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Decreasing stand density favors resistance, resilience, and recovery of Quercus petraea trees to a severe drought, particularly on dry sites / Anna Schmitt in Annals of Forest Science, Vol 77 n° 2 (June 2020)
[article]
Titre : Decreasing stand density favors resistance, resilience, and recovery of Quercus petraea trees to a severe drought, particularly on dry sites Type de document : Article/Communication Auteurs : Anna Schmitt, Auteur ; Raphaël Trouvé, Auteur ; Ingrid Seynave, Auteur ; François Lebourgeois, Auteur Année de publication : 2020 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] bilan hydrique
[Termes IGN] densité de la végétation
[Termes IGN] peuplement forestier
[Termes IGN] Quercus sessiliflora
[Termes IGN] résilience écologique
[Termes IGN] sécheresse
[Termes IGN] sylviculture
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) Key message: Decreasing stand density increases resistance, resilience, and recovery of Quercus petraea trees to severe drought (2003), particularly on dry sites, and the effect was independent of tree social status. Context: Controlling competition is an advocated strategy to modulate the response of trees to predicted changes in climate. Aims: We investigated the effects of stand density (low, medium, high; relative density index 0.20, 0.53, 1.04), social status (dominant, codominant, suppressed), and water balance (dry, mesic, wet; summer water balance − 182, − 126, − 96 mm) on the climate-growth relationships (1997–2012) and resistance (Rt), resilience (Rs), and recovery (Rc) following the 2003 drought. Methods: Basal area increments were collected by coring (269 trees) in young stands (28 ± 7.5 years in 2012) of sessile oak (Quercus petraea) in a French permanent network of silvicultural plots. Results: We showed that the climate-growth relationships depend on average site-level water balance with trees highly dependent on spring and summer droughts on dry and mesic sites and not at all on wet sites. Neither stand density nor social status modulated mean response to climate. Decreasing stand density increased Rt, Rs, and Rc particularly on dry sites. The effect was independent of tree social position within the stand. Conclusion: Reducing stand density mitigates more the effect of extreme drought events on drier sites than on wet sites. Numéro de notice : A2020-292 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-020-00959-9 Date de publication en ligne : 26/05/2020 En ligne : https://doi.org/10.1007/s13595-020-00959-9 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95122
in Annals of Forest Science > Vol 77 n° 2 (June 2020)[article]Size-class structure of the forests of Finland during 1921–2013: a recovery from centuries of exploitation, guided by forest policies / Helena M. Henttonen in European Journal of Forest Research, vol 139 n° 2 (April 2020)
[article]
Titre : Size-class structure of the forests of Finland during 1921–2013: a recovery from centuries of exploitation, guided by forest policies Type de document : Article/Communication Auteurs : Helena M. Henttonen, Auteur ; Pekka Nöjd, Auteur ; Susanne Suvanto, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 279 – 293 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] analyse diachronique
[Termes IGN] brûlis
[Termes IGN] densité de la végétation
[Termes IGN] diamètre à hauteur de poitrine
[Termes IGN] échantillonnage de données
[Termes IGN] Finlande
[Termes IGN] forêt boréale
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] paturage
[Termes IGN] peuplement forestier
[Termes IGN] Picea abies
[Termes IGN] Pinus sylvestris
[Termes IGN] politique forestière
[Termes IGN] sylviculture
[Termes IGN] utilisation du sol
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Frequency distributions of tree diameters are a powerful tool for analyzing changes of tree populations in large areas. We analyzed the densities and mean volume estimates of trees in different size classes for the Finnish forests over the time-span of the National Forest Inventories (1921–2013). The results display a general increase in trees in all size classes, species group and geographical area, mainly after the 1970s. The densities of medium- and large-sized conifers showed large increases in the southern boreal subzone, spruces even more than pines. Small- to medium-sized pines have increased in the middle and northern boreal subzones. The shifts in growing stock are related to changing land use, resulting from the development of the society. The low quantities of both growing stock and large trees during the 1920s reflect a poor initial state of forests. Several land use forms of the former agriculture-based society were detrimental to forests, including slash and burn agriculture, cattle grazing and tar production. The pressure from alternative land use forms was stronger in southern Finland, where the population density (people per km2) is much higher. Between 1971 and 2013, the changes in size-class structure can be attributed mainly to intensified silviculture boosted by actions of the Finnish governments, including both legislation and financial support for management activities. Not only the development of growing stock has exceeded expectations, but the increase has also concentrated in the economically valuable trees in the large size classes. Numéro de notice : A2020-344 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s10342-019-01241-y Date de publication en ligne : 27/11/2019 En ligne : https://doi.org/10.1007/s10342-019-01241-y Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95224
