism has paved the way for designing and implementation of REDD+ activities, to assist countries experiencing large-scale deforestation and forest degradation. Contrary to the general perception, the present analysis shows that India is currently experiencing deforestation and forest degradation. According to the latest assessment of the Forest Survey of India, the net annual loss of forests is estimated to be 99,850 ha during the period 2007-2009, even though the total area under forests has increased. The REDD+ mechanism aims to provide financial incentives for reducing deforestation and forest degradation. India, despite having robust legislations, policies and remote sensing capabilities, is not ready to benefit from the emerging REDD+ mechanism, with potential flow of large financial benefits to rural and forest-dependent communities from international financial sources.

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The agriculture, forestry and other land use (AFOLU) sector is responsible for approximately 25% of anthropogenic GHG emissions mainly from deforestation and agricultural emissions from livestock, soil and nutrient management. Mitigation from the sector is thus extremely important in meeting emission reduction targets. The sector offers a variety of cost-competitive mitigation options with most analyses indicating a decline in emissions largely due to decreasing deforestation rates. Sustainability criteria are needed to guide development and implementation of AFOLU mitigation measures with particular focus on multifunctional systems that allow the delivery of multiple services from land. It is striking that almost all of the positive and negative impacts, opportunities and barriers are context specific, precluding generic statements about which AFOLU mitigation measures have the greatest promise at a global scale. This finding underlines the importance of considering each mitigation strategy on a case-by-case basis, systemic effects when implementing mitigation options on the national scale, and suggests that policies need to be flexible enough to allow such assessments. National and international agricultural and forest (climate) policies have the potential to alter the opportunity costs of specific land uses in ways that increase opportunities or barriers for attaining climate change mitigation goals. Policies governing practices in agriculture and in forest conservation and management need to account for both effective mitigation and adaptation and can help to orient practices in agriculture and in forestry towards global sharing of innovative technologies for the efficient use of land resources. Different policy instruments, especially economic incentives and regulatory approaches, are currently being applied however, for its successful implementation it is critical to understand how land-use decisions are made and how new social, political and economic forces in the future will influence this process.

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Fire statistics (area burned) and fire-scar chronologies from tree rings show reduced fire activity during El Niño-Southern Oscillation (ENSO) in forests of Arizona and New Mexico. This relationship probably stems from increased fuel moisture after a wet winter and spring, but also could involve climatic controls on lightning activity at the onset of the monsoon season.

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In June, 1961, discussions were held in London to consider the future of the East Africa High Commission Services. It was agreed that the functions of the East Africa High Commission, with the exception of Defence, should be transfered to the East African Common Services Organization, which was subsequently established on 9th December, 1961, on the achievement of independence by Tanganyika. The Common Services Organization is controlled by an Authority, consisting of the principal elected Minister in each of the East African territories, which is responsible for the overall policy and direction of the Organization. The Authority is assisted by four Ministerial Committees, of which one is responsible for the Social and Research Services of the Organization

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The annual report present activities carried out by the different organizations that make up the East African Agricultural & Fisheries Research Council which covers reports from the following Organisations: I. Report of the East African Agriculture and Forestry Research Organization 2. Report of the East African Fishery Research Organization 3. Report of the East African Marine Fisheries Research Organization 4. Report of the East African Trypanosomiasis Research Organization 5. Report of the East African Veterinary Research Organization The activities reported are for the period 1958

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The annual report present activities carried out by the different organizations that make up the East African Agricultural & Fisheries Research Council which included: 1. Report of the East African Agriculture & Forestry Research Organization 2. Report of the East African Veterinary Research Organization 3. Report of the East African Fishery Research Organization 4. Report of the East African Marine Fisheries Research Organization The activities reported are for the period 1954-55.

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The annual report present activities carried out by the different organizations that make up the East African Agricultural & Fisheries Research Council which included: 1. Report of the East African Agriculture & Forestry Research Organization 2. Report of the East African Veterinary Research Organization 3. Report of the East African Fishery Research Organization 4. Report of the East African Marine Fisheries Research Organization and 5. Report of the East African Trypanosomiasis Research Organisation. The activities reported are for the period 1955-56.

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The annual report present activities carried out by the different organizations that make up the East African Agricultural & Fisheries Research Council which covers reports from the following Organisations: I. Report of the East African Agriculture and Forestry Research Organization 2. Report of the East African Fishery Research Organization 3. Report of the East African Marine Fisheries Research Organization 4. Report of the East African Trypanosomiasis Research Organization and 5. Report of the East African Veterinary Research Organization The activities reported are for the period 1956-57

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R. Zwiggelaar, C.R. Bull, and M.J. Mooney, 'X-ray simulations for imaging applications in the agricultural and food industry', Journal of Agricultural Engineering Research 63(2), 161-170 (1996)

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The possibility of encouraging the growth of forests as a means of sequestering carbon dioxide has received considerable attention, partly because of evidence that this can be a relatively inexpensive means of combating climate change. But how sensitive are such estimates to specific conditions? We examine the sensitivity of carbon sequestration costs to changes in critical factors, including the nature of management and deforestation regimes, silvicultural species, relative prices, and discount rates. (C) 2000 Academic Press.