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Taller and slenderer trees in Swedish forests according to data from the National Forest Inventory / Alex Appiah Mensah in Forest ecology and management, vol 527 (January-1 2023)  

Public [article]  inForest ecology and management > vol 527 (January-1 2023) . - n° 120605 Titre : Taller and slenderer trees in Swedish forests according to data from the National Forest Inventory Type de document : Article/Communication Auteurs : Alex Appiah Mensah, Auteur ; Hans Petersson, Auteur ; Jonas Dahlgren, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : n° 120605 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] azote [Termes IGN] changement climatique [Termes IGN] diamètre à hauteur de poitrine [Termes IGN] forêt boréale [Termes IGN] gestion forestière [Termes IGN] hauteur des arbres [Termes IGN] inventaire forestier étranger (données) [Termes IGN] Picea abies [Termes IGN] Pinus sylvestris [Termes IGN] Suède [Termes IGN] surface terrière [Vedettes matières IGN] Inventaire forestier Résumé : (auteur) Changes over time in annual basal area growth and mean height for Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) over the period, 1983–2020 were studied using sample tree data from temporary plots recorded in the Swedish National Forest Inventory. The annual basal area growth was derived from the last measured full ring on increment cores. Using 20 to 60-year-old dominant trees, the mean height and annual basal area growth were examined as functions of tree, stand and site conditions, and trends were assessed mainly using residual analyses over time. A significant increase in mean height at a given age was found for both species, but the annual basal area growth level remained stable over the 38-year period. Currently, at a given age of 50 annual rings at breast height, the mean heights of pines and spruces increased on average by 10.1% (i.e. ∼2 m), compared to 50 year-old pines and spruces in the 1980s, and the increase was similar in the different regions. The results suggest that trees have become taller and slenderer in Swedish forests. Increasing tree height over time at a given age in Northern Europe has been documented in several reports and many causes have been suggested, such as changed forest management, increasing temperatures and nitrogen deposition. We suggest that elevated CO2 in the air and improved water-use efficiency for the trees might also be strong drivers. Numéro de notice : A2023-005 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1016/j.foreco.2022.120605 Date de publication en ligne : 05/11/2022 En ligne : https://doi.org/10.1016/j.foreco.2022.120605 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102008 [article]

The contribution of understorey vegetation to ecosystem evapotranspiration in boreal and temperate forests: a literature review and analysis / Philippe Balandier in European Journal of Forest Research, vol 141 n° 6 (December 2022)  

Public [article]  inEuropean Journal of Forest Research > vol 141 n° 6 (December 2022) . - pp 979 - 997 Titre : The contribution of understorey vegetation to ecosystem evapotranspiration in boreal and temperate forests: a literature review and analysis Type de document : Article/Communication Auteurs : Philippe Balandier, Auteur ; Rémy Gobin, Auteur ; Bernard Prévosto, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : pp 979 - 997 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] bilan hydrique [Termes IGN] écosystème forestier [Termes IGN] évapotranspiration [Termes IGN] forêt boréale [Termes IGN] forêt tempérée [Termes IGN] gestion forestière [Termes IGN] Leaf Area Index [Termes IGN] phénologie [Termes IGN] sous-bois [Termes IGN] sous-étage [Termes IGN] structure d'un peuplement forestier [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) In the context of increasing heat periods and recurrence of droughts, and thus higher soil water depletion, we explored and quantified the role of understorey vegetation in ecosystem evapotranspiration in boreal and temperate forests. We reviewed and analysed about 200 papers that explicitly gave figures of understorey vegetation evapotranspiration relative to different stand features and traits. Understorey vegetation accounted on average for one-third of total ecosystem evapotranspiration during the growing season. Overstorey leaf area index (LAI) is the main variable that drives understorey evapotranspiration through radiation interception. Most data show that below an overstorey LAI of 2–3, the contribution of the understorey vegetation to ecosystem evapotranspiration increases exponentially, following the exponential increase of the climatic demand, i.e. potential evapotranspiration. Different factors have the potential to modulate this effect such as species composition and phenology, root distribution, and interaction with droughts. Consequently, managers must be aware that depending on understorey species present on site and stand structure, understorey vegetation can contribute significantly to a negative stand water balance. Numéro de notice : A2022-857 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s10342-022-01505-0 Date de publication en ligne : 10/10/2022 En ligne : https://doi.org/10.1007/s10342-022-01505-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102108 [article]

Effect of riparian soil moisture on bacterial, fungal and plant communities and microbial decomposition rates in boreal stream-side forests / M.J. Annala in Forest ecology and management, vol 519 (September-1 2022)  

