Descripteur
Documents disponibles dans cette catégorie (86)
Ajouter le résultat dans votre panier
Visionner les documents numériques
Affiner la recherche Interroger des sources externes
Etendre la recherche sur niveau(x) vers le bas
Multi-species individual tree segmentation and identification based on improved mask R-CNN and UAV imagery in mixed forests / Chong Zhang in Remote sensing, vol 14 n° 4 (February-2 2022)
[article]
Titre : Multi-species individual tree segmentation and identification based on improved mask R-CNN and UAV imagery in mixed forests Type de document : Article/Communication Auteurs : Chong Zhang, Auteur ; Jiawei Zhou, Auteur ; Huiwen Wang, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 874 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] Chine
[Termes IGN] classification par réseau neuronal convolutif
[Termes IGN] détection de contours
[Termes IGN] échantillonnage de données
[Termes IGN] entropie
[Termes IGN] estimation quantitative
[Termes IGN] feuillu
[Termes IGN] hauteur des arbres
[Termes IGN] image captée par drone
[Termes IGN] peuplement mélangé
[Termes IGN] Pinophyta
[Termes IGN] segmentation d'imageRésumé : (auteur) High-resolution UAV imagery paired with a convolutional neural network approach offers significant advantages in accurately measuring forestry ecosystems. Despite numerous studies existing for individual tree crown delineation, species classification, and quantity detection, the comprehensive situation in performing the above tasks simultaneously has rarely been explored, especially in mixed forests. In this study, we propose a new method for individual tree segmentation and identification based on the improved Mask R-CNN. For the optimized network, the fusion type in the feature pyramid network is modified from down-top to top-down to shorten the feature acquisition path among the different levels. Meanwhile, a boundary-weighted loss module is introduced to the cross-entropy loss function Lmask to refine the target loss. All geometric parameters (contour, the center of gravity and area) associated with canopies ultimately are extracted from the mask by a boundary segmentation algorithm. The results showed that F1-score and mAP for coniferous species were higher than 90%, and that of broadleaf species were located between 75%–85.44%. The producer’s accuracy of coniferous forests was distributed between 0.8–0.95 and that of broadleaf ranged in 0.87–0.93; user’s accuracy of coniferous was distributed between 0.81–0.84 and that of broadleaf ranged in 0.71–0.76. The total number of trees predicted was 50,041 for the entire study area, with an overall error of 5.11%. The method under study is compared with other networks including U-net and YOLOv3. Results in this study show that the improved Mask R-CNN has more advantages in broadleaf canopy segmentation and number detection. Numéro de notice : A2022-168 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.3390/rs14040874 Date de publication en ligne : 11/02/2022 En ligne : https://doi.org/10.3390/rs14040874 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99793
in Remote sensing > vol 14 n° 4 (February-2 2022) . - n° 874[article]Landsat-based monitoring of southern pine beetle infestation severity and severity change in a temperate mixed forest / Ran Meng in Remote sensing of environment, vol 269 (February 2022)
[article]
Titre : Landsat-based monitoring of southern pine beetle infestation severity and severity change in a temperate mixed forest Type de document : Article/Communication Auteurs : Ran Meng, Auteur ; Renjie Gao, Auteur ; Feng Zhao, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 112847 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection
[Termes IGN] analyse spatiale
[Termes IGN] dépérissement
[Termes IGN] forêt tempérée
[Termes IGN] image Landsat-8
[Termes IGN] insecte nuisible
[Termes IGN] mortalité
[Termes IGN] peuplement mélangé
[Termes IGN] Scolytinae
[Termes IGN] signature spectrale
[Termes IGN] surveillance forestière
[Termes IGN] xylophageRésumé : (auteur) The recent northward expansion of Southern Pine Beetle (SPB) outbreaks associated with warming winters has caused extensive tree mortality in temperate pine forests, significantly affecting forest dynamics, structure, and functioning. Spatially-explicit early warning and detection of SPB-induced tree mortality is critical for timely and sustainable forest management practices. The unique contributions of remote sensing technologies to mapping the location, extent, and severity of beetle outbreaks, as well as assisting in analyzing the potential drivers for outbreak predictions, have been well recognized. However, little is known about the performance of moderate resolution satellite multispectral imagery for early warning and detection of SPB-induced tree mortality. Thus, we conducted this study, as the first attempt, to capture the spatial-temporal patterns of SPB infestation severity at the regional scale and to understand the underlying environmental