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Modeling diameter distributions in radiata pine plantations in Spain with existing countrywide LiDAR data / Manuel Arias-Rodil in Annals of Forest Science, vol 75 n° 2 (June 2018)  

Public [article]  inAnnals of Forest Science > vol 75 n° 2 (June 2018) Titre : Modeling diameter distributions in radiata pine plantations in Spain with existing countrywide LiDAR data Type de document : Article/Communication Auteurs : Manuel Arias-Rodil, Auteur ; Ulises Diéguez-Aranda, Auteur ; Juan Gabriel Álvarez-González, Auteur ; César Pérez-Cruzado, Auteur ; et al., Auteur Année de publication : 2018 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] classification par forêts d'arbres décisionnels [Termes IGN] diamètre des arbres [Termes IGN] distance de Kolmogorov-Smirnov [Termes IGN] données altimétriques [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] Espagne [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] Pinus radiata [Vedettes matières IGN] Inventaire forestier Résumé : (Auteur) Key message: We evaluated the use of low-density airborne laser scanning data to estimate diameter distributions in radiata pine plantations. The moment-based parameter recovery method was used to estimate the diameter distributions, considering LiDAR metrics as explanatory variables. The fitted models explained more than 77% of the observed variability. This approach can be replicated every 6 years (temporal cover planned for countrywide LiDAR flights in Spain). Context:The estimation of stand diameter distribution is informative for forest managers in terms of stand structure, forest growth model inputs, and economic timber value. In this sense, airborne LiDAR may represent an adequate source of information. Aims: The objective was to evaluate the use of low-density Spanish countrywide LiDAR data for estimating diameter distributions in Pinus radiata D. Don stands in NW Spain. Methods: The empirical distributions were obtained from 25 sample plots. We applied the moment-based parameter recovery method in combination with the Weibull function to estimate the diameter distributions, considering LiDAR metrics as explanatory variables. We evaluated the results by using the Kolmogorov–Smirnov (KS) test and a classification tree and random forest (RF) to relate the KS test result for each plot to stand-level variables. Results: The models used to estimate average (dm) and quadratic (dg) mean diameters from LiDAR metrics, required for recovery of the Weibull parameters, explained a high percentage of the observed variance (77 and 80%, respectively), with RMSE values of 3.626 and 3.422 cm for the same variables. However, the proportion of plots accepted by the KS was low. This poor performance may be due to the strictness of the KS test and/or by the characteristics of the LiDAR flight. Conclusion: The results justify the assessment of this approach over different species and forest types in regional or countrywide surveys. Numéro de notice : A2018-327 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-018-0712-z Date de publication en ligne : 16/03/2018 En ligne : https://doi.org/10.1007/s13595-018-0712-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90470 [article]

Developing a dynamic growth model for maritime pine in Asturias (NW Spain): comparison with nearby regions / Manuel Arias-Rodil in Annals of Forest Science, vol 73 n° 2 (June 2016)  

Public [article]  inAnnals of Forest Science > vol 73 n° 2 (June 2016) . - pp 297 - 320 Titre : Developing a dynamic growth model for maritime pine in Asturias (NW Spain): comparison with nearby regions Type de document : Article/Communication Auteurs : Manuel Arias-Rodil, Auteur ; Marcos Barrio-Anta, Auteur ; Ulises Diéguez-Aranda, Auteur Année de publication : 2016 Article en page(s) : pp 297 - 320 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes IGN] bois sur pied [Termes IGN] croissance des arbres [Termes IGN] Espagne [Termes IGN] hauteur des arbres [Termes IGN] modèle de simulation [Termes IGN] Pinus pinaster [Termes IGN] statistique descriptive [Termes IGN] surface terrière Résumé : (auteur) Key message: A dynamic growth model was developed for maritime pine in Asturias. During the evaluation process, a stand volume ratio function proved the best of two alternative methods for estimating merchantable volume. Comparison of the developed model with existing models for nearby regions showed that a single model may suffice for the whole of the NW Iberian Peninsula. Context: Maritime pine is one of the most important tree species in NW Spain. There was no existing dynamic growth model for this species in Asturias. Aims: To develop a dynamic growth model for maritime pine in Asturias, by evaluating two different methods of estimating volume (a disaggregation system and a stand volume ratio function), and to compare the developed model with existing models for Galicia and northern Portugal are the goals of this study. Methods: The dynamic model is based on the state-space approach, in which three state variables characterize the stand at any point in time: dominant height, number of stems per hectare and stand basal area. The transition function for the first variable was developed on the basis of stem analysis data in a previous study, while the corresponding functions for the last two variables were simultaneously fitted with data obtained from successive measurements of permanent plots. An appendix outlining the implementation of a stand growth simulator in the R environment is included to facilitate model use and evaluation. Results: When the whole model was used to project the stand conditions, the stand volume ratio function performed best, yielding a root mean square error of 22.4 m3 ha−1 and a critical error of 18.4 %. Comparison with models developed for other regions revealed both similarities and differences, some of which may be attributed to an unequal distribution of the available data in age and site quality classes. Conclusion: The proposed dynamic growth model provided accurate results, and comparison with other region-specific models showed that a single dynamic model may suffice for the whole of the NW Iberian Peninsula. Numéro de notice : A2016-350 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-015-0501-x Date de publication en ligne : 25/08/2015 En ligne : https://doi.org/10.1007/s13595-015-0501-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81059 [article]