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Assessing structural complexity of individual scots pine trees by comparing terrestrial laser scanning and photogrammetric point clouds / Noora Tienaho in Forests, Vol 13 n° 8 (August 2022)  

Public [article]  inForests > Vol 13 n° 8 (August 2022) . - n° 1305 Titre : Assessing structural complexity of individual scots pine trees by comparing terrestrial laser scanning and photogrammetric point clouds Type de document : Article/Communication Auteurs : Noora Tienaho, Auteur ; Tuomas Yrttimaa, Auteur ; Ville Kankare, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 1305 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications photogrammétriques [Termes IGN] analyse comparative [Termes IGN] Finlande [Termes IGN] hauteur des arbres [Termes IGN] image captée par drone [Termes IGN] photogrammétrie aérienne [Termes IGN] Pinus sylvestris [Termes IGN] semis de points [Termes IGN] structure d'un peuplement forestier [Termes IGN] structure-from-motion [Termes IGN] télémétrie laser terrestre Résumé : (auteur) Structural complexity of trees is related to various ecological processes and ecosystem services. To support management for complexity, there is a need to assess the level of structural complexity objectively. The fractal-based box dimension (Db) provides a holistic measure of the structural complexity of individual trees. This study aimed to compare the structural complexity of Scots pine (Pinus sylvestris L.) trees assessed with Db that was generated with point cloud data from terrestrial laser scanning (TLS) and aerial imagery acquired with an unmanned aerial vehicle (UAV). UAV imagery was converted into point clouds with structure from motion (SfM) and dense matching techniques. TLS and UAV measured Db-values were found to differ from each other significantly (TLS: 1.51 ± 0.11, UAV: 1.59 ± 0.15). UAV measured Db-values were 5% higher, and the range was wider (TLS: 0.81–1.81, UAV: 0.23–1.88). The divergence between TLS and UAV measurements was found to be explained by the differences in the number and distribution of the points and the differences in the estimated tree heights and number of boxes in the Db-method. The average point density was 15 times higher with TLS than with UAV (TLS: 494,000, UAV 32,000 points/tree), and TLS received more points below the midpoint of tree heights (65% below, 35% above), while UAV did the opposite (22% below, 78% above). Compared to the field measurements, UAV underestimated tree heights more than TLS (TLS: 34 cm, UAV: 54 cm), resulting in more boxes of Db-method being needed (4–64%, depending on the box size). Forest structure (two thinning intensities, three thinning types, and a control group) significantly affected the variation of both TLS and UAV measured Db-values. Still, the divergence between the two approaches remained in all treatments. However, TLS and UAV measured Db-values were consistent, and the correlation between them was 75%. Numéro de notice : A2022-652 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.3390/f13081305 Date de publication en ligne : 16/08/2022 En ligne : https://doi.org/10.3390/f13081305 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101499 [article]

Influence of the declaration of protected natural areas on the evolution of forest fires in collective lands in Galicia (Spain) / Gervasio Lopez Rodriguez in Forests, Vol 13 n° 8 (August 2022)  