Public [article]  inForest ecology and management > vol 519 (September-1 2022) . - n° 120344 Titre : Effect of riparian soil moisture on bacterial, fungal and plant communities and microbial decomposition rates in boreal stream-side forests Type de document : Article/Communication Auteurs : M.J. Annala, Auteur ; K. Lehosmaa, Auteur ; S.H.K. Ahonen, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 120344 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] cours d'eau [Termes IGN] écosystème forestier [Termes IGN] Finlande [Termes IGN] forêt boréale [Termes IGN] forêt ripicole [Termes IGN] Fungi [Termes IGN] humidité du sol [Termes IGN] micro-organisme [Termes IGN] plante ripicole [Termes IGN] taxinomie [Termes IGN] zone tampon [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) Riparian habitats of boreal forests are considered as hotspots for biochemical processes and biodiversity, and varying width riparian buffers have been proposed to protect species diversity of the riparian forests. However, evidence of the role of soil moisture variation in shaping riparian biodiversity and ecosystem functioning remain scarce particularly regarding belowground diversity. We studied how distance from the stream and soil moisture of the riparian zone affected species richness and community composition of plants, bacteria, and fungi as well as microbial decomposition rates. Using a split-plot design with a plant survey and amplicon sequencing for microorganisms we identified taxa associated with different categories of moisture and distance from the stream along six headwater stream-sides in middle boreal forests in Northern Finland. Tea-bag Index was used to assess the decomposition rates. PERMANOVA and linear mixed-effect models were used to analyze the data. Variation in riparian soil moisture influenced species composition and richness of plants and bacteria. Plant communities also changed from herbaceous dominated to shrub dominated with increasing distance from the stream. Fungal communities, however, did not respond to soil moisture or distance from the stream, and there were only slight differences in fungal trophic guilds among moisture and distance categories. Decomposition of organic material by microorganisms was faster adjacent to the stream than further away, and moist riparian areas had higher decomposition rates than drier ones. Decomposition rates were positively related to pH, Ca, Mg and NH4 and soil temperature. Synthesis and applications We show that above- and belowground diversity and microbial decomposition are associated to soil moisture at riparian sites supporting the idea of leaving wider unmanaged buffers in moist habitats to safeguard the overall forest diversity. Our findings further emphasize the need to consider soil moisture when planning the measures for riparian protection as changes in riparian soil moisture could lead to deterioration of organic matter decomposition. Different responses of the examined plant and microbial communities to riparian soil conditions clearly imply that overall riparian diversity cannot be explained based on a single community type, and that different organisms may respond differently to human-induced changes in stream riparian zone. Numéro de notice : A2022-485 Affiliation des auteurs : non IGN Thématique : BIODIVERSITE/FORET Nature : Article DOI : 10.1016/j.foreco.2022.120344 Date de publication en ligne : 04/06/2022 En ligne : https://doi.org/10.1016/j.foreco.2022.120344 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100923 [article]

Exploring tree growth allometry using two-date terrestrial laser scanning / Tuomas Yrttimaa in Forest ecology and management, vol 518 (August-15 2022)  

Public [article]  inForest ecology and management > vol 518 (August-15 2022) . - n° 120303 Titre : Exploring tree growth allometry using two-date terrestrial laser scanning Type de document : Article/Communication Auteurs : Tuomas Yrttimaa, Auteur ; Ville Luoma, Auteur ; Ninni Saarinen, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 120303 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] allométrie [Termes IGN] croissance des arbres [Termes IGN] diamètre à hauteur de poitrine [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] forêt boréale [Termes IGN] houppier [Termes IGN] semis de points [Termes IGN] série temporelle [Termes IGN] surface terrière [Termes IGN] volume en bois Résumé : (auteur) Tree growth is a physio-ecological phenomena of high interest among researchers across disciplines. Observing changes in tree characteristics has conventionally required either repeated measurements of the characteristics of living trees, retrospective measurements of destructively sampled trees, or modelling. The use of close-range sensing techniques such as terrestrial laser scanning (TLS) has enabled non-destructive approaches to reconstruct the three-dimensional (3D) structure of trees and tree communities in space and time. This study aims at improving the understanding of tree allometry in general and interactions between tree growth and its neighbourhood in particular by using two-date point clouds. We investigated how variation in the increments in basal area at the breast height (Δg1.3), basal area at height corresponding to 60% of tree height (Δg06h), and volume of the stem section below 50% of tree height (Δv05h) can be explained with TLS point cloud-based attributes characterizing the spatiotemporal structure of a tree crown and crown neighbourhood, entailing the competitive status of a tree. The analyses were based on 218 trees on 16 sample plots whose 3D characteristics were obtained at the beginning (2014, T1) and at the end of the monitoring period (2019, T2) from multi-scan TLS point clouds using automatic point cloud processing methods. The results of this study showed that, within certain tree communities, strong relationships (|r| > 0.8) were observed between increments in the stem dimensions and the attributes characterizing crown structure and competition. Most often, attributes characterizing the competitive status of a tree, and the crown structure at T1, were the most important attributes to explain variation in the increments of stem dimensions. Linear mixed-effect modelling showed that single attributes could explain up to 35–60% of the observed variation in Δg1.3, Δg06h and Δv05h, depending on the tree species. This tree-level evidence of the allometric relationship between stem growth and crown dynamics can further be used to justify landscape-level analyses based on airborne remote sensing technologies to monitor stem growth through the structure and development of crown structure. This study contributes to the existing knowledge by showing that laser-based close-range sensing is a feasible technology to provide 3D characterization of stem and crown structure, enabling one to quantify structural changes and the competitive status of trees for improved understanding of the underlying growth processes. Numéro de notice : A2022-484 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1016/j.foreco.2022.120303 Date de publication en ligne : 22/05/2022 En ligne : https://doi.org/10.1016/j.foreco.2022.120303 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100899 [article]

