Estimating canopy height and its changes at meter resolution from satellite imagery remains a challenging computer vision task with critical environmental applications. However, the lack of open-access datasets at this resolution hinders the reproducibility and evaluation of models. We introduce Open-Canopy, the first open-access, country-scale benchmark for very high-resolution (1.5 m) canopy height estimation, covering over 87,000 km(2) across France with 1.5 m panchromatic resolution satellite imagery and aerial LiDAR data. Additionally, we present Open-Canopy-Delta, a benchmark for canopy height reduction detection between images from different years at tree level-a difficult task for current computer vision models. We evaluate state-of-the-art architectures on these benchmarks, highlighting significant challenges and opportunities for improvement. Our datasets and code are publicly available at https://github.com/fajwel/Open-Canopy.

Association of organic matter (OM) with mineral phases have been identified as one important process to explain organic carbon sequestration in soil. Associations include cationic bridging between OM and mineral surfaces, OM adsorption on mineral surface, and OM co-precipitation with minerals. Some recent studies underlined the crucial role of poorly crystalline aluminium (Al) and iron (Fe) oxides to sequestrate organic carbon. These findings have been mostly observed so far at a global or continental scale. Moreover, the links between soil mineralogy and geochemistry and carbon are still unclear, given the time span needed to unveil them.The aim of the study is to verify if relationships between geochemical parameters and soil carbon content are still noticeable at the scale of the French European territory, in temperate forests covering a wide range of soil types. Taking advantage of a double inventory of soil organic carbon at a 15-year interval, we further aim to assess if a relationship exists between soil geochemical parameters and C dynamics over a decade. In this forest monitoring network of 102 sites across mainland France (RENECOFOR) three soil depths were analysed at each campaign: 0–10, 10–20, 20–40 cm. The particulate organic carbon (POC) fraction proportion of the 0–10 cm soil depth was known for 53 sites for the second campaign. The mineral-associated organic carbon (MAOC) content could be therefore inferred.The soil carbon content was linked to the oxalate-extractable Al and Fe (Alox and Feox) at each of the three depths. The relation with the MAOC content of the 53 sites subset was also highly positively correlated. The cation content (exchangeable calcium and magnesium, Caex and Mgex) showed a positive effect on carbon content for a subset of the sites. These had a higher pH and were mainly located on alkaline parent rocks. However, the stock change was mainly unaffected by neither minerals nor cation content, or by other soil characteristics.

The delivery of soil-based ecosystem services (ES) is of increasing importance for spatial planners. Soils are complex and heterogeneous systems, therefore synthesizing pedological expertise into decision support maps presents ongoing challenges. Our approach considers the properties of the entire pedon to assess the contribution of different soil types and land covers to ES delivery at the territorial scale. This study adapts the Destisol decision support tool, initially developed for urban soils and therefore adapted to a high variety of pedons influenced by human activities, to a rural setting containing croplands, grasslands and forests. 86 soil profiles from the study territory are grouped into eight dominant soil types. Nine ES are evaluated based on the horizon-specific physico-chemical properties of each soil type, and mapped following a territorial 1/ 50,000 pedological map. The study territory has a high potential for ES provision with a mean score of 2 +/- 0.2 (min: 1.7, max: 2.7) on a scale of 0 to 3. Soil type is shown to have a significant impact on ES supply under the same land cover. Eutric Cambisols rank highly for provisioning and regulating services, Gleysols rank poorly for water quality but highly for global climate mitigation, and shallow rocky soils rank poorly for most services except water infiltration. Mapping results and soil-type specific ES scores can be used as spatial planning tools to quantify the impact of a given scenario of land cover change on ES scores, and thereby contribute to efforts towards no net loss of soil functionality.

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As a part of the biogeochemical cycle, nutrient translocation plays an important role in enhancing the capacity of perennial plants to grow in nutrient-poor soils. Although leaf translocation has been extensively studied, nutrient translocation between wood rings has received considerably less attention, primarily because of methodological constraints. This study aimed to (i) evaluate the effects of different drying techniques on Ca, K, and Mn concentrations, (ii) calibrate a semi-quantitative method for obtaining ring-to-ring nutrient concentrations along wood cores, and (iii) develop a complete calculation chain for nutrient translocation. Three pairs of cores per tree were extracted from nine oaks, and three drying methods—103 °C, 65 °C, and freeze-drying—were applied to each core pair. For each core pair, the first core was analyzed using ITRAX. The second core was analyzed using ICP-OES following the mineralization of a 20 mg wood sample. Ca, K, and Mn concentrations and wood density were not affected by the drying methods (p>0.05 for Ca, K, and Mn). After upscaling at the stand level, the total translocation was 10.8 ± 5.5 kg ha−1, 14.8 ± 11.4 kg ha−1, and 2.6 ± 0.9 kg ha−1 for Ca, K, and Mn, respectively, after 45 growing years. The total Ca, K, and Mn translocation showed a strong tree effect, partly explained by tree diameter. The study findings suggest that similar measurements can be performed on all wood cores sampled in previous studies and stored after air-drying. These results provide a reference for future analyses of Ca, K, and Mn translocations in different species from wide geographic areas.