in European Journal of Forest Research > vol 139 n° 2 (April 2020) . - pp 279 – 293[article]Efficiency of post-stratification for a large-scale forest inventory : case Finnish NFI / Helena Haakana in Annals of Forest Science, vol 76 n° 1 (March 2019)
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Titre : Efficiency of post-stratification for a large-scale forest inventory : case Finnish NFI Type de document : Article/Communication Auteurs : Helena Haakana, Auteur ; Juha Heikkinen, Auteur ; Matti Katila, Auteur ; Annika S. Kangas, Auteur Année de publication : 2019 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] carte de la végétation
[Termes IGN] densité de la végétation
[Termes IGN] Finlande
[Termes IGN] image Landsat
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] inventaire forestier étranger (données)
[Termes IGN] ressources forestières
[Termes IGN] stratification
[Termes IGN] volume en bois
[Vedettes matières IGN] Inventaire forestierRésumé : (auteur) Key message : Post-stratification based on remotely sensed data is an efficient method in estimating regional-level results in the operational National Forest Inventory. It also enables calculating the results accurately for smaller areas than with the default method of using the field plots only.
Context : The utilization of auxiliary information in survey sampling through model-assisted estimation or post-stratification has gained popularity in forest inventory recently. However, post-stratification at a large scale involves practical concerns such as the availability of auxiliary data independent of the sample at hand, and a large number of variables for which the results are needed.
Aims : We assessed the efficiency of two different types of post-stratification, either post-stratifying for each variable of interest separately or using one post-stratification for all variables, compared to the estimation based on the field sample plots only. In addition, we examined the precision of area and volume estimates, and the efficiency of post-stratification at different spatial scales.
Methods : For post-stratification, we used the volume maps based on Landsat satellite imagery, digital map data, and the sample plot data of the previous inventory. The efficiencies of post-stratifications based on the mean volume and the mean volumes by tree species were compared.
Results : In estimating the total volume, the relative efficiency of post-stratification compared to field plot based estimation was 1.54–3.54 over the provinces in South Finland. In estimating the volumes by tree species groups, the relative efficiency was 0.93–2.39. The gain with a separate stratification compared to the stratification based on total mean volume for all variables was at largest 0.69. In the small test areas, the relative standard errors of the total volume estimates decreased on average by 33% by using post-stratification instead of sample plots only. The mean relative efficiency was 2.36.
Conclusion : The utilization of an old forest resources map and post-stratification based on the mean volume is an operational approach for the National Forest Inventory. Post-stratification also enables calculating the results accurately for markedly smaller areas than with the field plots only. Post-stratification reduced the probability of very high sampling variances, making the results more robust.Numéro de notice : A2019-042 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-018-0795-6 Date de publication en ligne : 30/01/2019 En ligne : https://doi.org/10.1007/s13595-018-0795-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92040
in Annals of Forest Science > vol 76 n° 1 (March 2019)[article]When do dendrometric rules fail? Insights from 20 years of experimental thinnings on sessile oak in the GIS Coop network / Raphaël Trouvé in Forest ecology and management, vol 433 (15 February 2019)
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Titre : When do dendrometric rules fail? Insights from 20 years of experimental thinnings on sessile oak in the GIS Coop network Type de document : Article/Communication Auteurs : Raphaël Trouvé, Auteur ; Jean-Daniel Bontemps , Auteur ; Catherine Collet, Auteur ; Ingrid Seynave, Auteur ; François Lebourgeois, Auteur Année de publication : 2019 Projets : ORACLE/Changements Environnementaux Planétaires & Sociétés (CEP&S) / Noblet-Ducoudré, Nathalie de Article en page(s) : pp 276-286 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] croissance des arbres
[Termes IGN] dendrométrie
[Termes IGN] densité de la végétation
[Termes IGN] productivité
[Termes IGN] Quercus sessiliflora
[Vedettes matières IGN] Végétation et changement climatiqueRésumé : (auteur) Context : Lowering stand density has been suggested to adapt forests to warmer and drier conditions. Whether common dendrometric rules used to guide growth models and support silviculture are still valid at these densities lower than usual needs be tested. This includes (1) estimating the stand growth-density relationship over wider density gradients (‘Langsaeter’s rule’), (2) testing the stability of site index, and (3) ‘Eichhorn’s rule’ (relating site index to stand growth) at lower densities. Additionally, environmental changes call for a more direct inclusion of environmental drivers in growth models.
