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A novel method for separating woody and herbaceous time series / Qiang Zhou in Photogrammetric Engineering & Remote Sensing, PERS, vol 85 n° 7 (July 2019)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 85 n° 7 (July 2019) . - pp 509 - 520 Titre : A novel method for separating woody and herbaceous time series Type de document : Article/Communication Auteurs : Qiang Zhou, Auteur ; Shuguang Liu, Auteur ; Michael J Hill, Auteur Année de publication : 2019 Article en page(s) : pp 509 - 520 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] Afrique australe [Termes IGN] bois [Termes IGN] extraction de la végétation [Termes IGN] image à haute résolution [Termes IGN] image Ikonos [Termes IGN] image Landsat-SWIR [Termes IGN] image Terra-MODIS [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] plante herbacée [Termes IGN] savane [Termes IGN] série temporelle [Termes IGN] variation saisonnière Résumé : (auteur) Mapping the spatial distribution of woody and herbaceous vegetation in high temporal resolution in savannas would be beneficial for modeling interrelationships between trees and grasses, and monitoring fuel loads and biomass for livestock. In this study, we developed a frequency decomposition method to separate woody and herbaceous vegetation components using Normalized Difference Vegetation Index (NDVI) time series. The results were validated using fractional cover data derived from high-resolution images. The validation revealed a close relationship between our decomposed NDVI and corresponding fractional cover (R2 = 0.55 and 0.64 for woody and herbaceous components, respectively). We examined the spatial and temporal patterns of the decomposed NDVI, where woody and herbaceous NDVI showed different responses to precipitation. The methods proposed in this study can be used to separate the woody and herbaceous NDVI time series as an alternative approach for monitoring woody and herbaceous vegetation interrelationships related to climatic drivers. Numéro de notice : A2019-259 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.14358/PERS.85.7.509 Date de publication en ligne : 01/07/2019 En ligne : https://doi.org/10.14358/PERS.85.7.509 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=93062 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
105-2019071	SL	Revue	Centre de documentation	Revues en salle	Disponible

Above-ground and below-ground competition between the willow Salix caprea and its understorey / Ondřej Mudrák in Journal of vegetation science, vol 27 n° 1 (January 2016)  

Public [article]  inJournal of vegetation science > vol 27 n° 1 (January 2016) . - pp 156 - 164 Titre : Above-ground and below-ground competition between the willow Salix caprea and its understorey Type de document : Article/Communication Auteurs : Ondřej Mudrák, Auteur ; Markéta Hermová, Auteur ; Cecilie Tesnerová, Auteur ; Jana Rydlová, Auteur ; Jan Frouz, Auteur Année de publication : 2016 Article en page(s) : pp 156 - 164 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] composition floristique [Termes IGN] mine [Termes IGN] plante herbacée [Termes IGN] République Tchèque [Termes IGN] Salix caprea [Termes IGN] sous-bois [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) Questions : Has the observed decline in the willow Salix caprea L., one of the most common colonizers of post-mining sites in Central Europe, contributed to changes in the rest of the plant community on post-mining sites? How does S. caprea modify its understorey? How is the understorey vegetation affected by above-ground and below-ground competition with S. caprea? Location : Heaps after coal mining near Sokolov, Czech Republic (50°14′21″ N, 12°40′45″ E). Methods : The effects of above-ground and below-ground competition with the willow S. caprea on its understorey plant community were studied in un-reclaimed post-mining sites. Below-ground competition was evaluated by comparing (1) frames inserted into the soil that excluded woody roots (frame treatment), (2) frames that initially excluded woody root growth but then allowed regrowth of the roots (open-frame treatment), and (3) undisturbed soil (no-frame treatment). These treatments were combined with S. caprea thinning to assess the effect of above-ground competition. Results : Three years after the start of the experiment, above-ground competition from S. caprea (as modified by thinning of the S. caprea canopy) had not affected understorey biomass or species number, but had affected species composition. In contrast, below-ground competition significantly affected both the above-ground and below-ground biomass of the understorey. The above-ground biomass of the understorey was larger in the frame treatment (which excluded woody roots) than in the other two treatments. The below-ground biomass of the understorey was larger in the frame than in the open-frame treatment. Unlike above-ground competition (light availability), below-ground competition did not affect understorey species composition. Conclusions : Our results suggest that S. caprea is an important component during plant succession on post-mining sites because it considerably modifies its understorey plant community. Below-ground competition is a major reason for the low cover and biomass of the herbaceous understorey in S. caprea stands on post-mining sites. Numéro de notice : A2016-362 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.1111/jvs.12330 En ligne : http://dx.doi.org/10.1111/jvs.12330 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81099 [article]

Une strate herbacée monopoliste : quelle concurrence vis-à-vis de l’eau pour le peuplement adulte ? / Rémy Gobin in Rendez-vous techniques, n° 48-49 (été automne 2015) 

