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Prospects for quantifying structure, floristic composition and species richness of tropical forests / T.W. Gillespie in International Journal of Remote Sensing IJRS, vol 25 n° 4 (February 2004)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 25 n° 4 (February 2004) . - pp 707 - 715 Titre : Prospects for quantifying structure, floristic composition and species richness of tropical forests Type de document : Article/Communication Auteurs : T.W. Gillespie, Auteur ; J.C. Brock, Auteur ; C.W. Wright, Auteur Année de publication : 2004 Article en page(s) : pp 707 - 715 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] biodiversité [Termes IGN] canopée [Termes IGN] données lidar [Termes IGN] espèce végétale [Termes IGN] flore locale [Termes IGN] forêt tropicale Résumé : (Auteur) Airborne spectral and light detection and ranging (lidar) sensors have been used to quantify biophysical cahracteristics of tropical forests. Lidar sensors have provided high-resolution data on forest height, canopy topography, volume and gap size ; and provided estimates on number of strata in a forest, successional status of forests, and above-ground biomass. Spectral sensors have provided data on vegetation types, foliar biochemistry content of forest canopies, tree and canopy phenology, and spectral signatures for selected tree species. A number of advances are theorically possible with individual and combined spectral and lidar sensors for the study of forest structure, floristic composition and species richness. Delineating individual canopies of over-storey trees with small footprint lidar and discrimination of tree architectural types with waveform distributions is possible and would provide scientists with a new method to study tropical forest structure. Combined spectral and lidar data can be used to identify selected tree species and identify the successional status of tropical forest fragments in order to rank forest patches by levels of species richness. It should be possible in the near future to quantify selected patterns of tropical forests at a higher resolution than can currently be undertaken in the field or from space. Numéro de notice : A2004-073 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160310001598917 En ligne : https://doi.org/10.1080/01431160310001598917 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26601 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-04041	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

Improving tropical forest mapping using multi-date Landsat TM data and pre-classification image smoothing / C. Tottrup in International Journal of Remote Sensing IJRS, vol 25 n° 4 (February 2004)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 25 n° 4 (February 2004) . - pp 717 - 730 Titre : Improving tropical forest mapping using multi-date Landsat TM data and pre-classification image smoothing Type de document : Article/Communication Auteurs : C. Tottrup, Auteur Année de publication : 2004 Article en page(s) : pp 717 - 730 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] analyse diachronique [Termes IGN] canopée [Termes IGN] carte de la végétation [Termes IGN] classification par maximum de vraisemblance [Termes IGN] écosystème [Termes IGN] forêt tropicale [Termes IGN] image Landsat-TM [Termes IGN] image multitemporelle [Termes IGN] lissage de données Résumé : (Auteur) The present study explores the possibility of using Landsat imagery for mapping tropical forest types with relevance to forest ecosystem services. The central part in the classification process is the use of multi-date image data and pre-classification image smoothing. The study argues that multi-date imagery contains information on phenological and canopy structural properties and shows how the use of multi-date imagery has a significant impact on classification accuracy. Furthermore, the study shows the value of applying small kernel smoothing filters to reduce in-class spectral variability and enhance between-class spectral separability. Making use of these approaches and a maximum likehood algorithm, six tropical forest types were classified with an overall accuracy of 90.94%, and with individual forest classes mapped with accuracies above 75.19% (user's accuracy) and above 74.17% (producer accuracy). Numéro de notice : A2004-074 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160310001598926 En ligne : https://doi.org/10.1080/01431160310001598926 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26602 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-04041	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

