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Regeneration in European beech forests after drought: the effects of microclimate, deadwood and browsing / Dominik Thom in European Journal of Forest Research, vol 142 n° 2 (April 2023)  

Public [article]  inEuropean Journal of Forest Research > vol 142 n° 2 (April 2023) . - pp 259 - 27 Titre : Regeneration in European beech forests after drought: the effects of microclimate, deadwood and browsing Type de document : Article/Communication Auteurs : Dominik Thom, Auteur ; Christian Ammer, Auteur ; Peter Annighöfer, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : pp 259 - 27 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Allemagne [Termes IGN] bois mort [Termes IGN] Fagus sylvatica [Termes IGN] rayonnement lumineux [Termes IGN] régénération (sylviculture) [Termes IGN] sécheresse [Termes IGN] sous-étage [Termes IGN] température de l'air [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) With progressing climate change, increasing weather extremes will endanger tree regeneration. Canopy openings provide light for tree establishment, but also reduce the microclimatic buffering effect of forests. Thus, disturbances can have both positive and negative impacts on tree regeneration. In 2015, three years before an extreme drought episode hit Central Europe, we established a manipulation experiment with a factorial block design in European beech (Fagus sylvatica L.)-dominated forests. At five sites located in southeastern Germany, we conducted three censuses of tree regeneration after implementing two different canopy disturbances (aggregated and distributed canopy openings), and four deadwood treatments (retaining downed, standing, downed + standing deadwood and removing all deadwood), as well as in one untreated control plot. In addition, we measured understory light levels and recorded local air temperature and humidity over five years. We (i) tested the effects of experimental disturbance and deadwood treatments on regeneration and (ii) identified the drivers of regeneration density as well as seedling species and structural diversity. Regeneration density increased over time. Aggregated canopy openings supported species and structural diversity, but reduced regeneration density. Tree regeneration was positively associated with understory light levels, while maximum vapor pressure deficit influenced tree regeneration negatively. Deadwood and browsing impacts on regeneration varied and were inconclusive. Our study indicates that despite the drought episode regeneration in beech-dominated forests persisted under moderately disturbed canopies. However, the positive effect of increased light availability on tree regeneration might have been offset by harsher microclimate after canopies have been disturbed. Numéro de notice : A2023-197 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s10342-022-01520-1 Date de publication en ligne : 24/11/2022 En ligne : https://doi.org/10.1007/s10342-022-01520-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=103084 [article]

Resource-based growth models reveal opportunities to mitigate climate change effects on beech regeneration by silvicultural measures / Jan F. Wilkens in Forest ecology and management, vol 532 (March-15 2023)  

Public [article]  inForest ecology and management > vol 532 (March-15 2023) . - n° 120815 Titre : Resource-based growth models reveal opportunities to mitigate climate change effects on beech regeneration by silvicultural measures Type de document : Article/Communication Auteurs : Jan F. Wilkens, Auteur ; Robert Schlicht, Auteur ; Sven Wagner, Auteur Année de publication : 2023 Article en page(s) : n° 120815 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Europe (géographie politique) [Termes IGN] Fagus sylvatica [Termes IGN] gestion forestière [Termes IGN] modèle de croissance végétale [Termes IGN] rayonnement solaire [Termes IGN] régénération (sylviculture) [Termes IGN] semis (sylviculture) [Termes IGN] sylviculture [Vedettes matières IGN] Végétation et changement climatique Résumé : (auteur) Successful European beech (Fagus sylvatica L.) regeneration is both of great ecological and economical importance in European forest ecosystems and severely threatened by climate change impacts. To increase our knowledge of beech regeneration dynamics under climate change and the potential for controlling it through forest management, we studied interactive effects of solar radiation (PHAR), water and nutrient availability on the height growth of artificially (AR) and naturally regenerated (NR) beech seedlings. The study was conducted in the framework of experimental canopy gaps, under the influence of the 2018/19 drought and heatwaves. We measured PHAR by means of hemispherical photography, approximated water availability based on the inverse of modeled fine root density distributions of overstorey beech (BGRB) and oak (BGRO) and approximated nutrient availability based on soil fertility (SF), derived from forest site mapping. Results indicate that seedling resource availability and resulting growth responses increase with canopy gap size and vary among locations within the gap. Multiplicative non-linear mixed models suggest that AR and NR relative height growth (RI) was best explained by interactive effects of PHAR, BGRB, BGRO and SF, which reflect complementary resource use patterns of beech seedlings. At optimal resource availability, AR reached a potential RI of 174%, which is about 20% higher compared to NR. While the low light growth responses of AR and NR both reflect saturation at 5 to 15% PHAR, depending on individual size and the availability of the remaining resources, NR showed a higher RI than AR at intermediate and high PHAR levels in cases of limited BGR and SF. In contrast to AR, NR growth was affected to a lesser extent by SF and BGRB and not significantly affected by BGRO. These results suggest that overstorey oaks have a lower effect on water availability of beech seedlings than overstorey beeches. Additionally, NR showed higher tolerance to water and nutrient limitation than AR, probably due to better root system development. In conclusion, site-specific potential for mitigating the effects of climate change on beech regeneration through forest management lies in the adaptation of silvicultural systems, i.e., the creation of canopy gaps larger than 200 m2, thus significantly exceeding the average gap size of the natural disturbance regime, and the choice of the regeneration method. Numéro de notice : A2023-164 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1016/j.foreco.2023.120815 Date de publication en ligne : 26/01/2023 En ligne : https://doi.org/10.1016/j.foreco.2023.120815 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102869 [article]