Direct and automatic measurements of stem curve and volume using a high-resolution airborne laser scanning system / Eric Hyyppä in Science of remote sensing, vol 5 (June 2022)  

Public [article]  inScience of remote sensing > vol 5 (June 2022) . - n° 100050 Titre : Direct and automatic measurements of stem curve and volume using a high-resolution airborne laser scanning system Type de document : Article/Communication Auteurs : Eric Hyyppä, Auteur ; Antero Kukko, Auteur ; Harri Kaartinen, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 100050 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] canopée [Termes IGN] détection d'arbres [Termes IGN] diamètre à hauteur de poitrine [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] Finlande [Termes IGN] forêt boréale [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] inventaire forestier local [Termes IGN] modèle de croissance végétale [Termes IGN] modèle numérique de terrain [Termes IGN] Picea abies [Termes IGN] semis de points [Termes IGN] volume en bois Résumé : (auteur) Today, high-quality reference tree measurements, including the position, diameter, height and volume, are cumbersome and slow to carry out, but highly needed for forest inventories based on airborne laser scanning. Mobile laser scanning technologies hold the promise for collecting reference data for forest inventories with an extremely high efficiency. Perhaps, the most efficient approach for reference data collection would be to mount a high-resolution laser scanning system on board an airborne vehicle flying at a low altitude above the forest canopy since this would allow recording reference samples of individual trees with the speed of flight. To demonstrate the potential of this technology, we mounted an in-house developed HeliALS-DW laser scanning system on board a helicopter and collected point cloud data in a boreal forest on three test sites containing a total of 1469 trees. The obtained point clouds incorporated sufficiently many high-quality stem hits for estimating the stem curves and stem volumes of individual trees since the point clouds had a relatively high point density of 2200–3800 echoes/m2, and the scanner had been tilted by 15° from the nadir to increase the possibility of recording stem hits. To automatically estimate the diameters at breast height (DBH) and stem curves of individual trees, we used algorithms designed to tolerate moderate drifts in the trajectory of the laser scanner. Furthermore, the stem volumes of individual trees were computed by using the estimated stem curves and tree heights without any allometric models. Using the proposed methods, we were able to estimate the stem curves with a root-mean-square error (RMSE) of 1.7–2.6 cm (6–9%) while detecting 42–71% of the trees. The RMSE of stem volume estimates was 0.1–0.15 m3 (12–21%). We also showed that the tree detection rate could be improved up to 87–96% for trees with a DBH exceeding 20 cm if slightly larger average errors for the stem attributes were allowed. Our results pave the way for using high-resolution airborne laser scanning for field reference data collection by conducting direct measurements of tree stems with a high efficiency. Numéro de notice : A2022-298 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1016/j.srs.2022.100050 Date de publication en ligne : 09/04/2022 En ligne : https://doi.org/10.1016/j.srs.2022.100050 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100464 [article]

Individual tree detection and estimation of stem attributes with mobile laser scanning along boreal forest roads / Raul de Paula Pires in ISPRS Journal of photogrammetry and remote sensing, vol 187 (May 2022)  

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Data assimilation of growing stock volume using a sequence of remote sensing data from different sensors / Niels Lindgren in Canadian journal of remote sensing, vol 48 n° 2 (April 2022)  

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Natural disturbances risks in European boreal and temperate forests and their links to climate change : A review of modelling approaches / Joyce Machado Nunes Romeiro in Forest ecology and management, vol 509 (April-1 2022)  

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PolGAN: A deep-learning-based unsupervised forest height estimation based on the synergy of PolInSAR and LiDAR data / Qi Zhang in ISPRS Journal of photogrammetry and remote sensing, vol 186 (April 2022)  

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Two-phase forest inventory using very-high-resolution laser scanning / Henrik J. Persson in Remote sensing of environment, vol 271 (March- 2 2022)  

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Towards low vegetation identification: A new method for tree crown segmentation from LiDAR data based on a symmetrical structure detection algorithm (SSD) / Langning Huo in Remote sensing of environment, vol 270 (March 2022)  

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Ultrahigh-resolution boreal forest canopy mapping: Combining UAV imagery and photogrammetric point clouds in a deep-learning-based approach / Linyuan Li in International journal of applied Earth observation and geoinformation, vol 107 (March 2022)  

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Characteristics of taiga and tundra snowpack in development and validation of remote sensing of snow / Henna-Reetta Hannula (2022)  

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A comparison of linear-mode and single-photon airborne LiDAR in species-specific forest inventories / Janne Raty in IEEE Transactions on geoscience and remote sensing, vol 60 n° 1 (January 2022)  

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Factors affecting winter damage and recovery of newly planted Norway spruce seedlings in boreal forests / Jaana Luoranen in Forest ecology and management, vol 503 (January-1 2022)  

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