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Estimation of the mean tree height of forest stands by photogrammetric measurement using digital aerial images of high spatial resolution / Ivan Balenović in Annals of forest research, vol 58 n° 1 (January 2015)  

Public [article]  inAnnals of forest research > vol 58 n° 1 (January 2015) . - pp 125 - 143 Titre : Estimation of the mean tree height of forest stands by photogrammetric measurement using digital aerial images of high spatial resolution Type de document : Article/Communication Auteurs : Ivan Balenović, Auteur ; Ante Seletković, Auteur ; Renata Pernar, Auteur ; Anamarija Jazbec, Auteur Année de publication : 2015 Article en page(s) : pp 125 - 143 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] estimation quantitative [Termes IGN] hauteur des arbres [Termes IGN] image aérienne [Termes IGN] image infrarouge couleur [Termes IGN] pas d'échantillonnage au sol [Termes IGN] placette d'échantillonnage Résumé : (auteur) Tree height is one of the more fundamental measurements in forest inventories. In addition to classical field measurements, tree height may be estimated by remote sensing methods, such as by photogrammetric measurements of aerial images. Since it has been found and generally accepted that the extraction of forest and tree data from classical analogue aerial photographs has certain limitations, especially in the densely canopied forests, the usefulness of photogrammetric-based forest inventory in many countries remains a controversial issue. Therefore, this paper focuses on investigating the possibility of applying digital photogrammetric method to estimate mean stand height. Photogrammetric stereo-measurements of tree height were conducted on colour infrared images of high spatial resolution (ground sample distance – GSD – of 30 cm and 10 cm) using a digital photogrammetric workstation. The height of each tree within 183 sample plots (14 subcompartments) were calculated as the difference between the tree top elevations determined with the aerial images and the corresponding tree bottom elevations determined from the digital terrain model. To compare the photogrammetric- and field-estimated mean stand heights, the mean plot heights were calculated for both photogrammetric and field estimates of tree heights. Repeated measurements using ANOVA testing did not reveal a statistically significant difference (p > 0.05) between the field-estimated and photogrammetric-estimated mean stand heights using the 30 cm and 10 cm GSD digital aerial images. Deviations of the mean stand heights estimated using the images of both spatial resolutions were similar to the field-estimated heights. Using the 30 cm images the deviations of the photogrammetrically estimated mean stand height amounted to 0.35 m (1.59%) on average, whereas using the 10 cm images the deviations amounted to 0.31 m (1.41%) compared to the field estimation. Therefore, it can be concluded that the 30 cm GSD aerial images allow for the photogrammetric measurement of mean stand heights with accuracy similar to 10 cm GSD aerial images. In addition, 30 cm GSD aerial images are more favourable financially since the same area of interest could be covered with a considerably smaller number of images than of the 10 cm GSD aerial images. Numéro de notice : A2015-715 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.15287/afr.2015.300 En ligne : http://dx.doi.org/10.15287/afr.2015.300 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78358 [article]

Mapping the value of ecosystem services: A case study from the Austrian Alps / Alessandro Paletto in Annals of forest research, vol 58 n° 1 (January 2015)  

Public [article]  inAnnals of forest research > vol 58 n° 1 (January 2015) . - pp 157 - 175 Titre : Mapping the value of ecosystem services: A case study from the Austrian Alps Type de document : Article/Communication Auteurs : Alessandro Paletto, Auteur ; Clemens Geitner, Auteur ; Gianluca Grilli, Auteur ; Richard Hastik, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 157 - 175 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Economie [Termes IGN] aide à la décision [Termes IGN] alpes orientales [Termes IGN] Autriche [Termes IGN] carte thématique [Termes IGN] distribution spatiale [Termes IGN] forêt alpestre [Termes IGN] hétérogénéité spatiale [Termes IGN] indicateur de service écosystémique [Termes IGN] ressources naturelles [Termes IGN] service écosystémique [Termes IGN] valeur économique Résumé : (auteur) Ecosystem services (ES) are considered the conditions and processes through which natural ecosystems sustain and fulfil human life. In the decision making process related to the natural resources management, two key-aspects must be taken into account: the economic value of the benefits provided by ES (provisioning, regulating and cultural services) and the spatial distribution of these benefits. The purpose of the paper is to develop a method aimed to capture the economic value of the benefits provided by ES, in order to support the decision makers in the natural resources management. ES are not homogeneous across landscapes nor in space. Consequently, gaining knowledge on the spatial distribution of the economic relevance of ES is a fundamental information to target management actions. This method was tested in a case study in the Austrian Alps (Leiblachtal area in Vorarlberg region), characterized by a high importance of forests and grasslands. The results show that the highest economic values could be achieved for the provisioning services with a range between 200 €/ha year and 1,400€/ha year. The regulating services have also important economic values, but strongly localized in specific areas (i.e. protective forests against natural hazards). The economic values of the cultural services are influenced by the preferences of tourists and varies between 5 €/ha year to 60 €/ha year. The method allowed us to reveal the spatial heterogeneity of provisioning, regulating and cultural ES, depending on the ecological characteristics of the site. Numéro de notice : A2015-716 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.15287/afr.2015.335 En ligne : http://dx.doi.org/10.15287/afr.2015.335 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=78360 [article]