Abstract:Lack of reliable and up-to-date maps relating to land cover (among other themes) constitute a weakness in land resource surveys and cause costly failures to many forest rehabilitation projects in the tropics. This study evaluated the utility of satellite imagery for land cover mapping for forest rehabilitation planning in a case study in Mindoro, Philippines. Using Landsat TM data, visual and digital image processing techniques were performed using the GRID module of ARC/INFO and the microBRIAN image processin… Show more
“…Within forest management, these data are required to assess the volume of timber available within potential harvesting coupes (MacLean and Krabill, 1986;Jusoff and Souza, 1996;Trotter et al, 1997). Within tropical rain forests already disturbed by selective felling, forestry organizations need to quantify the rate of biomass recovery to judge the impact of previous operations and the timing of the next phase of selective logging (Pinard and Putz, 1996;Apan, 1997;Asner et al, 2002). Assessments of impacts of forest disturbance and rehabilitation on carbon sequestration (Chambers et al, 2007;Saatchi et al, 2007), would similarly benefit from regional biomass estimates.…”
“…Within forest management, these data are required to assess the volume of timber available within potential harvesting coupes (MacLean and Krabill, 1986;Jusoff and Souza, 1996;Trotter et al, 1997). Within tropical rain forests already disturbed by selective felling, forestry organizations need to quantify the rate of biomass recovery to judge the impact of previous operations and the timing of the next phase of selective logging (Pinard and Putz, 1996;Apan, 1997;Asner et al, 2002). Assessments of impacts of forest disturbance and rehabilitation on carbon sequestration (Chambers et al, 2007;Saatchi et al, 2007), would similarly benefit from regional biomass estimates.…”
“…Singh, 1987;Apan, 1997). The contrasting reflectance properties of these two land use/cover classes in the visible and infrared bands allow their easy differentiation using digital approaches.…”
Section: Mapping and Landscape Metrics Calculationsmentioning
A case study of the Lockyer Valley catchment in Queensland, Australia, was conducted to develop appropriate mapping and assessment techniques to quantify the nature and magnitude of riparian landscape structural changes within a catchment. The study employed digital image processing techniques to produce land cover maps from the 1973 and 1997 Landsat imagery. Fixed and variable width buffering of streams were implemented using a geographic information system (GIS) to estimate the riparian zone and to subsequently calculate the landscape patterns using the Patch Analyst (Grid) program (a FRAGSTATS interface). The nature of vegetation clearing was characterised based on land tenure, slope and stream order. Using the Pearson chi-square test and Cramer's V statistic, the relationships between the vegetation clearing and land tenure were further assessed. The results show the significant decrease in woody vegetation areas mainly due to conversion to pasture. Riparian vegetation corridors have become more fragmented, isolated and of much smaller patches. Land tenure was found to be significantly associated with the vegetation clearing, although the strength of association was weak. The large proportion of deforested riparian zones within steep slopes or first-order streams raises serious questions about the catchment health and the longer term potential for land degradation by upland clearing. This study highlights the use of satellite imagery and geographic information systems in mapping and analysis of landscape structural change, as well as the identification of key issues related to sensor spatial resolution, stream buffering widths, and the quantification of land transformation processes.
“…El autor Apan (1997) ha estudiado bosques tropicales complejos con una fiabilidad de 66,7 % para el usuario y 56,6 % para el productor. Por su parte, Liberti et al (2009) discriminan bosques con una precisión global entre 53 % a 72 %.…”
SUMMARYAraucaria forests (Araucaria araucana) have a tremendous ecological relevance; however, the information concerning their spatial distribution is still insufficient. They have only been classified according to small management scales, using satellite photos and images processed through conventional methods. The present study had as its objective to discriminate and characterize types of A. araucana forests in the Conguillío National Park, located in the Southern-Center Chile, through data derived from the Landsat-5 TM satellite and geographic information systems. The normalized difference vegetation index (NDVI) was satisfactorily related with variables corresponding to crown coverage and the diameter at breast height; thus, these index values were incorporated to the classification process. Using the digital elevation model and the NDVI, the effect provoked by the shadow was minimized. Seven types of forests, between dense and semi-dense-open, were discriminated in accordance with the accompanying species. The global reliability of the classification was 83.8 %. The greatest reliability for the producer was for the medium crown density forest of A. araucana -N. dombeyi (B1) (87.5 %); and for the consumer, for the high crown density forests of A. araucana -N. dombeyi (B1) and also for those of medium density (B2) (93 %). It is concluded that incorporating NDVI values and data derived from the digital elevation model to the satellite classification process, it is possible to discriminate araucaria forests with satisfactory reliability in areas of rough relief, which is very useful information for the management of these forestry ecosystems.
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