7 research outputs found
Cork oak vulnerability to fire: the role of bark harvesting, tree characteristics and abiotic factors
Forest ecosystems where periodical tree bark harvesting is a major economic activity may be particularly vulnerable to
disturbances such as fire, since debarking usually reduces tree vigour and protection against external agents. In this paper
we asked how cork oak Quercus suber trees respond after wildfires and, in particular, how bark harvesting affects post-fire
tree survival and resprouting. We gathered data from 22 wildfires (4585 trees) that occurred in three southern European
countries (Portugal, Spain and France), covering a wide range of conditions characteristic of Q. suber ecosystems. Post-fire
tree responses (tree mortality, stem mortality and crown resprouting) were examined in relation to management and
ecological factors using generalized linear mixed-effects models. Results showed that bark thickness and bark harvesting are
major factors affecting resistance of Q. suber to fire. Fire vulnerability was higher for trees with thin bark (young or recently
debarked individuals) and decreased with increasing bark thickness until cork was 3–4 cm thick. This bark thickness
corresponds to the moment when exploited trees are debarked again, meaning that exploited trees are vulnerable to fire
during a longer period. Exploited trees were also more likely to be top-killed than unexploited trees, even for the same bark
thickness. Additionally, vulnerability to fire increased with burn severity and with tree diameter, and was higher in trees
burned in early summer or located in drier south-facing aspects. We provided tree response models useful to help
estimating the impact of fire and to support management decisions. The results suggested that an appropriate
management of surface fuels and changes in the bark harvesting regime (e.g. debarking coexisting trees in different years or
increasing the harvesting cycle) would decrease vulnerability to fire and contribute to the conservation of cork oak
ecosystemsinfo:eu-repo/semantics/publishedVersio
Assessing changes in global fire regimes
PAGES, Past Global Changes, is funded by the Swiss Academy of Sciences and the Chinese Academy of Sciences and supported in kind by the University of Bern, Switzerland. Financial support was provided by the U.S. National Science Foundation award numbers 1916565, EAR-2011439, and EAR-2012123. Additional support was provided by the Utah Department of Natural Resources Watershed Restoration Initiative. SSS was supported by Brigham Young University Graduate Studies. MS was supported by National Science Centre, Poland (grant no. 2018/31/B/ST10/02498 and 2021/41/B/ST10/00060). JCA was supported by the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 101026211. PF contributed within the framework of the FCT-funded project no. UIDB/04033/2020. SGAF acknowledges support from Trond Mohn Stiftelse (TMS) and University of Bergen for the startup grant ‘TMS2022STG03’. JMP participation in this research was supported by the Forest Research Centre, a research unit funded by Fundação para a Ciência e a Tecnologia I.P. (FCT), Portugal (UIDB/00239/2020). A.-LD acknowledge PAGES, PICS CNRS 06484 project, CNRS-INSU, Région Nouvelle-Aquitaine, University of Bordeaux DRI and INQUA for workshop support.Background The global human footprint has fundamentally altered wildfire regimes, creating serious consequences for human health, biodiversity, and climate. However, it remains difficult to project how long-term interactions among land use, management, and climate change will affect fire behavior, representing a key knowledge gap for sustainable management. We used expert assessment to combine opinions about past and future fire regimes from 99 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300. Results Respondents indicated some direct human influence on wildfire since at least ~ 12,000 years BP, though natural climate variability remained the dominant driver of fire regime change until around 5,000 years BP, for most study regions. Responses suggested a ten-fold increase in the frequency of fire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in frequency, severity, and size in all biomes except grassland ecosystems. Fire regimes showed different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher warming scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, while recognizing that management options are constrained under higher emission scenarios. Conclusion The influence of humans on wildfire regimes has increased over the last two centuries. The perspective gained from past fires should be considered in land and fire management strategies, but novel fire behavior is likely given the unprecedented human disruption of plant communities, climate, and other factors. Future fire regimes are likely to degrade key ecosystem services, unless climate change is aggressively mitigated. Expert assessment complements empirical data and modeling, providing a broader perspective of fire science to inform decision making and future research priorities.Peer reviewe
data_Ungulates_and_ecosystem_services: Ungulates mediate trade-offs between carbon storage and wildfire hazard in Mediterranean oak woodlands
Data set for the accepted paper in the Journal of Applied Ecolog
Data total of trees and sites parameters
This is an excel file with trees and sites variables collected in 15 studied forests in the North of Tunisia
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Assessing changes in global fire regimes
Acknowledgements: This study emerged during the PAGES-supported Global Paleofire Working Group 2 workshop “Fire history baselines by biome” held in September 2016 at Château de la Tour, Beguey (Bordeaux, France) led by A.-L. D. and Tim Brücher. We thank Virginia Iglesias and Elizabeth Lynch for participating in this study. We thank Isabella Errigo for her assistance in generating Fig. 1a. We dedicate this manuscript to our late colleague Dr. Daniele Colombaroli.Abstract
Background
The global human footprint has fundamentally altered wildfire regimes, creating serious consequences for human health, biodiversity, and climate. However, it remains difficult to project how long-term interactions among land use, management, and climate change will affect fire behavior, representing a key knowledge gap for sustainable management. We used expert assessment to combine opinions about past and future fire regimes from 99 wildfire researchers. We asked for quantitative and qualitative assessments of the frequency, type, and implications of fire regime change from the beginning of the Holocene through the year 2300.
Results
Respondents indicated some direct human influence on wildfire since at least ~ 12,000 years BP, though natural climate variability remained the dominant driver of fire regime change until around 5,000 years BP, for most study regions. Responses suggested a ten-fold increase in the frequency of fire regime change during the last 250 years compared with the rest of the Holocene, corresponding first with the intensification and extensification of land use and later with anthropogenic climate change. Looking to the future, fire regimes were predicted to intensify, with increases in frequency, severity, and size in all biomes except grassland ecosystems. Fire regimes showed different climate sensitivities across biomes, but the likelihood of fire regime change increased with higher warming scenarios for all biomes. Biodiversity, carbon storage, and other ecosystem services were predicted to decrease for most biomes under higher emission scenarios. We present recommendations for adaptation and mitigation under emerging fire regimes, while recognizing that management options are constrained under higher emission scenarios.
Conclusion
The influence of humans on wildfire regimes has increased over the last two centuries. The perspective gained from past fires should be considered in land and fire management strategies, but novel fire behavior is likely given the unprecedented human disruption of plant communities, climate, and other factors. Future fire regimes are likely to degrade key ecosystem services, unless climate change is aggressively mitigated. Expert assessment complements empirical data and modeling, providing a broader perspective of fire science to inform decision making and future research priorities.
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