drivers in a spatially-explicit manner. First, we explored the spectral signatures of SPB-killed trees based on 30-m plot measurements and Landsat-8 imagery. Then, to improve detection accuracy for areas with low-moderate SPB infestation severity, we added spectral-temporal anomaly information in the form of a linear trend of the spectral index trajectory to a previously developed approach. The best overall accuracy increased from 84.7% to 90.1% and the best Macro F1 value increased from 0.832 to 0.900. Next, we compared the performances of spectral indices in mapping SPB infestation severity (i.e., % red stage within the 30-m grid cell). The results showed that the combination of Normalized Difference Moisture Index and Tasseled Cap Greenness had the best performance for mapping SPB infestation severity (2016: R2 = 0.754; RSME = 15.7; 2017: R2 = 0.787; RSME = 12.4). Finally, we found that climatic and landscape variables can explain the detected patterns of SPB infestation from 2014 to 2017 in our study area (R2 = 0.751; RSME = 9.67), providing valuable insights on possible predictors for early warning of SPB infestation. Specifically, in our study area, winter dew point temperature was found to be one of the most important predictors, followed by SPB infestation locations in the previous year, canopy cover of host species, elevation, and slope. In the context of continued global warming, our study not only provides a novel framework for efficient, spatially-explicit, and quantitative measurements of forest damage induced by SPB infestation over large scales, but also uncovers opportunities to predict future SPB outbreaks and take precautions against it. Numéro de notice : A2022-096 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1016/j.rse.2021.112847 Date de publication en ligne : 15/12/2021 En ligne : https://doi.org/10.1016/j.rse.2021.112847 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99538
in Remote sensing of environment > vol 269 (February 2022) . - n° 112847[article]Forest floor alteration by canopy trees and soil wetness drive regeneration of a spruce-beech forest / Pavel Daněk in Forest ecology and management, vol 504 (January-15 2022)
[article]
Titre : Forest floor alteration by canopy trees and soil wetness drive regeneration of a spruce-beech forest Type de document : Article/Communication Auteurs : Pavel Daněk, Auteur ; Pavel Šamonil, Auteur ; Libor Hort, Auteur Année de publication : 2022 Article en page(s) : n° 119802 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] bois mort
[Termes IGN] canopée
[Termes IGN] Fagus sylvatica
[Termes IGN] humidité du sol
[Termes IGN] litière
[Termes IGN] peuplement mélangé
[Termes IGN] Picea abies
[Termes IGN] régénération (sylviculture)
[Termes IGN] République Tchèque
[Termes IGN] semis (sylviculture)
[Termes IGN] sol forestier
[Vedettes matières IGN] ForesterieRésumé : (auteur) Natural regeneration of European beech (Fagus sylvatica) and Norway spruce (Picea abies) plays a crucial role in the future of many European mountain forests. It is affected by various soil and stand-related factors whose relative importance, especially in mixed stands, is still not known. In this study, we assessed the importance of stand composition, soil wetness, disturbances and different microsites and seedbeds for regeneration of beech and spruce in a mixed old-growth mountain forest. We also focused on how the effects of these factors change as regeneration gets older. We sampled all regeneration in 563 plots from different microsite types (deadwood, intact soil, treethrow pits and mounds), distinguishing three seedbeds (mosses, beech litter, bare substrate) for seedlings. We used soil survey and tree census data with generalized linear mixed models and variance partitioning to identify the main factors driving tree regeneration and their relative importance. Although beech was slightly less abundant in the canopy than spruce, it strongly outnumbered spruce in regeneration. Beech regeneration showed an affinity for beech litter-rich microsites and drier soils, while spruce was more common on deadwood and moister soils and its response to the seedbed was microsite-specific. The regeneration of both species was positively related to the proportion of their own species in the canopy, but more so in seedlings than in older regeneration cohorts, where soil wetness was more important. The overall pattern of tree regeneration thus resulted from a complex interplay between site conditions and their alterations by current and former generations of canopy trees through the creation of new microsites (deadwood, uprooting mounds) or litter production. Where beech regeneration is not suppressed by excess soil wetness, it is much more successful than spruce due to its shade tolerance and ability to be established in the beech litter that dominates the forest floor. On the other hand, spruce regeneration is mostly restricted to elevated microsites with lower litter accumulation, such as deadwood and treethrow mounds. Our results indicate that both species exhibit an ability to modify their environment in favor of their own regeneration, but under current conditions, beech is more successful than spruce and can be expected to increase its dominance in the future. Numéro de notice : A2022-022 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1016/j.foreco.2021.119802 Date de publication en ligne : 04/11/2021 En ligne : https://doi.org/10.1016/j.foreco.2021.119802 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99214