The growing demand for renewable materials and energy leads to intensified forest management practices. Therefore, combining high forest productivity and soil carbon storage capacity with lower quantities of organic matter (OM) left on the ground to decompose represents a major challenge. Although microbial communities drive processes responsible for organic carbon stabilization in soil, we have limited knowledge of how the inputs of superficial OM affect the richness and composition of soil microbial communities. This study determined the impacts of OM removal on soil bacteria and fungi at six sites across French temperate forests using high-throughput amplicon sequencing. After three years of OM manipulation, we measured an alteration of the bacterial copiotrophic and fungal saprotrophic abundance and richness. Furthermore, aboveground OM removal reshaped microbial communities toward bacterial oligotrophic and fungal ectomycorrhizal-dominated populations, which are less efficient for OM decomposition. Finally, we proposed that understanding the response of soil microbial communities to variations in OM inputs should help anticipate future functional changes in forest ecosystems submitted to the intensification of silvicultural practices.

Soils constitute a carbon reservoir that can help to mitigate climate change, or conversely accelerate greenhouse gas emissions if not managed properly. Soils are heterogenous and dynamic systems, which physico-chemical properties impact their current soil organic carbon (SOC) stocks and their capacity to store more carbon. Land-use planning aiming to preserve and increase SOC stocks should therefore be aware of the spatial repartition of various soil types and of the SOC dynamics therein. This project aims to map the effect of soil typology on the spatial and vertical repartition of soil carbon stocks, additional storage potential and storage dynamics at a regional scale to improve guidance of SOC storage strategies. The study site is a 320 km2 temperate rural region in NE France. Eight dominant soil types are defined, notably Calcaric cambisols in the agricultural valleys, deep silty and acidic soils in the forested plateaus, shallow rocky calcaric soils on the hillslopes, and deep clay-rich hydromorphic soils in the alluvial valleys. Based on logarithmic fits of soil carbon data extracted from 197 full-depth soil profiles, mean soil organic carbon stocks are obtained as a function of depth for each represented soil type and land cover. The additional storage potential corresponds to the difference between the current stock and the maximum stock, as estimated by the fit of the upper 25% of the soil carbon content data. Finally, a depth-dependent SOC dynamic model using multilayer soil modules is used to simulate SOC stock evolution. Results are mapped by combining the spatial information given by a pedological map and a map of land covers. Median soil carbon stocks over the full soil profile range from 78 to 333 tC ha-1, of which 59 to 148 tC ha-1 are in the topsoil (0-30 cm). The lower stocks are found in the shallow, rocky cultivated soils, and the highest stocks in the gleysols under grasslands. The additional storage potential varies from 19 tC ha-1 for shallow, rocky forest soils to 197 tC ha-1 for cultivated gleysols. SOC build-up is heterogenous and depends on the mean residence time of carbon in the represented soil types. Maps of carbon stocks show the areas to preserve to avoid C losses, and maps of additional storage capacity for different time horizons show areas in which to implement carbon storage practices. Going forward, the association of carbon stock mapping and modelling should allow us to estimate at which depths and over which timescales.

Context Bioenergy from wood can contribute to reach the goals of energy-transition policies. Use of wood as fuel should focus on low-quality wood, e.g. by-products from timber production, which production and supply is related to various management decisions. Reaching the policy objectives efficiently remains an issue. Aims The aims are (1) to develop a modelling approach that links local management decisions with indicators of the whole wood fuel production and supply chain and (2) to test the model in a case study. The study should further provide first insights on how indicators of energy, nutrient and worktime efficiency vary according to wood fuel chain characteristics and the related management decisions. Methods The model depicts the flow of wood (biomass, nutrients, moisture content, heating value) from the forest stand to the heating plant for each silvicultural intervention simulated with a growth and yield model. It further quantifies the energy and worktime spent on different wood fuel chain tasks (e.g. felling, forwarding) set by the user. We defined four scenarios according to the scale of energy production (large vs. small) and the demand for wood fuel (high vs. moderate). Results The case study revealed that the model outputs were plausible. Energy efficiency largely varied depending on the type of silvicultural intervention. Large-scale production associated with high demand was most favourable for energy and worktime efficiencies. In contrast, nutrient efficiency was best for small-scale production associated with moderate demand. Conclusions Local management decisions all along the wood fuel chain highly influenced efficiency indicators, and thus its relevance for energy-transition policies. Our model may contribute to strategic decision making in different forestry and energy production contexts.

