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Book (stand-alone)USE OF NOAA REMOTE SENSING DATA FOR ASSESSMENT OF THE FOREST AREA OF LIBERIA 1993
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No results found.In the context of developing a practicable and cost effective method for obtaining a country’s forest area by remote sensing, the computer processing of NOAA AVHRR HRPT data covering Liberia was investigated. The only cloud-free scene then recorded turned out to be severely and unevenly affected by atmospheric haze. To mitigate the effects of this, the country was divided into six areas (strata) of more uniform haze conditions. Pixel DN values were obtained for forest and adjoining formations on transects within each stratum, for the first four AVHRR channels and three transforms: NDVI (2-1/2 + 1), IND3 (3-2/3 + 2), IND4(4-2/4 + 2). After analyzing the transects and comparing them with the available reference data (a mixture of large scale colour composite Landsat TM and MSS images for 1989 and 1986 respectively), channels 2, 3, 4 and IND3 were retained for processing. This was done by applying three methods to each stratum - thresholding, maximum likelihood classification using cluste ring signatures (hybrid), m.l.c. using training area signatures - and directed at separating the 5 main classes distinguishable on the Landsat images: Closed forest, Disturbed forest, Shifting cultivation and regrowth, Cultivation and Other. -
ProjectForest resources mapping of Liberia 1986
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No results found.This report covers the work of forest resources mapping undertaken by the Remote Sensing Unit of the Forestry Development Authority of Liberia between March 1982 and June 1984. Its principle aim is to reassess the actual forest cover area of Liberia by interpretation of recent aerial photography and the subsequent transfer of this photo detail to 1 in 125,000 map series. The procedures adopted for this mapping study are detailed. In conjunction with this work a deforestation study was also carri ed out using the same selected areas from each of the 1953, 1969 and 1979/82 aerial photography series. The results of these studies are discussed and related to previous estimates that have been made. The results include information about forest areas (by forest type and in three slope classes). -
Book (stand-alone)The world's mangroves 1980-2005 2007
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No results found.Mangroves, commonly found along sheltered coastlines in the tropics and subropics, fulfil important socio-economic and envioronmental functions: providing wood and non-wood forest products, protecting shores against wind, waves and water currents; conserving biological diversity; protecting coral reefs, sea-grass beds and shipping lanes against siltation; and providing habitat, spawning grounds and nutrients for a variety of fish and shellfish, including many commercial species. High population pressure in coastal areas has, however, led to the conversion of many mangrove areas to other uses. The world's mangroves 1980-2005, prepared in the framework of the Global Forest Resources Assessment 2005, provides comprehensive information on the current and past extent of mangroves in all countries and territories in which they exist. This information, as well as the gaps in information that come to light in the report, will assist mangrove managers and policy- and decision-makers worldwide i n ensuring the conservation, management and sustainable use of the world's remaining mangrove ecosystems.
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