in Forest ecology and management > vol 504 (January-15 2022) . - n° 119802[article]New insights in the modeling and simulation of tree and stand level variables in Mediterranean mixed forests in the present context of climate change / Diego Rodríguez de Prado (2022)
Titre : New insights in the modeling and simulation of tree and stand level variables in Mediterranean mixed forests in the present context of climate change Type de document : Thèse/HDR Auteurs : Diego Rodríguez de Prado, Auteur ; Celia Herrero de Aza, Directeur de thèse ; Felipe Bravo Oviedo, Directeur de thèse Editeur : Valladolid [Espagne] : Université de Valladolid Année de publication : 2022 Importance : 168 p. Format : 21 x 30 cm Note générale : bibliographie
Doctoral dissertation, Valladolid UniversityLangues : Anglais (eng) Descripteur : [Termes IGN] allométrie
[Termes IGN] climat aride
[Termes IGN] croissance des arbres
[Termes IGN] Espagne
[Termes IGN] Fagus sylvatica
[Termes IGN] forêt méditerranéenne
[Termes IGN] gestion forestière adaptative
[Termes IGN] hauteur des arbres
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] modélisation de la forêt
[Termes IGN] peuplement mélangé
[Termes IGN] Pinus nigra
[Termes IGN] Pinus pinaster
[Termes IGN] Pinus sylvestris
[Termes IGN] puits de carbone
[Termes IGN] Quercus pyrenaica
[Vedettes matières IGN] Végétation et changement climatiqueIndex. décimale : THESE Thèses et HDR Résumé : (auteur) An increase of droughts intensity and frequency episodes combined with new extreme climate events are predicted to appear in the Mediterranean Basin due to global warming. In this context, mixed forests have become a sustainable opportunity to mitigate the effects of climate change. Species mixing may lead to the provision of a greater variety of ecosystem services and products while increasing temporal stability compared to pure forests. The development of new models that explain different tree and stand level variables may be vital to better understand the structure, composition and dynamics of this type of forests. In addition, it is essential to analyze how climate may influence these variables in order to design adaptive and sustainable management guidelines for mixed forests under future climate change scenarios. In this study, we sought to advance in the modelization and simulation of different tree and stand level variables along a range of different forest and aridity conditions in Spain. To achieve that, climate-dependent models were fitted using data from the Spanish National Forest Inventory and the WorldClim databases. We focused our study on fifteen Mediterranean tree species from the Pinus, Quercus, and Fagus genus. In our first study, we analyzed how climate may potentially influence the maximum stand carrying capacity, by terms of the maximum stand carrying capacity (SDImax), for the species under study in pure stands. This variable was chosen because its importance in (1) managing density and (2) defining species mixing proportions in mixed forest stands. To do that, climate-dependent MSDR models were fitted for each species under study. 35 different climatic annual and seasonal variables (temperature, precipitation, evapotranspiration, aridity indexes) were simultaneously included into the models. In this study, climate was found to have significant influence on MSDR, and therefore on the maximum stand carrying capacity (SDImax). The best climate-dependent MSDR models indicated that climatic variables related to temperature better explained the influence of climate on MSDR. Specifically, seasonal (MXTi) and annual (MXT) maximum temperatures were the most representative climatic variables explaining changes in MSDR. Based on the selected seasonal variables, spring and summer were consistently appeared as key periods. A common trend in SDImax variation for coniferous and broadleaf species was found, with higher SDImax values negatively linked to temperature and positively linked to precipitation. This trend suggested that aridity may play a key role reducing the maximum stand 12 carrying capacity of the main Mediterranean tree species. In addition, the impact of climate on maximum stand carrying capacity was evaluated by the creation of the Q index. In general, broadleaved species presented higher values of Q indexes than coniferous species, suggesting that the maximum stand carrying capacity of the first ones would suffer more the influence of potential climate changes. Our findings highlight the importance