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Model-dependent forest stand-level inference with and without estimates of stand-effects / Magnussen, Steen in Forestry, an international journal of forest research, vol 90 n° 5 (December 2017)
[article]
Titre : Model-dependent forest stand-level inference with and without estimates of stand-effects Type de document : Article/Communication Auteurs : Magnussen, Steen, Auteur ; Johannes Breidenbach, Auteur Année de publication : 2017 Article en page(s) : pp 675 - 685 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] incertitude des données
[Termes IGN] inférence statistique
[Termes IGN] inventaire forestier (techniques et méthodes)
[Vedettes matières IGN] Inventaire forestierRésumé : (Auteur) Forest stands are important units of management. A stand-by-stand estimation of the mean and variance of an attribute of interest (Y) remains a priority in forest enterprise inventories. The advent of powerful and cost effective remotely sensed auxiliary variables (X) correlated with Y means that a census of X in the forest enterprise is increasingly available. In combination with a probability sample of Y, the census affords a model-dependent stand-level inference. It is important, however, that the sampling design affords an estimation of possible stand-effects in the model linking X to Y. We demonstrate, with simulated data, that failing to quantify non-zero stand-effects in the intercept of a linear population-level model can lead to a serious underestimation of the uncertainty in a model-dependent estimate of a stand mean, and by extension a confidence interval with poor coverage. We also provide an approximation to the variance of stand-effects in an intercept for the case when a sampling design does not afford estimation. Furthermore, we propose a method to correct a potential negative bias in an estimate of the variance of stand-effects when a sampling design prescribes few stands with small within-stand sample sizes. Numéro de notice : A2017-903 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1093/forestry/cpx023 En ligne : https://doi.org/10.1093/forestry/cpx023 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93197
in Forestry, an international journal of forest research > vol 90 n° 5 (December 2017) . - pp 675 - 685[article]Microtopography and ecology of pit-mound structures in second-growth versus old-growth forests / Audrey Barker Plotkin in Forest ecology and management, vol 404 (15 November 2017)
[article]
Titre : Microtopography and ecology of pit-mound structures in second-growth versus old-growth forests Type de document : Article/Communication Auteurs : Audrey Barker Plotkin, Auteur ; Peter Schoonmaker, Auteur ; Bennet Leon, Auteur ; David Foster, Auteur Année de publication : 2017 Article en page(s) : pp 14 - 23 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation
[Termes IGN] analyse comparative
[Termes IGN] Betula (genre)
[Termes IGN] forêt ancienne
[Termes IGN] microtopographie
[Termes IGN] richesse floristique
[Termes IGN] structure d'un peuplement forestier
[Termes IGN] tempêteRésumé : (auteur) Pit and mound microtopography is an important structural component of most forests, influencing soil processes and habitat diversity. These features have diminished greatly in northeastern U.S. forests since European settlement, as a result of the history of repeated logging, land-clearance followed by reforestation, and the smaller size of trees (and therefore windthrow features) comprising the prevailing second-growth forests. Despite the potential importance of this region-wide shift in forest microtopography on ecosystem structure and function, the differences in pit and mound size, distribution, and longevity between second-growth and old-growth forests are unexplored. Likewise, although many studies demonstrate that mounds and/or pits are hotspots for tree regeneration there is scant information about whether location on a mound or pit affects tree survival and growth beyond the seedling stage, or whether microtopographic regeneration patterns differ in old-growth and second-growth forests.
