Détail de l'autorité
|
Conference 2019, A century of national forest inventories – informing past, present and future decisions 19/05/2019 21/05/2019 Oslo Norvège programme sans actes
nom du congrès :
Conference 2019, A century of national forest inventories – informing past, present and future decisions
début du congrès :
19/05/2019
fin du congrès :
21/05/2019
ville du congrès :
Oslo
pays du congrès :
Norvège
site des actes du congrès :
|
Documents disponibles (5)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externesBiomass ratio varies along soil water availability : An analysis based on wood density data collected by the French NFI / Baptiste Kerfriden (2019)
Titre : Biomass ratio varies along soil water availability : An analysis based on wood density data collected by the French NFI Type de document : Article/Communication Auteurs : Baptiste Kerfriden , Auteur ; Jean-Daniel Bontemps
Editeur : Paris [France] : Institut national de recherche pour l’agriculture, l’alimentation et l’environnement INRAE (2020-) Année de publication : 2019 Conférence : Conference 2019, A century of national forest inventories – informing past, present and future decisions 19/05/2019 21/05/2019 Oslo Norvège programme sans actes Langues : Anglais (eng) Descripteur : [Termes IGN] biomasse forestière
[Termes IGN] changement climatique
[Termes IGN] composition d'un peuplement forestier
[Termes IGN] densité du bois
[Termes IGN] humidité du sol
[Termes IGN] inventaire forestier national (données France)
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) Biomass ratio is a state variable allowing the conversion of the forest growing stock into biomass (Kauppi et al., 2006). This variable is most often considered constant per tree species despite the huge range of intraspecific variability of basic density. Indeed, the factors that influence wood density are numerous: tree growth and age, competition (e.g. forest structure), genetics as well as intra and inter annual climatic variations. In light of such diversity, scientific research into forest biomass characteristics is required to better incorporate the heterogeneity of forests in the forest carbon accounting methods (Bowen et al., 2011).
Materials and methods: In 2016 and 2017 over fifty five thousands increment cores were collected in the field by the French NFI. Wood density measurements were performed at INRA (Leban et al., 2019, this conference) and combined with the French NFI calculation system, biomass ratio can now be computed as a standard. This quantity can now be depicted over stratification variables such as soil water availability. An exploratory and ANOVA-assisted analysis of this gradient was performed.
Results: Biomass ratio was found strongly related to soil water availability, with a decrease of biomass ratio at the hardwood and softwood scale, but no correlation were found at the specie level. Explanations come from the species repartition along the gradients from high wood density to low density driven by soil water availability.
Conclusion: Wood density data acquired on the French NFI allow major steps forward toward the proper estimate of forest biomass resources and of carbon sequestration. Biomass ratio was found correlated with climatic contexts, suggesting that biomass sequestration at constant volume may increase in a warmer climate. But this change will be made through change of composition of the forest rather than an adaptation of the species.Numéro de notice : C2019-049 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Poster nature-HAL : Poster-avec-CL DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95768
Titre : Bridging the gap: toward a French MS-NFI for territories Type de document : Article/Communication Auteurs : Jean-Pierre Renaud Editeur : Paris [France] : Office national des forêts ONF Année de publication : 2019 Conférence : Conference 2019, A century of national forest inventories – informing past, present and future decisions 19/05/2019 21/05/2019 Oslo Norvège programme sans actes Langues : Anglais (eng) Descripteur : [Termes IGN] carte forestière
[Termes IGN] classification barycentrique
[Termes IGN] densité de la végétation
[Termes IGN] données auxiliaires
[Termes IGN] données de terrain
[Termes IGN] feuillu
[Termes IGN] forêt tempérée
[Termes IGN] image aérienne
[Termes IGN] image Landsat
[Termes IGN] modèle numérique de surface de la canopée
[Termes IGN] placette d'échantillonnage
[Termes IGN] surface terrière
[Termes IGN] volume en bois
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Introduction: National forest inventories are designed to produce statistics about forest attributes at a national to regional scales. Beyond these administrative units, the amount of points become limiting in terms of precision. In France, the establishment of regional programs for forest and wood (PRFB) require estimates at a smaller scale. The multisource inventory approaches allowed to bridge this gap (Tomppo et al. 2008). The methods rely on the combination of field plot information with auxiliary data (Kangas et al. 2018). The objective was to set up a multisource inventory workflow for the French Forest and to evaluate the gain in precision obtain at different administrative levels. Materials and methods: This research was conducted over a 7500 km2 area located in centre of France, of which 50 % is covered by forests dominated by broadleaved species. The forest area included 775 NFI plots collected during the 2009-2014 period. The auxiliary data were acquired in 2013-2014 and selected to fulfil the following criteria: Relevant, i.e. well correlated with the forest attributed under survey; Actualized Regularly for updating; Exhaustive over the whole territory; and Economical (RARE2). In this regard, we used the following data sources: Landsat images, 3D models derived from aerial photographs and a forest thematic map. We further evaluated the contribution of 3D models acquired 5 years apart in a subset area. The multisource