Can mixed forests sequester more CO2 than pure forests in future climate scenarios? A case study of Pinus sylvestris combinations in Spain / Diego Rodríguez de Prado in European Journal of Forest Research, vol 142 n° 1 (February 2023)  

Public [article]  inEuropean Journal of Forest Research > vol 142 n° 1 (February 2023) . - pp 91 - 105 Titre : Can mixed forests sequester more CO2 than pure forests in future climate scenarios? A case study of Pinus sylvestris combinations in Spain Type de document : Article/Communication Auteurs : Diego Rodríguez de Prado, Auteur ; Aitor Vazquez Veloso, Auteur ; Yun Fan Quian, Auteur ; et al., Auteur Année de publication : 2023 Article en page(s) : pp 91 - 105 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Espagne [Termes IGN] Fagus sylvatica [Termes IGN] gestion forestière [Termes IGN] inventaire forestier étranger (données) [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 climatique Résumé : (auteur) Adapting forests to climate change is a critical issue for forest management. It requires an understanding of climate effects on forest systems and the ability to forecast how these effects may change over time. We used Spanish Second National Forest Inventory data and the SIMANFOR platform to simulate the evolution of CO2 stock (CO2 Mg · ha−1) and accumulation rates (CO2 Mg · ha−1 · year−1) for the 2000–2100 period in pure and mixed stands managed under different Shared Socioeconomic Pathways (SSPs) in Spain. We hypothesized that (1) the more optimistic climate scenarios (SSP1 >  > SSP5) would have higher CO2 stock and accumulation rates; (2) mixed stands would have higher CO2 stock and accumulation rates than pure stands; and (3) the behavior of both variables would vary based on forest composition (conifer–conifer vs. conifer–broadleaf). We focused on Pinus sylvestris L., and its main mixtures with Pinus nigra, Pinus pinaster, Fagus sylvatica and Quercus pyrenaica. The SSP scenarios had correlating CO2 stock values in which SSP1 > SSP2 > SSP3 > SSP5, ranging from the most optimistic (SSP1) to the most pessimistic (SSP5). Though pure stands had higher CO2 stock at the beginning, differences with regard to mixed stands were drastically reduced at the end of the simulation period. We also found an increase in the aboveground CO2 proportion compared to belowground in conifer–broadleaf mixtures, while the opposite trend occurred in conifer–conifer mixtures. Overall CO2 accumulation rates decreased significantly from the beginning to the end of the simulation period, but our results indicated that this decline would be less drastic in mixed stands than in pure ones. At the end of the simulation period, CO2 accumulation rates were higher in mixed stands than in pure stands for all mixtures, fractions (aboveground and belowground) and SSPs. Knowing the evolution of mixed forests in different climate scenarios is relevant for developing useful silvicultural guidelines in the Mediterranean region and optimizing forestry adaptation strategies. Better understanding can also inform the design of management measures for transitioning from pure stands to more resource efficient, resistant and resilient mixed stands, in efforts to reduce forest vulnerability in the face of climate change. This work highlights the importance and benefits of mixed stands in terms of CO2 accumulation, stand productivity and species diversity. Numéro de notice : A2023-138 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s10342-022-01507-y Date de publication en ligne : 16/10/2022 En ligne : https://doi.org/10.1007/s10342-022-01507-y Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102691 [article]

