Centre dedocumentation
scientifique

Radiative transfer modeling in structurally complex stands: towards a better understanding of parametrization / Frédéric André in Annals of Forest Science, vol 78 n° 4 (December 2021)  

Public [article]  inAnnals of Forest Science > vol 78 n° 4 (December 2021) . - n° 92 Titre : Radiative transfer modeling in structurally complex stands: towards a better understanding of parametrization Type de document : Article/Communication Auteurs : Frédéric André, Auteur ; Louis de Wergifosse, Auteur ; François de Coligny, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 92 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Belgique [Termes IGN] couvert forestier [Termes IGN] croissance des arbres [Termes IGN] densité du feuillage [Termes IGN] diamètre à hauteur de poitrine [Termes IGN] estimation bayesienne [Termes IGN] Fagus sylvatica [Termes IGN] houppier [Termes IGN] Leaf Mass per Area [Termes IGN] modèle de croissance végétale [Termes IGN] modèle de transfert radiatif [Termes IGN] peuplement mélangé [Termes IGN] photosynthèse [Termes IGN] production primaire brute [Termes IGN] production primaire nette [Termes IGN] Quercus sessiliflora [Termes IGN] structure d'un peuplement forestier [Vedettes matières IGN] Foresterie Résumé : (auteur) Key message: The best options to parametrize a radiative transfer model change according to the response variable used for fitting. To predict transmitted radiation, the turbid medium approach performs much better than the porous envelop, especially when accounting for the intra-specific variations in leaf area density but crown shape has limited effects. When fitting with tree growth data, the porous envelop approach combined with the more complex crown shape provides better results. When using a joint optimization with both variables, the better options are the turbid medium and the more detailed approach for describing crown shape and leaf area density. Context: Solar radiation transfer is a key process of tree growth dynamics in forest. Aims: Determining the best options to parametrize a forest radiative transfer model in heterogeneous oak and beech stands from Belgium. Methods: Calibration and evaluation of a forest radiative transfer module coupled to a spatially explicit tree growth model were repeated for different configuration options (i.e., turbid medium vs porous envelope to calculate light interception by trees, crown shapes of contrasting complexity to account for their asymmetry) and response variables used for fitting (transmitted radiation and/or tree growth data). Results: The turbid medium outperformed the porous envelope approach. The more complex crown shapes enabling to account for crown asymmetry improved performances when including growth data in the calibration. Conclusion: Our results provide insights on the options to select when parametrizing a forest radiative 3D-crown transfer model depending on the research or application objectives. Numéro de notice : A2021-768 Affiliation des auteurs : non IGN Thématique : FORET/MATHEMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-021-01106-8 Date de publication en ligne : 26/10/2021 En ligne : https://doi.org/10.1007/s13595-021-01106-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99010 [article]

CO2 fertilization, transpiration deficit and vegetation period drive the response of mixed broadleaved forests to a changing climate in Wallonia / Louis de Wergifosse in Annals of Forest Science, vol 77 n° 3 (September 2020)  

Public [article]  inAnnals of Forest Science > vol 77 n° 3 (September 2020) . - 23 p. Titre : CO2 fertilization, transpiration deficit and vegetation period drive the response of mixed broadleaved forests to a changing climate in Wallonia Type de document : Article/Communication Auteurs : Louis de Wergifosse, Auteur ; Frédéric André, Auteur ; Hugues Goosse, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : 23 p. Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] dioxyde de carbone [Termes IGN] écosystème forestier [Termes IGN] émission de gaz [Termes IGN] évapotranspiration [Termes IGN] forêt de feuillus [Termes IGN] gaz à effet de serre [Termes IGN] modèle de croissance végétale [Termes IGN] modèle de simulation [Termes IGN] production primaire brute [Termes IGN] stress hydrique [Termes IGN] Wallonie (Belgique) [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) Key message: The change in forest productivity was simulated in six stands in Wallonia (Belgium) following different climate scenarios using a process-based and spatially explicit tree growth model. Simulations revealed a strong and positive impact of the CO 2 fertilization while the negative effect of the transpiration deficit was compensated by longer vegetation periods. The site modulated significantly the forest productivity, mainly through the stand and soil characteristics. Context: Forest net primary production (NPP) reflects forest vitality and is likely to be affected by climate change. Aims: Simulating the impact of changing environmental conditions on NPP and two of its main drivers (transpiration deficit and vegetation period) in six Belgian stands and decomposing the site effect. Methods: Based on the tree growth model HETEROFOR, simulations were performed for each stand between 2011 and 2100 using three climate scenarios and two CO2 modalities (constant vs time dependent). Then, the climate conditions, soils and stands were interchanged to decompose the site effect in these three components. Results: In a changing climate with constant atmospheric CO2, NPP values remained constant due to a compensation of the negative effect of increased transpiration deficit by a positive impact of longer vegetation periods. With time-dependent atmospheric CO2, NPP substantially increased, especially for the scenarios with higher greenhouse gas (GHG) emissions. For both atmospheric CO2 modalities, the site characteristics modulated the temporal trends and accounted in total for 56 to 73% of the variability. Conclusion: Long-term changes in NPP were primarily driven by CO2 fertilization, reinforced transpiration deficit, longer vegetation periods and the site characteristics. Numéro de notice : A2020-594 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-020-00966-w Date de publication en ligne : 14/07/2020 En ligne : https://doi.org/10.1007/s13595-020-00966-w Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95932 [article]