Carbon mass fluxes of forests in Belgium determined with low resolution optical sensors / F. Veroustraete in International Journal of Remote Sensing IJRS, vol 25 n° 4 (February 2004)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 25 n° 4 (February 2004) . - pp 769 - 792 Titre : Carbon mass fluxes of forests in Belgium determined with low resolution optical sensors Type de document : Article/Communication Auteurs : F. Veroustraete, Auteur ; H. Sabbe, Auteur ; D.P. Rasse, Auteur ; L. Bertels, Auteur Année de publication : 2004 Article en page(s) : pp 769 - 792 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] Belgique [Termes IGN] bilan du carbone [Termes IGN] classificateur paramétrique [Termes IGN] corrélation [Termes IGN] covariance [Termes IGN] écosystème forestier [Termes IGN] forêt [Termes IGN] image NOAA-AVHRR [Termes IGN] image optique [Termes IGN] image SPOT-Végétation [Termes IGN] turbulence Résumé : (Auteur) The primary objective of this paper is to describe the validation of a parametric model (C-Fix) designed to estimate the basic carbon mass fluxes of forests in Belgium. Most validation efforts in the literature are based on point measurements. Since landscapes in Belgium are quite heterogeneous, the spatial up-scaling of a point measurement to the level of a sensor pixel is a crucial issue. Process based models quite often have a large set of input variables, some of them hardly available or not measurable on a regional basis; on the other hand most of the process based models possess a prognostic capacity. The parametric C-Fix model estimates carbon mass fluxes from local, regional to continental scales. It ingests only a modest number of meteorological input variables, including satellite observations. Parametric models do not possess a prognostic capacity, but the spatial up-scaling by the use of remote sensing data is much more straightforward than with process models. In this paper, we describe the validation of C-Fix with eddy covariance NEP (net ecosystem production) measurements and further applied C-Fix for the mapping of the geographical distribution of carbon mass fluxes over the entire Belgian territory, using NOAA-AVHRR (1997) and SPOT4-VGT imagery (April 1998-March 1999). We combine a forest probability map, derived from NOAA data for 1997 with the mapped estimates of Belgian NEP to obtain forest NEP per image pixel. Forest NEP is validated regionally, with measurements of carbon exchange obtained at two Belgian Euroflux eddy covariance tower sites (the Brasschaat, 'Inslag' and Vielsalm, 'Tinscubois' forest sites). A correlation analysis is performed for the estimated forest NEPs at both Euroflux sites and the NEP measured there, assumed to be primarily from forest. Finally, a correlation analysis with a process-based stand scale model (ASPECTS) is performed for the two forest sites, as a cross cheek on the validation results. Our results demonstrate that a parametric model, like C-Fix, provides a good basis to estimate the evolution and geographical distribution of the main constituents of the carbon budget of terrestrial ecosystems, in this study specifically forest ecosystems at the regional scale (Belgium). Numéro de notice : A2004-075 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000115238 En ligne : https://doi.org/10.1080/0143116031000115238 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26603 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-04041	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

Estimating fragmentation effects on simulated forest net primary productivity derived from satellite imagery / Nicholas C. Coops in International Journal of Remote Sensing IJRS, vol 25 n° 4 (February 2004)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 25 n° 4 (February 2004) Titre : Estimating fragmentation effects on simulated forest net primary productivity derived from satellite imagery Type de document : Article/Communication Auteurs : Nicholas C. Coops, Auteur ; J.D. White, Auteur ; N.A. Scott, Auteur Année de publication : 2004 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] canopée [Termes IGN] carbone [Termes IGN] écosystème forestier [Termes IGN] forêt [Termes IGN] image multibande [Termes IGN] image SPOT-Végétation [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] Nouvelle-Zélande [Termes IGN] production primaire nette Résumé : (Auteur) Conversion of native forests to agriculture and urban land leads to fragmentation of forested landscapes with significant consequences for habitat conservation and forest productivity. When quantifying land-cover patterns from airborne or spaceborne sensors, the interconnectedness of fragmented landscapes may vary depending on the spatial resolution of the sensor and the extent at which the landscape is being observed. This scale dependence can significantly affect calculation of remote sensing vegetation indices, such as the Normalized Difference Vegetation Index (NDVI) and its subsequent use to predict biophysical parameters such as the fraction of photosynthetically active radiation intercepted by forest canopies (fPAR). This means that simulated above-ground net primary productivity (NPPA) using canopy radiation interception models such as 3-PG (Physiological Principles for Predicting Growth), coupled with remote sensing observations, can yield different results in fragmented landscapes depending on the spatial resolution of the remotely sensed data. We compared the amount of forest fragmentation in 1 km SPOT-4 VEGETATION pixels using a simultaneously acquired 20m SPOT-4 multispectral (XS) image. We then predicted NPPA for New Zealand native forest ecosystems using the 3-PG model with satellite-derived estimates of the WAR obtained from the SPOT-4 VEGETATION sensor, using NDVI values with and without correction for fragmentation. We examined three methods to correct for sub-pixel fragmentation effects on NPPA. These included: (1) a simple conversion between the broad 1 km scale NDVI values and the XS NDVI values; (2) utilisation of contextural information from XS NDVI pixels to derive a single coefficient to adjust the 1 km NDVI values; and (3) calculation of the degree of fragmentation within each VEGETATION 1 km pixel and reduce NDVI by an empirically derived amount based on the proportional areal coverage of forest in each pixel. Our results indicate that predicted NPPA derived from uncorrected 1 km VEGETATION pixels was significantly higher than estimates using adjusted NDVI values; all three methods reduced the predicted NPPA. In areas of the landscape with a large degree of forest defragmentation (such as forest boundaries) predictions of NPPa indicate that the fragmentation effect has implications for spatially extensive estimates of carbon uptake by forests. Numéro de notice : A2004-076 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000115094 En ligne : https://doi.org/10.1080/0143116031000115094 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26604 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-04041	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt