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Forecasting the development of boreal paludified forests in response to climate change: a case study using Ontario ecosite classification

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Forest Ecosystems 2015年第1期2卷 45-55页

作者： Benoit Lafleur Nicole J Fenton yves bergeron Institut de recherche sur les forêts Université du Québec en Abitibi-Témiscamingue 445 boul. de l’Université Rouyn-Noranda QC J9X 5E4 Canada Centre d’étude de la forêt Université du Québec à Montréal 141 Avenue du Président-Kennedy Montréal QC H2X 1Y4 Canada

Background：Successional paludification,a dynamic process that leads to the formation of peatlands,is influenced by climatic factors and site features such as surficial deposits and soil *** boreal regions,projected climate change and corresponding modifications in natural fire regimes are expected to influence the paludification process and forest *** objective of this study was to forecast the development of boreal paludified forests in northeastern North America in relation to climate change and modifications in the natural fire regime for the period 2011–***：A paludification index was built using static（*** deposits and soil texture）and dynamic（*** regime and soil organic layer thickness）stand scale factors available from forest *** index considered the effects of three temperature increase scenarios（i.e.＋1°C,＋3°C and＋6°C）and progressively decreasing fire cycle（from 300 years for 2011–2041,to 200 years for 2071–2100）on peat accumulation rate and soil organic layer（SOL）thickness at the stand level,and paludification at the landscape ***：Our index show that in the context where in the absence of fire the landscape continues to paludify,the negative effect of climate change on peat accumulation resulted in little modification to SOL thickness at the stand level,and no change in the paludification level of the study area between 2011 and ***,including decreasing fire cycle to the index resulted in declines in paludified ***,the index predicts a slight to moderate decrease in the area covered by paludified forests in 2100,with slower rates of ***：Slower paludification rates imply greater forest productivity and a greater potential for forest harvest,but also a gradual loss of open paludified stands,which could impact the carbon balance in paludified ***,as the thick Sphagnum layer typical of paludified forests may protect soil organic layer from dr

关键词： Boreal forest Canada Carbon sequestration Paludification Peat forests Forest harvest

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Stand history is more important than climate in controlling red maple (Acer rubrum L.) growth at its northern distribution limit in western Quebec, Canada

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Journal of Plant Ecology 2015年第4期8卷 368-379页

作者： Yun Zhang yves bergeron Xiu-Hai Zhao Igor Drobyshev Institut de recherche sur les forêts Universitédu Québec en Abitibi-Témiscamingue(UQAT)445 boul.de l’UniversitéRouyn-NorandaQuébec J9X 5E4Canada Key Laboratory for Forest Resources&Ecosystem Processes of Beijing Beijing Forestry UniversityBeijing 100083P.R.China Swedish University of Agricultural Sciences Southern Swedish Forest Research CentrePO Box 49Alnarp SE-23053Sweden Present address:National Plateau Wetlands Research Center Southwest Forestry UniversityKunming 650224P.R.China.

Aims We examined growth of red maple(Acer rubrum l.)to evaluate environmental controls of its northern distributional limit in Eastern North america and its potential response to future climate *** We collected growth data from nine sites located along a 300-km transect(47-49°N),which included frontier population of red maple and covered three bioclimatic domains in western *** ana-lyzed three growth variables:growth rates during the first 30 years of maple lifespan,cumulative basal area increment(ba I)over the most recent decade(2000-2009)and annual growth rate over the whole tree lifespan ranging from 58 to 112 *** also examined growth sensitivity to climate by using response function *** Findingsthree different proxies of maple absolute growth(initial growth rate,ba I during 2000-09 and mean diameter growth rate)indicated a better growth with an increase in *** speculate that stand history effectively overrode the direct effects of colder climate on maple growth along the s-N *** of maple in the southern sites likely occurred in canopy gaps,whereas in the north it was contingent upon large disturbances such as stand-replacing fires,which apparently provided more favorable light environment for maple growth than canopy *** annual growth variability,which reflects effects of annual weather on growth and is largely independent from the absolute growth rate,was significantly affected by monthly climate,suggesting a positive effect of higher summer temperature in the northern part of the transect(48-49°N)and a negative effect of summer drought in the south(47-48°N).In the future,the natural and human disturbance regimes will be dominant controls of the actual biomass productivity of red maple at the northern limit of its present distribution *** effects of climate on maple growth would likely be less important in this context,and will likely entail negative effect of increased summer drought

关键词： biomass productivity climate change dendrochronology ecotone hardwoods species migration

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Holocene variations of wildfire occurrence as a guide for sustainable management of the northeastern Canadian boreal forest

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Forest Ecosystems 2015年第3期2卷 190-196页

作者： Ahmed El-Guellab Hugo Asselin Sylvie Gauthier yves bergeron Adam A.Ali NSERC/UQAT/UQàM Industrial Chair in Sustainable Forest Management Université du Québec en Abitibi-Témiscamingue Natural Resources Canada Canadian Forest Service – Laurentian Forestry Centre Centre for Bio-Archeology and Ecology (UMR5059 CNRS) Université Montpellier 2

Background: Cumulative impacts of wildfires and forest harvesting can cause shifts from closed-crown forest to open woodland in boreal ecosystems. To lower the probability of occurrence of such catastrophic regime shifts,forest logging must decrease when fire frequency increases, so that the combined disturbance rate does not exceed the Holocene maximum. Knowing how climate warming will affect fire regimes is thus crucial to sustainably manage the forest. This study aimed to provide a guide to determine sustainable forest harvesting levels, by reconstructing the Holocene fire history at the northern limit of commercial forestry in Quebec using charcoal particles preserved in lake ***: Sediment cores were sampled from four lakes located close to the northern limit of commercial forestry in Quebec. The cores were sliced into consecutive 0.5 cm thick subsamples from which 1 cm3 was extracted to count and measure charcoal particles larger than 150 microns. Age-depth models were obtained for each core based on accelerator mass spectroscopy(AMS) radiocarbon dates. Holocene fire histories were reconstructed by combining charcoal counts and age-depth models to obtain charcoal accumulation rates and, after statistical treatment,long-term trends in fire occurrence(expressed as number of fires per 1000 years).Results: Fire occurrence varied between the four studied sites, but fires generally occurred more often during warm and dry periods of the Holocene, especially during the Holocene Thermal Maximum(7000–3500 cal. BP), when fire occurrence was twice as high as at ***: The current fire regime in the study area is still within the natural range of variability observed over the Holocene. However, climatic conditions comparable to the Holocene Thermal Maximum could be reached within the next few decades, thus substantially reducing the amount of wood available to the forest industry.

关键词： Fire occurrence Holocene Boreal forest Northern li

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Have some landscapes in the eastern Canadian boreal forest moved beyond their natural range of variability?

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Forest Ecosystems 2018年第4期5卷 412-428页

作者： Pierre Grondin Sylvie Gauthier Veronique Poirier Patrice Tardif Yan Boucher yves bergeron Direction de la Recherche Forestiere Ministere des Foretsde la Faune et des Pares (MFFP)2700rue EinsteinQuebecQC GIP 3W8Canada Ressources Naturelles Canada/Natural Resources Canada Service Canadien des forets/Canadian Forest ServiceCentre de foresterie des Laurentides/Laurentian Forestry Center1055 rue du P.E.P.SQuebecQC G1V 4C7 Canada Institut de Recherche sur les Forets Universite du Quebec en Abitibi-Temiscamingue445boul.de I'UniversiteRouyn-NorandaQC J9X 5E4Canada Centre d'etude de la Foret Universite du QuebecMontreal CP 8888succ AMontrealQC H3C 3P8Canada

Background: In the contxt of ecosystem management, the present study aims to compare the natural and the present-day forested landscapes of a large territory in Quebec(Canada). Using contemporary and long-term fire cycles, each natural forst landscape is defined according to the variability of its structure and composition, and compared to the present-day landscape. This analysis was conducted to address the question of whether human activities have moved these ecosystems outside the range of natural landscape ***: The study encompassed a forested area of 175 000 km2 divided into 14 landscapes. Using a framework that integrates fire cycles, age structure and forest dynamics, we characterized the forest composition and age structures that resulted from three historical fire cycles(110,140, and 180 years) representative of the boreal forest of eastern Canada. The modeled natural landscapes were compared with present-day landscapes in regard to the proportion of old-growth forests(landscape level) and the proportion of late-successional forest stands(landscape level and potential vegetation type).Results: Four landscapes(39%) remain within their natural range of variability. In contrast, nine landscapes(54%)show a large gap between natural and present-day landscapes. These nine are located in the southern portion of the study area, and are mainly associated with Abies-Betula vegetation where human activities have contributed to a strong increase in the proportion of Populus tremuloides stands(early-successional stages) and a decrease of oldgrowth forest stands(more than 100 years old). A single landscape(7%), substantially changed from its potential natural state, is a candidate for adaptive-based ***: Comparison of corresponding natural(reference conditions) and present-day landscapes showed that ten landscapes reflecting an important shift in forest composition and age structure could be considered beyond the range of their natural v

关键词： Ecosystem management Reference conditions Natural variability Resilience Fire cycle Age structure Forest dynamics Potential vegetation type Landscape ecology Theoretical natural landscape Present-day landscape

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Ecosystem management in paludified boreal forests:enhancing wood production,biodiversity,and carbon sequestration at the landscape level

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Forest Ecosystems 2018年第4期5卷 376-389页

作者： Benoit Lafleur Nicole J.Fenton Martin Simard Alain Leduc David Paré Osvaldo Valeria yves bergeron NSERC-UQAT-UQAM Industrial Chair in Sustainable Forest Management and Institut de recherche sur les forêts Université du Québec en Abitibi-Témiscamingue445boul.de I'UniversiteRouyn-NorandaQC J9X 5E4Canada Department of Geography Laval UniversityQuebecQC GIV 0A6Canada Centre d'etude de la foret Universite du Quebec a Montreal141 Avenue du President-KennedyMontrealQC H2X IY4Canada Ressources Naturelles Canada Service canadien des forets Centre de foresterie des Laurentides1055du P.E P S.P.O.13ox 3800QuebecQC GIV 4C7Canada

Canada’s boreal forest represents an important contributor of the world’s wood supply industry. However,maintaining or increasing productivity of the boreal forest may be challenging in areas dominated by forested peatlands. Moreover, sustainable management of these forests must also consider other important aspects of the forest ecosystem such as biodiversity and carbon sequestration. To address these concerns, ecosystem-based management has been implemented in some Canadian jurisdictions, such as in regions where a large portion of the boreal forest is dominated by forested peatlands. The objectives of this paper are(1) to summarize our current understanding of how natural disturbances influence stand dynamics and biodiversity in forested peatlands, and(2) to review the main differences between natural and managed forest stands with respect to soil properties, stand productivity, understory plant communities. We also discuss how even-age management regime succeeds or fails to preserve old forests and how this loss affects both forest structure and habitat diversity at the landscape *** conclude by showing how, in boreal forested peatlands, forest management could contribute to carbon sequestration and mitigate projected climate change.

关键词： Clearcutting Fire Forest dynamics Partial cutting Soil properties Stand productivity Understory plant

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The importance of increasing primary vaccinations against COVID-19 in Europe

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Infectious Disease Modelling 2024年第1期9卷 1-9页

作者： Pierre-yves Boelle Eugenio Valdano Sorbonne Universite INSERMInstitut Pierre Louis d’Epidemiologie et de Sante PubliqueF75012ParisFrance

In the European Union,mass vaccination against COVID-19 staved off the strict restrictions that had characterized early epidemic ***,vaccination campaigns are focusing on booster doses,and primary vaccinations have all but ***,52 million European adults are *** investigated if reaching the still unvaccinated population in future vaccination campaigns would substantially decrease the current burden of COVID-19,which is *** focused on vaccination homophily,whereby those who are unvaccinated are mostly in contact with other unvaccinated,making COVID-19 circulation *** quantified vaccination homophily and estimated its impact on COVID-19 *** used an online survey of 1,055,286 people from 22 European countries during early *** computed vaccination homophily as the association between reported vaccination status and perceived vaccination uptake among one's own social contacts,using a case-referent design and a hierarchical logistic *** used this information in an analysis of the COVID-19 reproduction ratio to determine the impact of vaccine homophily in *** homophily was present and strong everywhere:the average odds ratio of being vaccinated for a 10-percentage-point increase in coverage among contacts was 1.66(95%CI=(1.60,1.72)).Homophily was positively associated with the strictness of COVID-19-related restrictions in 2020(Pearson=0.49,P=.03).In the countries studied,12%-to-18%of the reproduction ratio would be attributable to vaccine *** vaccination homophily may curb the reproduction ratio substantially even to the point of preventing recurrent epidemic *** addition to boosting those already vaccinated,increasing primary vaccination should remain a high priority in future vaccination campaigns,to reduce vaccination homophily:this combined strategy may decrease COVID-19 burden.

关键词： COVID-19 Vaccination campaign Reproduction ratio Vaccination homophily Survey Europe

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卫星遥感研究火灾对大气成分和短波辐射的影响:多个例研究

卫星遥感研究火灾对大气成分和短波辐射的影响:多个例研究

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第35届中国气象学会年会

作者：符玉云李锐黄建国 yves bergeron 傅云飞王雨中国科学技术大学中国科学院华南植物园 Université du Québec en Abitibi-Témiscamingue (UQAT)

本研究利用Aqua卫星的MODIS,AIRS,CERES传感器、Aura卫星的OMI传感器对火灾释放的气溶胶、大气痕量气体、及相应大气顶短波辐射等物理量的遥感反演结果研究了火灾对大气成分和短波辐射的影响。所选择的火灾个例及其相应的主要燃料类型为... 详细信息

本研究利用Aqua卫星的MODIS,AIRS,CERES传感器、Aura卫星的OMI传感器对火灾释放的气溶胶、大气痕量气体、及相应大气顶短波辐射等物理量的遥感反演结果研究了火灾对大气成分和短波辐射的影响。所选择的火灾个例及其相应的主要燃料类型为:中国东北地区(NEC)农作物火灾个例、西伯利亚的混合型森林火灾、加利福利亚的针叶林火灾。中国东北农田火灾个例中,以火辐射功率(FRP)计算的气溶胶排放系数(Ce)为20.51±2.55gMJ。该排放率仅约为西伯利亚混合型森林火灾(40.01±9.21 g MJ)和加利福利亚针叶林火灾(45.23±8.81 g MJ)的一半。中国东北农田火灾的CO释放率也仅为23.94±11.83 g MJ,约为西伯利亚混合型森林火灾的1/3和加利福利亚针叶林火灾的1/2。然而,中国东北农田火灾的NOx释放率(2.76±0.25 g MJ)却是另外两个火灾的约3倍。因此,中国东北农田火灾的烟幕中,NOx对其他污染物包括气溶胶、甲醛(HCHO)、CO的比例远高于其他火灾。尽管不同火灾释放的大气污染物的速率、相对成分有很大差异,但是他们在大气顶所产生的短波直接辐射强迫系数却非常接近,为20.09±0.892.93±1.01 Wm per AOD.该研究揭示了大尺度空间下不同火灾对区域大气成分的影响,所发现的差异很有可能与火灾的燃料类型、火灾的燃烧状态(闷烧、明火)等有关。该研究结果对利用多源卫星观测结果估算气溶胶等大气污染物的释放率以及以及他们所造成的大气短波辐射强迫有应用价值。

关键词：火灾卫星遥感气溶胶 NOx CO 短波辐射强迫

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Multifunctional properties of a polar spin chain compound[N(C_(3)H_(7))_(4)][Cu(C_(8)H_(4)NO_(4))]·H_(2)O exhibiting both one-dimensional magnetism and nonlinear optical activity