Public [article]  inForests > Vol 13 n° 8 (August 2022) . - n° 1161 Titre : Influence of the declaration of protected natural areas on the evolution of forest fires in collective lands in Galicia (Spain) Type de document : Article/Communication Auteurs : Gervasio Lopez Rodriguez, Auteur ; Veronica Rodriguez vicente, Auteur ; Manuel F. Marey-Pérez, Auteur Année de publication : 2022 Article en page(s) : n° 1161 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse diachronique [Termes IGN] Eucalyptus globulus [Termes IGN] forêt privée [Termes IGN] Galice (Espagne) [Termes IGN] incendie de forêt [Termes IGN] Pinus pinaster [Termes IGN] protection des forêts [Termes IGN] Quercus pedunculata [Termes IGN] site Natura 2000 [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) Since the adoption of European Union Council Directive 92/43 on the conservation of natural habitats and wild fauna and flora, some opposition has arisen among owners and managers of land affected by the directive. Some studies have indicated that some of this opposition has found expression in subsequent arson fires in these areas. This article analyses the occurrence of arson fires in the SACs (Special Areas of Conservation) included in the European ecological network, Natura 2000, in Galicia (Spain), more specifically in the montes vecinales en mano común (MVMCs), which are privately owned collective lands. We tested whether the declaration of SACs had a statistical impact on the forest fire regime in the period 1999–2014. The analyses focused on the sub-periods of 1999–2004 and 2005–2014, i.e., before and after the approval of the list of sites of community importance in the study area in December 2004. The results obtained show that, after the declaration of protection, there was a statistically significant increase in the area burnt by fire in these areas, mainly on private estates. We also found that the percentage of arson fires after 2004 was higher in SACs than in other territorial units. We found that the percentage of arson fires was reduced less in SACs than in other territorial units. Furthermore, we found that the area burnt per fire after 2004 in SACs was almost double that in the MVMC-SACs (12.04 ha versus 6.64 ha), so it can be concluded that the conservationist policies of the Natura 2000 network in Galicia have not had a positive effect on the forest fire regime. Numéro de notice : A2022-653 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.3390/f13081161 Date de publication en ligne : 22/07/2022 En ligne : https://doi.org/10.3390/f13081161 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101501 [article]

Remote sensing and phytoecological methods for mapping and assessing potential ecosystem services of the Ouled Hannèche Forest in the Hodna Mountains, Algeria / Amal Louail in Forests, Vol 13 n° 8 (August 2022)  

Public [article]  inForests > Vol 13 n° 8 (August 2022) . - n° 1159 Titre : Remote sensing and phytoecological methods for mapping and assessing potential ecosystem services of the Ouled Hannèche Forest in the Hodna Mountains, Algeria Type de document : Article/Communication Auteurs : Amal Louail, Auteur ; François Messner, Auteur ; Yamna Djellouli, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 1159 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] Algérie [Termes IGN] analyse multicritère [Termes IGN] carte thématique [Termes IGN] entropie de Shannon [Termes IGN] forêt méditerranéenne [Termes IGN] image Landsat-8 [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] protection de la biodiversité [Termes IGN] relevé phytoécologique [Termes IGN] service écosystémique Résumé : (auteur) Regardless of their biogeographic origins or degree of artificialization, the world’s forests are a source of a wide range of ecosystem services (ES). However, the quality and quantity of these services depend on the type of forest studied and its phytogeographic context. Our objective is to transpose the concept of ES, in particular, the assessment of forest ES, to the specific Mediterranean context of the North African mountains, where this issue is still in its infancy and where access to the data needed for assessment remains difficult. Our work presents an introductory approach, allowing us to set up methodological and scientific milestones based on open-access remote sensing data and already tested geospatial processing associated with phytoecological surveys to assess the ES provided by forests in an Algerian study area. Specifically, several indicators used to assess (both qualitatively and quantitatively) the potential ES of the Ouled Hannèche forest, a forest located in the Hodna Mountains, are derived from LANDSAT 8 OLI images from 2017 and an ALOS AW3D30 DSM. The qualitative ES typology is jointly based on an SVM classification of topographically corrected LANDSAT images and a geomorphic-type classification using the geomorphon method. NDVI is a quantitative estimator of many plant ecosystem functions related to ES. It highlights the variations in the provision of ES according to the types of vegetation formations present. It serves as a support for estimating spectral heterogeneity through Rao’s quadratic entropy, which is considered a relative indicator of biodiversity at the landscape scale. The two previous variables (the multitemporal NDVI and Rao’s Q), completed by the Shannon entropy method applied to the geomorphon classes as a proxy for topo-morphological heterogeneity, constitute the input variables of a quantitative map of the potential supply of ES in the forest determined by Spatial Multicriteria Analysis (SMCA). Ultimately, our results serve as a useful basis for land-use planning and biodiversity conservation. Numéro de notice : A2022-654 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.3390/f13081159 Date de publication en ligne : 22/07/2022 En ligne : https://doi.org/10.3390/f13081159 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101502 [article]