As highlighted by recent regulations in Europe and worldwide, the multifunctionality of soils and their capacity to deliver services to societies are of increasing importance to land planners and decision makers. Soils provide multiple ecosystem services (ES) including food production, biomass-energy and contribution to climate change regulation through carbon storage. These services need to be estimated and visualised at relevant scales in order to improve their consideration in land planning decisions.This project aims to map interdependent bundles of soil ecosystem services at a regional scale so that the effect of land planning decisions on ES delivery can be apprehended by stakeholders. The study site is a 320 km2 rural region in Meuse/Haute Marne, France, composed of 56% cropland, 30% forest and 14% grassland. The pedological properties are provided by 85 soil profiles, grouped into 8 dominant soil types, and a 1/50,000 pedological map. Soil typology is dominated by Calcaric cambisols in the agricultural valleys, but features also deep silty and acidic soils in the forested plateaus, shallow rocky calcaric soils on the hillslopes, and deep clay-rich hydromorphic soils in the alluvial valleys.Using an expert-based decision support model (Destisol1), soil functions and ecosystem services were scored for all spatial units defined by soil type, slope category and land cover. Functions are calculated based on the soil bio-physico-chemical properties across the whole depth of the pedons. Scores, ranging from 0 to 3, are based on expert-based rules defining threshold values for all soil indicators. Correction factors are applied to the ecosystem service scores to account for the effect of land cover. Finally, correlated bundles of ES across all spatial units are obtained by principal component analysis.Our results synthetise the effect of soil type on ecosystem services provision, and display the spatial synergies and tradeoffs through three maps of ES bundles. The first ES bundle map compiles the provisioning services (food production, provision of construction wood, provision of biomass energy), which depend dominantly on land use. The second map shows the hydrological regulating services (water quality, erosion mitigation and flooding mitigation), which depend on slope, land use and soil hydromorphy. The third map shows the climate and biological regulating services (contribution to climate change regulation through carbon storage, local cooling effect, biodiversity), which depend on land use, soil depth, rock fragment content and organic matter content. Going forward, maps of ES bundles could be generated for different land planning scenarios to assess the ensuing losses and gains of ES, and promote a more holistic consideration of soil ES by stakeholders.Reference: 1. Blanchart, A. et al. Towards an operational methodology to optimize ecosystem services provided by urban soils. Landsc. Urban Plan. 176, 1–9 (2018).

Background: Higher exportation of harvest residues from forests due to increased demand for woody biomass, has reportedly diminished soil mineral resources and may lead to degraded tree nutrition as well as growth. However, as nutrients become less available in the soil, the remobilization of nutrients in biomass tissues (plant internal cycling) helps sustain tree nutrition. Our study aims to quantify the impact of Removing Harvest Residues and Litter (RHRL) during five years on tree growth, wood density, and stem wood nutrient concentrations in young beech and oak forest stands. Result: Our study found that, RHRL significantly decreased tree growth ring width by 14%, and wood density by 3%, in beech trees, in near bark rings. RHRL also significantly reduced nutrient concentration in near bark and near pith areas of both studied species. Mg, Na and S were found lower by 44%, 76%, and 56%, respectively, in near bark area of beech trees. In near bark area of oak trees, K, Ca, Mg, Na, S, and Fe were lower by 20%, 25%, 41%, 48%, 41%, and 16%, respectively. K and Mg concentrations decreased more strongly in near pith area compared to near bark area suggesting internal translocation of these two elements. Conclusion: In beech trees, wood density proved to be an important factor while quantifying the effect of removing harvest residuals on tree growth and biomass. Soil nutrient loss intensified the remobilization of nutrients con-tained in older tree rings (close to the pith) towards newly formed rings (close to bark). In our study, in beech trees, K was found to be the most recycled major nutrient. These results demonstrate the potential of such analysis for providing valuable insight into the effect of RHRL in premature stands on the physiological adaptive strategies of trees and an indication of soil fertility status.