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Chinese Chemical Letters 2024年第2期35卷 622-625页

作者： Ang Li Yanhong Wang Haotian Tian Alimujiang Yalikun yves Journaux Min Luo Hongcheng Lu Key Laboratory of Material Chemistry for Energy Conversion and Storage School of Chemistry and Chemical EngineeringHubei Key Laboratory of Bioinorganic Chemistry & Materia MedicaHuazhong University of Science and TechnologyWuhan 430074China Key Laboratory of optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 35002China Institut Parisien de Chimie Moléculaire IPCMSorbonne UniversitéCNRSParis F-75252France

Functional materials with multiple properties are urgent to be explored to reach high requirements for applications *** this work,a new multifunctional one-dimensional(1D)chain compound[N(C_(3)H_(7))_(4)][Cu(ohpma)]·H_(2)O 1(ohpma=deprotonated N-(2-hydoxyphenyl)oxamic acid)exhibiting both 1D antiferromagnetic and nonlinear optical properties,which are both originated from the same polar[Cu(C_(8)H_(4)NO_(4))]magnetic units,has been successfully synthesized by evaporation at room ***-polydentate nature of the(ohpma)3−ligand with constrained tridentate and bidentate coordination sites conducts Cu^(2+)ions coordinating in different geometries and forms 1D chains along the c axis,which are further separated by the[N(C_(3)H_(7))_(4)]+*** the 1D magnetic chains further exhibit noncentrosymmetric polar *** optical study shows polar compound 1 exhibits a discernible second-harmonic generation(SHG)efficiency and the calculation of the partial density of states indicates that the SHG efficiency of 1 is mainly originated from the polar[Cu(C_(8)H_(4)NO_(4))]magnetic ***,magnetic susceptibility shows a broad maximum around 70 K with strong intrachain interaction of J/k B=−113.0 K but no long-range order is observed down to 2 K,suggesting that 1 shows a good 1D *** good 1D magnetism and SHG activity suggest that 1 could be as a potential multifunctional material,particularly.

关键词： Multifunctional properties Magnetic property Nonlinear optical property Evaporation One-dimensional chain

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利用新型微波植被指数遥感森林蒸散

利用新型微波植被指数遥感森林蒸散

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第35届中国气象学会年会

作者：王怿璞李锐闵启龙张雷明于贵瑞黄建国 yves bergeron 加拿大魁北克大学美国纽约州立大学大气研究中心中国科学技术大学地球与空间科学学院中国科学院华南植物园中国科学院地理科学与资源研究所

地表蒸散发是陆地水能循环最重要的环节。卫星遥感是获取长时间、大尺度下非均匀植被下垫面蒸散所不可替代的重要方法。大多数卫星遥感蒸发的算法基于光学植被指数(如NDVI),但它时间分辨率较低、在植被茂密的区域易饱和、受云影响大、... 详细信息

地表蒸散发是陆地水能循环最重要的环节。卫星遥感是获取长时间、大尺度下非均匀植被下垫面蒸散所不可替代的重要方法。大多数卫星遥感蒸发的算法基于光学植被指数(如NDVI),但它时间分辨率较低、在植被茂密的区域易饱和、受云影响大、无法在夜晚使用。最近发展的新型微波比辐射率差分植被指数(EDVI)主要反映植被含水量信息,具有穿云能力强、信号不易饱和、能全天候使用等优点,能一定程度上客服光学植被指数的缺陷。本

关键词：遥感微波植被指数蒸散发日变化

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France-China‘Brotherhood'in My Eyes

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China News Release 2024年第2期 14-17页

作者： yves Mouillet tbe French Chaunel of CGTN China Media Group

Though thousands of miles apart,the ancient and refined civilization of China has always held a profound fascination for the people of *** back at the history of recent several centuries,from historical texts and landmarks to meetings between heads of state,we can see many precious moments of amicable exchanges between the two countries.

关键词： refined exchanges profound

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