Species-specific deadwood density, its controlling factors and its role in the estimation of deadwood C stock of a Virgin European Beech-Silver Fir Mixed Forest in the Southern Carpathians / Ion Catalin Petritan in SSRN [preprint electronic journal], vol 2023 ([01/02/2023])  

Public [article]  inSSRN [preprint electronic journal] > vol 2023 [01/02/2023] Titre : Species-specific deadwood density, its controlling factors and its role in the estimation of deadwood C stock of a Virgin European Beech-Silver Fir Mixed Forest in the Southern Carpathians Type de document : Article/Communication Auteurs : Ion Catalin Petritan, Auteur Année de publication : 2023 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] Abies alba [Termes IGN] bois mort [Termes IGN] Carpates [Termes IGN] décomposition [Termes IGN] densité du bois [Termes IGN] estimation statistique [Termes IGN] Fagus sylvatica [Termes IGN] peuplement mélangé [Termes IGN] puits de carbone [Vedettes matières IGN] Ecologie forestière Résumé : (auteur) Deadwood is a fundamental structural and functional component of forests, with a crucial role in supporting the forest biodiversity and nutrient and carbon cycling. Precise deadwood density estimates are necessary to evaluate the biomass and carbon stocked in this component. For a better understanding of the deadwood dynamics in natural forests, given its higher abundance, it is important to achieve deeper knowledge about its decay rate and how it is influenced by environmental factors. In this study, we estimated dry deadwood density for two different tree species, silver fir (Abies alba) and European beech (Fagus sylvatica) and for three snags and five logs decomposition classes (class 1 representing snag/log deadwood at early stages of decomposition and class 3/5 representing snags or logs, respectively, at its most advanced state of decomposition) in a virgin mixed beech-fir forest in the Southern Carpathians. The goal of this study was to assess how deadwood density is influenced by different abiotic (moisture, elevation, slope, aspect) and wood-related factors (rottenness, position of the sampling along the deadwood piece, the contact with the soil).For snags, the mean dry density showed a reduced variability within decomposition classes (484-326 kg.m-3 for beech and 374-319 kg.m-3 for fir), compared to the logs (486-139 kg.m-3 for beech and 359-161 kg.m-3 for fir). While the mass moisture varied slowly in the first three decay classes (around 60-80%), it increased sharply in the last two decay classes of logs (> 140% in the fourth classes and > 350% in the last one). The rottenness increased with the decay degree in a similar way for both species. The contact of logs with the soil influenced positively the moisture of the log, but the position of the sampling along the piece did not play any significant role in the variability of density. The density estimates per decay classes were used to compare the amount of carbon (C) sequestered as deadwood for each species. The mean biomass of C as deadwood at Sinca virgin forest varied greatly among the 21 plots from 0.36 to 41.16 MgC ha-1, with a mean value of 15.96 ± 2.36 (±SE) MgC ha-1.Our study suggests that volume-based calculations might yield biased quantitative estimates of C stored as deadwood unless a local estimate of dead wood density corrected per species and decomposition class is applied. Moreover, using an averaged value of dry density instead of dry density value for each decay class may result in an overestimation of 22% on the estimation of C stock sequestered as deadwood. Thus, our study may also help planning future inventories of C stocks in other virgin forests and for other species, (e.g., make emphasis in estimating densities in all decay classes). Furthermore, it could serve as a methodological basis for more specific research designed to uncover the potential influence of different forest management practices on dry deadwood density. Numéro de notice : A2023-085 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.2139/ssrn.4350235 En ligne : https://dx.doi.org/10.2139/ssrn.4350235 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102857 [article]

Assessment of camera focal length influence on canopy reconstruction quality / Martin Denter in ISPRS Open Journal of Photogrammetry and Remote Sensing, vol 6 (December 2022)  