approach relies on the non-parametric k-nearest neighbours (k-nn) approach owing to its multivariate capabilities. The k-nn was optimised for variable selection, number of neighbours (k) and distance metrics. Its performance was tested under a model-assisted framework using estimators from Mandallaz (2013) for various administrative levels. Results: Among the auxiliary variables tested, the 3D data source from aerial photographs performed best, as compared to Landsat, or forest thematic maps. The best combination of data included all sources and provide relative efficiencies (RE) varying from 2.05 for volume to 1.03 for stand density. Over the subset area, the diachronic data allow to improve the RE from 3-26 %. The diachronic data markedly improved the efficiency in estimations of forest type volumes, basal area and stand density. Similar RE were obtained for small area estimation at the scale of Canton and Municipalities. Conclusion: Our results confirmed the importance of 3D models of forest canopies and demonstrated the interest of canopy changes to improve precision of some forest attributes such as production volume and density, which are associated with fluxes. Numéro de notice : C2019-064 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96975
Titre : A large-scale forest dynamic model to estimate wood resources in the French forests based on NFI information Type de document : Article/Communication Auteurs : Timothée Audinot Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2019 Projets : MOPROF-CC / Conférence : Conference 2019, A century of national forest inventories – informing past, present and future decisions 19/05/2019 21/05/2019 Oslo Norvège programme sans actes Projets : ModForTrans / Bontemps, Jean-Daniel Langues : Anglais (eng) Descripteur : [Termes IGN] forêt
[Termes IGN] France métropolitaine
[Termes IGN] inventaire forestier national (données France)
[Termes IGN] modèle dynamique
[Termes IGN] ressources forestières
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Introduction : Non-stationary forest dynamics of secular arising from the forest transition, and current agenda on climate change mitigation and valuation of wood resources (Bioeconomy), make the development of large-scale models crucial to support forest management strategies on these issues. French forests further exhibit significant contrasts in climatic context and diversity in tree species, challenging these developments. Based on the MARGOT model (Pignard, 1993; Wernsdörfer et al., 2012), we intend to model all the diversity of the French forest in a non-stationary context.Materials and methods: Using NFI data to both build reference historical chronologies of growing stock and estimate model parameters, we compared past retrospective projections of model MARGOT, constructed at different hierarchical scales representative of diversity of the French forests, with historical and modern database from the French NFI over a period of 40 years (1971-2011), to conduct model evaluation. We also performed a sensitivity analysis on the felling rates. Second step is to represent density-dependent processes in the model in order to better simulate forest management. Results: MARGOT was found to overestimate the growing stock trajectories, both on a regional and national scale. A sensitivity analysis on felling rates suggested their underestimation from the NFI protocol by a factor of 2, as a consequence of the temporary nature of sampling plots. Modelling of density-dependence was introduced and tested against former simulations.Conclusion: In spite of overestimations in the growing stock, MARGOT was found able to describe the French forest expansion, indicating that forest maturation is a key current process in these increases. Density-dependence was found to lower overestimations in the growing stock. A next step will consist in hybridizing Margot with a process-based model in order to account for climatic forcings. Numéro de notice : C2019-063 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96976
Titre : The French NFI : flexibility at the heart of the design Type de document : Article/Communication Auteurs : François Morneau Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2019 Conférence : Conference 2019, A century of national forest inventories – informing past, present and future decisions 19/05/2019 21/05/2019 Oslo Norvège programme sans actes Langues : Anglais (eng) Descripteur : [Termes IGN] échantillonnage
[Termes IGN] estimateur
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] inventaire forestier national (données France)
[Termes IGN] modèle numérique de surface de la canopée
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Introduction : The growing demands of society on forests have pushed forward NFIs who had to evolve and adapt over time. However, in a context of forests being at the center of many challenges, reactivated by global changes, this adaptation has been particularly accelerated in recent years. The demands now comes from a broader public (national/international policy makers, industries, environmental organisations, research, people) who is seeking for more information, more precise and easily accessible. In order to respond to these demands, some NFIs are moving from a knowledge tool on forests to a somehow environmental monitoring system. These renewed inventories must be able to easily integrate new (diverse) needs and to be reactive in case of dramatic perturbations (fires, storms, massive dieback). In this context, NFIs must be powerful, responsive and easily adaptable tools. This involves a change in their design, from the sampling plan, to the provision of baseline information through revised estimation techniques using more and more auxiliary information, often derived from remote sensing. The purpose of the communication is to present the innovations implemented or under development in the French inventory to adapt a quite old (now 60 years) tool to this new context.