We compare a simulated hurricane experiment initiated in 1990 in second-growth forest (the pulldown) and an old-growth forest that was blown down by a hurricane in 1938 (Pisgah) to examine differences in pit-mound microtopography and ecology between second-growth and old-growth forest. At Pisgah, fewer, larger mounds comprised a similar areal coverage as at the pulldown. Repeated measurements of individual pit-mound structures in the pulldown revealed that pit infill proceeded more rapidly than mound erosion. Mound area increased but height decreased over time as soil from the mound tops eroded and spread around the mound base. Although 40% of mounds in the pulldown were >1 m tall immediately after the manipulation (maximum of 2.9 m), after 25 years, maximum mound height was 0.9 m. In contrast, 11% of mounds at Pisgah remained >1 m tall in 1989, 50 years after blowdown. At both sites, trees, especially Betula spp., were disproportionately found on mounds. Fewer trees than expected grew in pits at Pisgah. Tree mortality was somewhat higher on mounds and pits than on other substrates. As a mechanism to increase stand-level tree diversity, windthrow may be more critical in old-growth forests, in which niches for early-mid successional species are few, than in second-growth forest, in which early-mid successional species already comprise the majority of the trees. Pit-mound structures are a diminished component of second-growth forest, and silvicultural techniques designed to restore old-growth characteristics could include measures to preserve and enhance pit-mound features, and to cultivate large-diameter trees that will eventually create the large, long-lasting pit-mounds of the future.Numéro de notice : A2017-806 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1016/j.foreco.2017.08.012 En ligne : https://doi.org/10.1016/j.foreco.2017.08.012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89243
in Forest ecology and management > vol 404 (15 November 2017) . - pp 14 - 23[article]An examination of diameter density prediction with k-NN and airborne lidar / Jacob L. Strunk in Forests, vol 8 n° 11 (November 2017)
[article]
Titre : An examination of diameter density prediction with k-NN and airborne lidar Type de document : Article/Communication Auteurs : Jacob L. Strunk, Auteur ; Peter J. Gould, Auteur ; Petteri Packalen, Auteur ; Krishna P. Poudel, Auteur ; Hans-Erik Andersen, Auteur ; Hailemariam Temesgen, Auteur Année de publication : 2017 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Caroline du Sud (Etats-Unis)
[Termes IGN] classification barycentrique
[Termes IGN] classification par la distance de Mahalanobis
[Termes IGN] diamètre des arbres
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] lasergrammétrie
[Vedettes matières IGN] Inventaire forestierRésumé : (Auteur) While lidar-based forest inventory methods have been widely demonstrated, performances of methods to predict tree diameters with airborne lidar (lidar) are not well understood. One cause for this is that the performance metrics typically used in studies for prediction of diameters can be difficult to interpret, and may not support comparative inferences between sampling designs and study areas. To help with this problem we propose two indices and use them to evaluate a variety of lidar and k nearest neighbor (k-NN) strategies for prediction of tree diameter distributions. The indices are based on the coefficient of determination (R2), and root mean square deviation (RMSD). Both of the indices are highly interpretable, and the RMSD-based index facilitates comparisons with alternative (non-lidar) inventory strategies, and with projects in other regions. K-NN diameter distribution prediction strategies were examined using auxiliary lidar for 190 training plots distribute across the 800 km2 Savannah River Site in South Carolina, USA. We evaluate the performance of k-NN with respect to distance metrics, number of neighbors, predictor sets, and response sets. K-NN and lidar explained 80% of variability in diameters, and Mahalanobis distance with k = 3 neighbors performed best according to a number of criteria Numéro de notice : A2017-877 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/f8110444 Date de publication en ligne : 16/11/2017 En ligne : https://doi.org/10.3390/f8110444 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91213
in Forests > vol 8 n° 11 (November 2017)[article]Mapping the height and spatial cover of features beneath the forest canopy at small-scales using airborne scanning discrete return Lidar / Matthew Sumnall in ISPRS Journal of photogrammetry and remote sensing, vol 133 (November 2017)
[article]