Public [article]  inISPRS Open Journal of Photogrammetry and Remote Sensing > vol 6 (December 2022) . - n° 100025 Titre : Assessment of camera focal length influence on canopy reconstruction quality Type de document : Article/Communication Auteurs : Martin Denter, Auteur ; Julian Frey, Auteur ; Teja Kattenborn, Auteur ; et al., Auteur Année de publication : 2022 Article en page(s) : n° 100025 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie [Termes IGN] Abies alba [Termes IGN] Acer pseudoplatanus [Termes IGN] Allemagne [Termes IGN] canopée [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] Fagus sylvatica [Termes IGN] image captée par drone [Termes IGN] Larix decidua [Termes IGN] longueur focale [Termes IGN] modèle numérique de surface de la canopée [Termes IGN] parcelle forestière [Termes IGN] Picea abies [Termes IGN] reconstruction d'image [Termes IGN] semis de points [Termes IGN] structure-from-motion Résumé : (auteur) Unoccupied aerial vehicles (UAV) with RGB-cameras are affordable and versatile devices for the generation of a series of remote sensing products that can be used for forest inventory tasks, such as creating high-resolution orthomosaics and canopy height models. The latter may serve purposes including tree species identification, forest damage assessments, canopy height or timber stock assessments. Besides flight and image acquisition parameters such as image overlap, flight height, and weather conditions, the focal length, which determines the opening angle of the camera lens, is a parameter that influences the reconstruction quality. Despite its importance, the effect of focal length on the quality of 3D reconstructions of forests has received little attention in the literature. Shorter focal lengths result in more accurate distance estimates in the nadir direction since small angular errors lead to large positional errors in narrow opening angles. In this study, 3D reconstructions of four UAV-acquisitions with different focal lengths (21, 35, 50, and 85 mm) on a 1 ha mature mixed forest plot were compared to reference point clouds derived from high quality Terrestrial Laser Scans. Shorter focal lengths (21 and 35 mm) led to a higher agreement with the TLS scans and thus better reconstruction quality, while at 50 mm, quality losses were observed, and at 85 mm, the quality was considerably worse. F1-scores calculated from a voxel representation of the point clouds amounted to 0.254 with 35 mm and 0.201 with 85 mm. The precision with 21 mm focal length was 0.466 and 0.302 with 85 mm. We thus recommend a focal length no longer than 35 mm during UAV Structure from Motion (SfM) data acquisition for forest management practices. Numéro de notice : A2022-870 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1016/j.ophoto.2022.100025 Date de publication en ligne : 09/11/2022 En ligne : https://doi.org/10.1016/j.ophoto.2022.100025 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=102164 [article]

Climate and ungulate browsing impair regeneration dynamics in spruce-fir-beech forests in the French Alps / Mithila Unkule in Annals of Forest Science, vol 79 n° 1 (2022)  

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Climate envelope analyses suggests significant rearrangements in the distribution ranges of Central European tree species / Gàbor Illés in Annals of Forest Science, vol 79 n° 1 (2022)  

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Development and long-term dynamics of old-growth beech-fir forests in the Pyrenees: Evidence from dendroecology and dynamic vegetation modelling / Dario Martín-Benito in Forest ecology and management, vol 524 (November-15 2022)  

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Age-independent diameter increment models for mixed mountain forests / Albert Ciceu in European Journal of Forest Research, vol 141 n° 5 (October 2022)  

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Detecting overmature forests with airborne laser scanning (ALS) / Marc Fuhr in Remote sensing in ecology and conservation, vol 8 n° 5 (October 2022)  

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Regional climate moderately influences species-mixing effect on tree growth-climate relationships and drought resistance for beech and pine across Europe / Géraud de Streel in Forest ecology and management, vol 520 (September-15 2022)  

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Tracing drought effects from the tree to the stand growth in temperate and Mediterranean forests: insights and consequences for forest ecology and management / Hans Pretzsch in European Journal of Forest Research, vol 141 n° 4 (August 2022)  

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Funding for planting missing species financially supports the conversion from pure even-aged to uneven-aged mixed forests and climate change mitigation / Joerg Roessinger in European Journal of Forest Research, vol 141 n° 3 (June 2022)  

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Unveiling the complex canopy spatial structure of a Mediterranean old-growth beech (Fagus sylvatica L.) forest from UAV observations / Francesco Solano in Ecological indicators, vol 138 (May 2022)  

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Coupling fossil records and traditional discrimination metrics to test how genetic information improves species distribution models of the European beech Fagus sylvatica / Pedro Poli in European Journal of Forest Research, vol 141 n° 2 (April 2022)  

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