Materials and methods: The communication will present the recent changes in the French NFI :•sampling design (continuous inventory);•estimators and the use of external data thanks to post-stratification.
Results: We will insist on the search for flexibility of the French NFI design and the information system actually developed :•On the fly production of results via specific tools;•Easy addition, combination of new variables;•Improvement of estimates thanks to new data via post-stratification (DHM);•Derivation of the national tool to specific case (regional) studies : on demand inventories.•Reactivity after events like storms. Conclusion: A NFI is a work in progress, always evolving to address new needs, gain more precision, a finest resolution... at constant or decreasing costs. New solutions have to be found, new auxiliary data have to be mobilised in order to answer the multiple demands. Achieving that necessitate to find or form the future engineers and researchers who will build the next generation of NFIs. This question is crucial in a domain where human resources are rare.Numéro de notice : C2019-062 Affiliation des auteurs : LIF (2012-2019) Thématique : FORET Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96977 
Titre : Toward the development of total volume and biomass functions using terrestrial lidar and NFI data Type de document : Article/Communication Auteurs : Cédric Vega Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2019 Conférence : Conference 2019, A century of national forest inventories – informing past, present and future decisions 19/05/2019 21/05/2019 Oslo Norvège programme sans actes Langues : Anglais (eng) Descripteur : [Termes IGN] biomasse forestière
[Termes IGN] données lidar
[Termes IGN] inventaire forestier national (données France)
[Termes IGN] volume en bois
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Introduction : The diversification of wood usages and the information needs for international reporting require detailed information on total tree volume and biomass. National Forest Inventories have traditionally estimated merchantable volume based on diameter and height measures and allometric models, but they need to get new efficient ways to estimate of total tree volume and biomass (Vallet et al. 2006). In France, current approaches suffer from databases restricted to a limited number of species or tree size range (Henry et al. 2010), and their long term validity could be limited by the impact of climate change on tree growth (Charru et al. 2017). Terrestrial Laser Scanning (TLS) is seen as a promising tool to model tree geometry and estimate total tree volume and biomass without- or limited - destructive measurements. Various approaches have been proposed in the litterature to extract tree attributes, from single measurements (i.e. dbh) to full tree reconstruction (Liang et al. 2018). The latter were initially developed for tree-level processing and relied on of very high density points clouds. Such point clouds were found suitable to estimate total tree volume and biomass. The challenge for NFIs is to acquire and process TLS data acquired over a large number of forest plots at a marginal cost. The purpose of this presentation is to provide experience feedback on the development of such a paradigm in the French NFI.
Materials and methods: The TLS processing chain included both data acquisition protocols and point cloud processing methods. The acquisition part started in 2010 with 4 scan positions per plot, without any additional field measurements. After scanning ~ 1,500 plots, this setup was revised in 2016 to improve the point cloud quality and validation data. The current setup includes 9 scans per plot in a 10 m circle. The traditional volume table protocol is currently applied to obtain additional measurements along the main stem. The point cloud processing chain was implemented under Computree processing platform in the framework of the H2020-project DIABOLO, to extract individual tree geometry and volume. It is based on the SimpleTree approach (Hackenberg et al. 2015), and includes the following main steps: terrain modelling, tree localisation and segmentation, tree reconstruction and consolidation, and volume computation. It was tested on both NFI (25 plots) data and detailed databases based on destructive sample from various sources (Lin2Value, Emerge projects, 76 trees).
Results: The developed method allowed to estimate total tree volume with a mean error of -0.1 m3(±0.4 SD) and a RMSE of 23.47%. In terms of NFI measurements, the DBH and Diameter at 2.6 m were estimated with a precision of 0.24 cm (±0.4 SD) or 0.27 cm (± 1.95 SD) and RMSE of respectively 5.82 % and 8.93 %. As regards cut height and total tree heights, errors were 0.78 m (± 2.5 SD) and 1.48 m (± 1.93 SD). The corresponding RMSE were 27.91 % and 13.84 % respectively(Hackenberg et al. 2017).
Conclusion: The current TLS data acquisition and processing chain provides promising results towardthe development of total volume and biomass functions for NFIs. Future work will focus on improving the field validation protocols and the reconstruction method of the upper canopy, where the point density is limited due to distance and occlusions.Numéro de notice : C2019-061 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Communication nature-HAL : ComSansActesPubliés-Unpublished DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96978 Documents numériques
peut être téléchargé
c2019-071-towards an improved forest inventory _JarbouiAdobe Acrobat PDF