Titre : Mapping the height and spatial cover of features beneath the forest canopy at small-scales using airborne scanning discrete return Lidar Type de document : Article/Communication Auteurs : Matthew Sumnall, Auteur ; Thomas R. Fox, Auteur ; Randolph H. Wynne, Auteur ; Valerie A. Thomas, Auteur Année de publication : 2017 Article en page(s) : pp 186 - 200 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] couvert forestier
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] estimation statistique
[Termes IGN] Etats-Unis
[Termes IGN] hauteur des arbres
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] lidar à retour d'onde complète
[Termes IGN] Pinophyta
[Termes IGN] Pinus taeda
[Termes IGN] sous-boisRésumé : (Auteur) The objective of the current study was to develop methods for estimating the height and horizontal coverage of the forest understorey using airborne Lidar data in three managed pine plantation forest typical of the south eastern USA. The current project demonstrates a two-step approach applied automatically across a given study site extent. The first operation divided the study site extent into a regularly spaced grid (25 × 25 m) and identified the potential height range of the main Loblolly pine canopy layer for each grid-cell through aggregating Lidar return height measurements into a ‘stack’ of vertical height bins describing the frequency of returns by height. Once height bins were created, the resulting vertical distributions were smoothed with a regression curve line function and the main canopy vertical layer was identified through the detection of local maxima and minima. The second operation sub-divided the 25 × 25 m grid-cell into 1 × 1 m horizontal grid, for which height-bin stacks were created for each cell. Vertical features below the main canopy were then identified at this scale in the same manner as in the previous step, and classified as understorey features if they were lower in height than the 25 × 25 m estimate of the main canopy layer. The heights of the tallest understorey and sub-canopy layers were kept, and used to produce a rasterized map of the understorey layer height at the 1 × 1 m scale. Lidar derived estimates of the 25 × 25 m lowest vertical extent of the coniferous canopy correlated highly with field data (R2 0.87; RMSE 2.1 m). Estimates of understorey horizontal cover ranged from R2 0.80 to 0.90 (RMSE 6.6–11.7%), and maximum understorey layer height ranged from R2 0.69 to 0.80 (RMSE 1.6–3.4 m) for the three study sites. The automated method deployed within the current study proved sufficient in determining the presence and absence of vegetation and artificial structures within the understorey portion of the current forest context, in addition to height and horizontal cover to a reasonable accuracy. Issues were encountered within older stands (e.g. more than 30 years old) where understorey deciduous vegetation layers intersected with the coniferous canopy layer, resulting in an underestimation of sub-dominant heights. Numéro de notice : A2017-726 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2017.10.002 En ligne : https://doi.org/10.1016/j.isprsjprs.2017.10.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88411
in ISPRS Journal of photogrammetry and remote sensing > vol 133 (November 2017) . - pp 186 - 200[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2017111 RAB Revue Centre de documentation En réserve L003 Disponible 081-2017112 DEP-EAF Revue Nancy Dépôt en unité Exclu du prêt 081-2017113 DEP-EXM Revue Saint-Mandé Dépôt en unité Exclu du prêt Tree species classification using within crown localization of waveform LiDAR attributes / Rosmarie Blomley in ISPRS Journal of photogrammetry and remote sensing, vol 133 (November 2017)
[article]
Titre : Tree species classification using within crown localization of waveform LiDAR attributes Type de document : Article/Communication Auteurs : Rosmarie Blomley, Auteur ; Aarne Hovi, Auteur ; Martin Weinmann, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 142 - 156 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie
[Termes IGN] analyse multiéchelle
[Termes IGN] Betula pendula
[Termes IGN] betula pubescens
[Termes IGN] croissance des arbres
[Termes IGN] données lidar
[Termes IGN] données localisées 3D
[Termes IGN] espèce végétale
[Termes IGN] extraction de traits caractéristiques
[Termes IGN] forêt boréale
[Termes IGN] Norvège
[Termes IGN] Picea abies
[Termes IGN] Pinus sylvestris