Material and methods : We investigated the effects of relative stand density (RDI) on stand growth of even-aged stands of sessile oak. We also analyzed effects of climatic conditions to assess whether sessile oak is already at a critical stage that requires adapting forest management. We used a network of silvicultural trials designed to test the effects of maximum density gradients on stand dynamics along climatic gradients.
Results : As predicted by Langsaeter’s rule, gross stand growth increased with RDI then saturated for RDI > 0.4–0.5, mortality began after crown closure, and diameter increment decreased non-linearly with RDI. Dominant height growth first increased with RDI then saturated for RDI > 0.8. Positive effects of RDI on both stand and height growth caused Eichhorn’s rule to be stable over a large range of RDI (0.25–1). Effects of climate predictors were weak and only visible for radial growth indices. They however suggested antagonistic effects of water and temperature constraints in summer and autumn.
Discussion : Langsaeter’s and Eichhorn’s rules were found valid over a large range of RDI values. We suggest using them to guide growth models and management. However, assumptions behind the use of site index as a proxy for stand productivity were invalidated. Weak and opposed effect of temperature in summer and autumn makes the outcome of climate warming on sessile oak growth uncertain.Numéro de notice : A2019-001 Affiliation des auteurs : LIF+Ext (2012-2019) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.foreco.2018.11.007 Date de publication en ligne : 17/11/2018 En ligne : https://doi.org/10.1016/j.foreco.2018.11.007 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91406
in Forest ecology and management > vol 433 (15 February 2019) . - pp 276-286[article]TanDEM-X digital surface models in boreal forest above-ground biomass change detection / Kirsi Karila in ISPRS Journal of photogrammetry and remote sensing, vol 148 (February 2019)
[article]
Titre : TanDEM-X digital surface models in boreal forest above-ground biomass change detection Type de document : Article/Communication Auteurs : Kirsi Karila, Auteur ; Xiaowei Yu, Auteur ; Mikko Vastaranta, Auteur ; et al., Auteur Année de publication : 2019 Article en page(s) : pp 174 - 183 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications
[Termes IGN] biomasse aérienne
[Termes IGN] biomasse forestière
[Termes IGN] densité de la végétation
[Termes IGN] détection de changement
[Termes IGN] données localisées 3D
[Termes IGN] Finlande
[Termes IGN] forêt boréale
[Termes IGN] hauteur des arbres
[Termes IGN] interféromètrie par radar à antenne synthétique
[Termes IGN] inventaire forestier (techniques et méthodes)
[Termes IGN] MNS TerraSAR & TanDEM-X
[Termes IGN] modèle numérique de surfaceRésumé : (Auteur) Satellite images provide spatially explicit information on forest change covering wide areas. In this study, bistatic TanDEM-X (TDX) synthetic aperture radar (SAR) satellite data were used to derive digital surface models (DSMs) of forest areas using SAR interferometry (InSAR). The capability of change features derived from bi-temporal InSAR DSMs to detect forest height (90th percentile of canopy height distribution, H90) and density variations was investigated. Moreover, changes in the forest above-ground biomass (AGB) were estimated from height changes between two InSAR DSMs. Bi-temporal airborne laser scanning (ALS) data, aerial orthoimages and an ALS-based AGB change map from a study area in Southern Finland were used as references. The results indicate that the InSAR height change of a forested area correlates more with vegetation density change than with height change. The correlation between the InSAR mean height change and the height change feature from ALS was 0.76 at stand level. Correspondingly, the correlation between the InSAR mean height change and the ALS penetration rate change was 0.89. The AGB changes predicted based on InSAR height change agreed well with the reference data; the root-mean-square error (RMSE) was 20.7 Mg/ha (18.5% of the mean biomass in 2012) at stand level and 27.4 Mg/ha (27.0%) for 16 × 16 m grid cells. The results show that TDX DSMs can be used to detect biomass changes of different orders of magnitude, e.g. due to logging and thinning. Numéro de notice : A2019-073 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2019.01.002 Date de publication en ligne : 11/01/2019 En ligne : https://doi.org/10.1016/j.isprsjprs.2019.01.002 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92160
in ISPRS Journal of photogrammetry and remote sensing > vol 148 (February 2019) . - pp 174 - 183[article]Exemplaires(3)
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