Public [article]  inRendez-vous techniques > n° 48-49 (été automne 2015) . - pp 17 - 22 Titre : Une strate herbacée monopoliste : quelle concurrence vis-à-vis de l’eau pour le peuplement adulte ? Type de document : Article/Communication Auteurs : Rémy Gobin, Auteur ; Philippe Balandier, Auteur ; Nathalie Korboulewsky, Auteur ; Yann Dumas, Auteur ; Vincent Seigner, Auteur ; Claudine Richter, Auteur Année de publication : 2016 Article en page(s) : pp 17 - 22 Note générale : bibliographie Langues : Français (fre) Descripteur : [Termes IGN] peuplement forestier [Termes IGN] plante herbacée [Termes IGN] sous-bois [Termes IGN] stress hydrique [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) L’adaptation des forêts aux changements climatiques est un enjeu crucial pour l’avenir. Sachant que, dans bien des cas, il faudra faire face à un problème de disponibilité en eau, une des stratégies consisterait à diminuer la densité des peuplements forestiers pour limiter le stress hydrique. Mais si, profitant de la réduction du couvert arboré, la strate herbacée explosait et exacerbait la concurrence ? Où placer le curseur ? Deux expérimentations d’Irstea donnent quelques indications pour les espèces du sous-bois dites monopolistes. Numéro de notice : A2015--008 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=80582 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
IFN-001-P001791	PER	Revue	Nogent-sur-Vernisson	Salle périodiques	Exclu du prêt

Documents numériques

en open access Une strate herbacée monopoliste Adobe Acrobat PDF

Small-footprint Lidar estimations of sagebrush canopy characteristics / J. Mitchell in Photogrammetric Engineering & Remote Sensing, PERS, vol 77 n° 5 (May 2011)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 77 n° 5 (May 2011) . - pp 521 - 530 Titre : Small-footprint Lidar estimations of sagebrush canopy characteristics Type de document : Article/Communication Auteurs : J. Mitchell, Auteur ; N. Glenn, Auteur ; et al., Auteur Année de publication : 2011 Article en page(s) : pp 521 - 530 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] arbuste [Termes IGN] densité des points [Termes IGN] données lidar [Termes IGN] données maillées [Termes IGN] hauteur de la végétation [Termes IGN] plante herbacée [Termes IGN] semis de points Résumé : (Auteur) The height and shape of shrub canopies are critical measurements for characterizing shrub steppe rangelands. Remote sensing technologies might provide an efficient method to acquire these measurements across large areas. This study compared point-cloud and rasterized lidar data to field-measured sagebrush height and shape to quantify the correlation between field-based and lidar-derived estimates. The results demonstrated that discrete return, small-footprint lidar with high point density (9.46 points/m2) can provide strong predictions of true sagebrush height (H2 of 0.84 to 0.86), but with a consistent underestimation of approximately 30 percent. Our results provided the first successful lidar-based descriptors of sagebrush shape with R2 values of 0.65, 0.74, and 0.78 for respective predictions of shortest canopy diameter, longest canopy diameter, and canopy area. Future studies can extend lidar-derived shrub height and shape measurements to canopy volume, cover, and biomass estimates. Numéro de notice : A2011-171 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.77.5.521 En ligne : https://doi.org/10.14358/PERS.77.5.521 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30949 [article]

Effects of selective thinning on growth and development of beech (Fagus sylvatica L.) forest stands in south-eastern Slovenia / Andrej Boncina in Annals of Forest Science, vol 64 n° 1 (January 2007)  

Public [article]  inAnnals of Forest Science > vol 64 n° 1 (January 2007) . - pp 47 - 57 Titre : Effects of selective thinning on growth and development of beech (Fagus sylvatica L.) forest stands in south-eastern Slovenia Type de document : Article/Communication Auteurs : Andrej Boncina, Auteur ; Ales Kadunc, Auteur ; Dusan Robic, Auteur Année de publication : 2007 Article en page(s) : pp 47 - 57 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] biodiversité végétale [Termes IGN] éclaircie (sylviculture) [Termes IGN] Fagus sylvatica [Termes IGN] peuplement forestier [Termes IGN] plante herbacée [Termes IGN] Slovénie [Termes IGN] sylviculture [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) We studied the effects of two types of selective thinning on beech stands formed by a shelterwood cut in 1910 — with lower number of crop trees and higher thinning intensity (T1) and higher number of crop trees with lower thinning intensity (T2). The stands were thinned in 1980, 1991 and 2001. Despite a lower stand density after thinning, the annual basal area increments of thinned stands in both thinning periods (1980–1991 and 1991–2002) were around 20% higher compared to those of the control (unthinned) stands. The mean annual basal area increment of dominant trees was 30–56% larger in the thinned plots compared to the control plots. Of 176 initial crop trees in the T1, 72% were chosen again during the last thinning. In the T2, 258 crop trees were chosen in the first thinning, and only 62% of these trees were chosen again during the last thinning. Only crown suppression and diameter classes of crop trees significantly influenced their basal area increment when diameter classes, crown size, crown suppression, and social status were tested. In the thinned stands, the dominant trees are more uniformly distributed if compared to the dominant trees in the control plots. Finally, the herbaceous cover and the species diversity were higher in the thinned plots. Numéro de notice : A2007-040 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1051/forest:2006087 Date de publication en ligne : 16/01/2007 En ligne : https://www.afs-journal.org/articles/forest/abs/2007/01/f7005/f7005.html Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81119 [article]