of using specific climatic variables to better characterize how they affect MSDR. Since we saw that aridity could play a key role influencing stand level variables such as SDImax, we aimed to analyze how it may influence tree growth and tree allometry. Moreover, we aimed to analyze how species mixing effects may influence these variables on mixed forests. Thus, two more studies focused on 29 two-species Mediterranean mixtures were developed. To study the influence of aridity and species mixing on tree growth, the basal area increment within a span of five years (BAI5), was modelled based on individual tree size, stand development and other variables of site and competition. Two distance independent competition indexes were considered: total stand basal area (BA) representing size-symmetric competition, and the basal area of trees larger than the subject tree (BAL) representing size-asymmetric competition. To uncover the complex mixing effects on basal area increment at tree level, competition indexes were splitting into intraspecific and interspecific components. All possible combinations of competition structures were included and tested in the BAI models. Positive, negative or neutral mixing effects were determined by comparing the intraspecific and interspecific component of the selected models. Then, the biological interactions taking place between species were determined based on size-symmetric and sizeasymmetric competition. Finally, the influence of aridity on basal area increment was studied including the De Martonne Index into the BAI models. A common trend among mixtures was found with higher productivity in mixed than pure stands, suggesting that BAI values may increase with the increment of species diversity. Based on model parameters, a novel approach to determine potential biological interactions between species in mixed forests was also presented in this study. Competition seemed to be the most representative biological interaction in coniferconifer mixtures, since neutralism and facilitation may occur more frequently in conifer-broadleaved and broadleaved-broadleaved mixtures. Our findings also suggested that tree productivity may be significantly limited by arid conditions, excepting for Pinus halepensis and Pinus pinea [...] Note de contenu : 1- Introduction
2- Objectives
3- Data
4- Methods
5- Results
6- Discussion
ConclusionNuméro de notice : 24064 Affiliation des auteurs : non IGN Thématique : FORET Nature : Thèse étrangère Note de thèse : Thèse de Doctorat : Systemes Forestiers Durables : Valladolid : 2022 Organisme de stage : Sustainable Forest Management Research Institute (Université de Valladolid) DOI : sans En ligne : https://uvadoc.uva.es/handle/10324/55195 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102046 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)
[article]
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] ForesterieRésumé : (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
in Annals of Forest Science > vol 78 n° 4 (December 2021) . - n° 92[article]Early detection of pine wilt disease using deep learning algorithms and UAV-based multispectral imagery / Run Yu in Forest ecology and management, vol 497 (October-1 2021)PermalinkDetection of aspen in conifer-dominated boreal forests with seasonal multispectral drone image point clouds / Alwin A. Hardenbol in Silva fennica, vol 55 n° 4 (September 2021)PermalinkCalibration of the process-based model 3-PG for major central European tree species / David I. Forrester in European Journal of Forest Research, vol 140 n° 4 (August 2021)PermalinkThe presence of shade-intolerant conifers facilitates the regeneration of Quercus petraea in mixed stands / Jeremy Borderieux in Forest ecology and management, vol 491 (July-1 2021)PermalinkUnmanned aerial vehicles (UAV)-based canopy height modeling under leaf-on and leaf-off conditions for determining tree height and crown diameter (Case study: Hyrcanian mixed forest) / Vahid Nasiri in Canadian Journal of Forest Research, Vol 51 n° 7 (July 2021)PermalinkCharacterization of mixed and monospecific stands of Scots pine and Maritime pine: soil profile, physiography, climate and vegetation cover data / Daphne Lopez-Marcos in Annals of Forest Science, vol 78 n° 2 (June 2021)PermalinkIndividual tree identification using a new cluster-based approach with discrete-return airborne LiDAR data / Haijian Liu in Remote sensing of environment, vol 258 (June 2021)PermalinkMixture effect on radial stem and shoot growth differs and varies with temperature / Maude Toïgo in Forest ecology and management, vol 488 (May-15 2021)PermalinkSelf-thinning tree mortality models that account for vertical stand structure, species mixing and climate / David I. Forrester in Forest ecology and management, Vol 487 ([01/05/2021])PermalinkAre pine-oak mixed stands in Mediterranean mountains more resilient to drought than their monospecific counterparts? / Francisco J. Muñoz-Gálvez in Forest ecology and management, vol 484 ([15/03/2021])Permalink