[Termes IGN] rotation d'objetRésumé : (Auteur) Since forest planning is increasingly taking an ecological, diversity-oriented perspective into account, remote sensing technologies are becoming ever more important in assessing existing resources with reduced manual effort. While the light detection and ranging (LiDAR) technology provides a good basis for predictions of tree height and biomass, tree species identification based on this type of data is particularly challenging in structurally heterogeneous forests. In this paper, we analyse existing approaches with respect to the geometrical scale of feature extraction (whole tree, within crown partitions or within laser footprint) and conclude that currently features are always extracted separately from the different scales. Since multi-scale approaches however have proven successful in other applications, we aim to utilize the within-tree-crown distribution of within-footprint signal characteristics as additional features. To do so, a spin image algorithm, originally devised for the extraction of 3D surface features in object recognition, is adapted. This algorithm relies on spinning an image plane around a defined axis, e.g. the tree stem, collecting the number of LiDAR returns or mean values of returns attributes per pixel as respective values. Based on this representation, spin image features are extracted that comprise only those components of highest variability among a given set of library trees. The relative performance and the combined improvement of these spin image features with respect to non-spatial statistical metrics of the waveform (WF) attributes are evaluated for the tree species classification of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and Silver/Downy birch (Betula pendula Roth/Betula pubescens Ehrh.) in a boreal forest environment. This evaluation is performed for two WF LiDAR datasets that differ in footprint size, pulse density at ground, laser wavelength and pulse width. Furthermore, we evaluate the robustness of the proposed method with respect to internal parameters and tree size. The results reveal, that the consideration of the crown-internal distribution of within-footprint signal characteristics captured in spin image features improves the classification results in nearly all test cases Numéro de notice : A2017-724 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2017.08.013 En ligne : https://doi.org/10.1016/j.isprsjprs.2017.08.013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=88409
in ISPRS Journal of photogrammetry and remote sensing > vol 133 (November 2017) . - pp 142 - 156[article]Réservation
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Code-barres Cote Support Localisation Section Disponibilité 081-2017111 RAB Revue Centre de documentation En réserve L003 Disponible 081-2017112 DEP-EAF Revue Nancy Dépôt en unité Exclu du prêt 081-2017113 DEP-EXM Revue Saint-Mandé Dépôt en unité Exclu du prêt Adapter les itinéraires sylvicoles pour atténuer les effets du changement climatique. Résultats pour la chênaie sessiliflore française à partir des réseaux d’expérimentations sylvicoles / François Lebourgeois in Revue forestière française, vol 69 n° 1 (octobre 2017)PermalinkHyperspectral UAV-imagery and photogrammetric canopy height model in estimating forest stand variables / Sakari Tuominen in Silva fennica, vol 51 n° 5 (2017)PermalinkQuelle est la fiabilité de l’estimation visuelle des catégories de diamètre lors des descriptions des peuplements ? / Sylvain Gaudin in Revue forestière française, vol 69 n° 1 (octobre 2017)PermalinkSignificant effect of topographic normalization of airborne LiDAR data on the retrieval of plant area index profile in mountainous forests / Jing Liu in ISPRS Journal of photogrammetry and remote sensing, vol 132 (October 2017)PermalinkStand-volume estimation from multi-source data for coppiced and high forest Eucalyptus spp. silvicultural systems in KwaZulu-Natal, South Africa / Timothy Dube in ISPRS Journal of photogrammetry and remote sensing, vol 132 (October 2017)PermalinkStrong gradients in forest sensitivity to climate change revealed by dynamics of forest fire cycles in the post Little Ice Age Era / Igor Drobyshev in Journal of geophysical research : Biogeosciences, vol 122 n° 10 (October 2017)PermalinkTree size thresholds produce biased estimates of forest biomass dynamics / Eric B. Searle in Forest ecology and management, vol 400 (15 September 2017)PermalinkCrown bulk density and fuel moisture dynamics in Pinus pinaster stands are neither modified by thinning nor captured by the Forest Fire Weather Index / Marc Soler Martin in Annals of Forest Science, vol 74 n° 3 (September 2017)PermalinkForest canopy height estimation using satellite laser altimetry : a case study in the Western Ghats, India / S.M. Ghosh in Applied geomatics, vol 9 n° 3 (September 2017)PermalinkA Markov chain model for simulating wood supply from any-aged forest management based on national forest inventory (NFI) data / Jari Vauhkonen in Forests, vol 8 n° 9 (September 2017)Permalink