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The dendrochemical approach holds significant promise for determining the geographical origin of wood as a complementary tool to dendroprovenancing based on tree-ring width. Tracing the origin of wood based on its elemental and isotopic composition is in particular interesting for provenance studies at the regional scale, as dendrochemical signatures are indicative of geological and pedological characteristics. Although, absorption of nutrients and trace elements reflects the composition of soil bioavailable pools, it is also modulated by multiple environmental and tree related factors. We assess the dendrochemical approach in oak wood provenance studies regarding the challenges posed by 1) geochemical variation at a local level, and 2) dendrochemical variation related to oak species, age and social status. A combination of 13 elemental concentrations and 2 isotope - Sr and Nd - ratios was analyzed in oak wood from 12 forests situated in the large Seine river catchment in France. The sampling targeted sites with representative types of geological parent material, where adult trees of two common temperate Quercus species (Quercus petraea and Quercus robur) were selected. The impact of tree characteristics was markedly weaker than that of the site factor and the minimal differences in dendrochemical composition between Quercus petraea and Quercus robur were considered without effect on determination of the geographical origin. Linear discriminant analysis based on Ca-normalized elemental concentrations and Sr and Nd isotope ratios correctly classified the origin of 93 % of the sampled trees. Strontium isotope ratio 87 Sr/ 86 Sr was the strongest provenance indicator capable of determining the origin of 55 % of wood samples on its own. Our system based on elemental and strontium and neodymium isotopic compositions provides robust indicators for wood tracing and might be applied to provenance studies in environment, physiology, history and archeology., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Aims: Afforestation of trace-element contaminated soils, notably with fast growing trees, has been demonstrated to be an attractive option for bioremediation due to the lower costs and dispersion of contaminants than conventional cleanup methods. Mycorrhizal fungi form symbiotic associations with plants, contributing to their tolerance towards toxic elements and actively participating to the biorestoration processes. The aim of this study was to deepen our understanding on the effects of mycorrhizal inoculation on plant development and fungal community at two trace-element contaminated sites (Pierrelaye and Fresnes-sur-Escaut, France) planted with poplar ( Populus trichocarpa x Populus maximowiczii )., Methods: The 2 sites were divided into 4 replicated field blocks with a final plant density of 2200 tree h -1 . Half of the trees were inoculated with a commercial inoculum made of a mix of mycorrhizal species. The sites presented different physico-chemical characteristics (e.g., texture: sandy soil versus silty-loam soil and organic matter: 5.7% versus 3.4% for Pierrelaye and Fresnes-sur-Escaut, respectively) and various trace element contamination levels., Results: After 7 years of plantation, inoculation showed a significant positive effect on poplar biomass production at the two sites. Fungal composition study demonstrated a predominance of the phylum Ascomycota at both sites, with a dominance of Geopora Arenicola and Mortierella elongata , and a higher proportion of ectomycorrhizal and endophytic fungi (with the highest values observed in Fresnes-sur-Escaut: 45% and 28% for ECM and endophytic fungi, respectively), well known for their capacity to have positive effects on plant development in stressful conditions. Furthermore, Pierrelaye site showed higher frequency (%) of mycorrhizal tips for ectomycorrhizal fungi (ECM) and higher intensity (%) of mycorrhizal root cortex colonization for arbuscular mycorrhizal fungi (AMF) than Fresnes-sur-Escaut site, which translates in a higher level of diversity., Conclusions: Finally, this study demonstrated that this biofertilization approach could be recommended as an appropriate phytomanagement strategy, due to its capacity to significantly improve poplar productivity without any perturbations in soil mycobiomes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ciadamidaro, Pfendler, Girardclos, Zappelini, Binet, Bert, Khasa, Blaudez and Chalot.)

Growing lignocellulosic crops on marginal lands could compose a substantial proportion of future energy resources. The potential of poplar was explored, by devising a field trial of two hectares in 2007 in a metal-contaminated site to quantify the genotypic variation in the growth traits of 14 poplar genotypes grown in short-rotation coppice and to assess element transfer and export by individual genotypes. Our data led us to conclusions about the genotypic variations in poplar growth on a moderately contaminated site, with the Vesten genotype being the most productive. This genotype also accumulated the least amounts of trace elements, whereas the Trichobel genotype accumulated up to 170 mg Zn kg -1 DW in the branches, with large variation being exhibited among the genotypes for trace element (TE) accumulation. Soil element depletion occurred for a range of TEs, whereas the soil content of major nutrients and the pH remained unchanged or slightly increased after 10 years of poplar growth. The higher TE content of bark tissues compared with the wood and the higher proportion of bark in branches compared with the wood led us to recommend that only stem wood be harvested, instead of the whole tree, which will enable a reduction in the risks encountered with TE-enriched biomass in the valorization process., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The aim of the present study is to deepen the current understanding of the microbial communities at two poplar phytomanagement sites to reveal the environmental factors that drive the abundance, diversity and composition of microbial communities. A soil analysis revealed that the two soils displayed contrasting physico-chemical characteristics, with significant lower pH and higher Cd, Zn and Mn CaCl2-extractable fractions at Leforest site, compared with Pierrelaye site. The fungal and bacterial community profiles in the poplar roots and soils were assessed through Illumina MiSeq sequencing. Diversity indices and β-diversity measures illustrated that the root microbial communities were well separated from the soil microbial communities at both sites. A detailed study of the fungal composition showed that Ascomycota dominated the overall fungal communities on poplar soil, the root samples at Pierrelaye, and the unplanted soil at the experimental sites. Conversely, Basidiomycota accounted for a much higher percentage of the fungal community in poplar root samples from the Leforest site. The root bacterial communities were dominated by Alphaproteobacteria and Actinobacteria, and the soil samples were dominated by Alphaproteobacteria and Acidobacteria. The occurrence and dominance of the ectomycorrhizal community at Leforest but not at Pierrelaye is the major feature of our data set. Overall, ectomycorrhizal root symbionts appeared to be highly constrained by soil characteristics at the phytomanagement sites. Our data support the view that mycorrhizal inoculation is needed in highly stressed and nutrient-poor environments., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Although current Hg emissions from industrial activities may be accurately monitored, evidence of past releases to the atmosphere must rely on one or more environmental proxies. We used Hg concentrations in tree cores collected from poplars and willows to investigate the historical changes of Hg emissions from a dredged sediment landfill and compared them to a nearby control location. Our results demonstrated the potential value of using dendrochemistry to record historical Hg emissions from past industrial activities., (Copyright © 2016 Elsevier Inc. All rights reserved.)