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Current biomass equations for bark mostly provide differing results from 50-150 % for most physical parameters like bark dry-mass, dry and moist volume and dry-, moist- and space density, even when fed with the same initial values. However, an accurate determination of bark biomass is important for statements about nutrient sustainability, nutrient exports by logging and consequently for practical recommendations based on nutrient balancing. To address these issues, the Bavarian State Institute of Forestry conducted a research project to close knowledge gaps on bark biomass data, including thickness, density, volume, and mass of spruce bark. One of the aims was to choose the most suitable bark biomass equation for Bavarian conditions. Therefore, more than 2,750 bark samples were obtained from three spruce stands in an elaborate arrangement of height stages along the course of the stem using 20 mm hollow punches. Each sample was prepared carefully, and physical measurements were conducted by the method of immersion weighing. Available bark biomass equations were compared to Bavarian conditions and a new biomass equation was developed and statistically tested, based on field data of the BarkBiomass-project., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 40-44

Careful operation during fuel production is essential to avoid highshares of mineral soil inwood chips leading to contamination of the biofuels. This can result in elevated gaseous and particulate emissions, corrosion or slag formation during combustion in the biomass boiler. To investigate this effect, stemwood and forest residue wood chip fuels were contaminated with mineral soil at two different ratios. Contamination was done using three typical forest soils from Bavaria (soil A, B and C). Total particulate matter (TPM) emissions increased for wood chips that when contaminated with soil A and C, compared to the reference fuel, but emissions for wood chips contaminated with soil B remained constant. Carbon monoxide (CO) and organic gaseous carbon (OGC) emissions decreased for contaminated wood chips. For NOX emissions, no clear effect was observed. Overall, the contamination of woody biomass had a noticeable effect on pollutant emissions and should be avoided., Proceedings of the 29th European Biomass Conference and Exhibition, 26-29 April 2021, Online, pp. 662-667

International audience; Background: Differences in weight status by socioeconomic position occur during adolescence and is known as weight social gradient (WSG). The PRALIMAP (Promotion de l'ALIMentation et de l'Activité Physique) trial highlighted that a universal intervention was effective in reducing overweight and obesity prevalence among adolescents. However, its ability to reduce the WSG is unclear. This study aimed to evaluate the impact of the PRALIMAP intervention on the WSG among adolescents. Methods: Data were obtained from 3504 adolescents who participated in the school-based PRALIMAP trial between 2006 and 2009. The PRALIMAP study consisted of three interventional strategies: educational, environmental, screening and care. Weight status was assessed by body mass index (BMI) z-score and overweight and obesity prevalence. The "indice de position sociale des élèves" was used to measure adolescents' socioeconomic status. Linear regression and hierarchical models were used to assess the WSG and its evolution, respectively. Results: Among all adolescents (14-18 years old), significant WSG was identified at baseline: BMI z-score (β = -0.06; p

Due to careless operation during fuel production, considerable shares of mineral soil might be added to wood chips and wood pellets leading to contamination of the biofuels. This can result in high gaseous and particle emissions, corrosion or slag formation during combustion. To investigate this effect, four pellet fuels were produced at TFZ using coniferous wood of Norwegian spruce, i. e. a pure sample as reference and three pellets that were contaminated with different mineral soils (2 w-%). The contaminated pellets had significantly higher ash contents (2.47 to 2.63 w-%, d.b.) compared to the reference fuel (0.83 w-%, d.b.). The reference sample fulfilled the specifications for A2 according to DIN EN ISO 17225-2, while the contaminated pellets only met the I3 quality criteria. A visual differentiation between contaminated and uncontaminated fuels was not possible. The pellets were combusted in a pellet boiler with a nominal heat output of 15 kW. During combustion of the contaminated pellets, the boiler shut down because of to severe slag and ash formation after 118, 120 and 278 minutes of full load operation. Particle emissions and NOX decreased for the soil contaminated pellets compared to the reference fuel while SOX increased. Carbon monoxide was on a very low level for all fuel assortments. A final interpretation of the correlation between soil contamination of wood pellets and their respective emission behaviour is not possible yet as analysis of chemical element concentration is still ongoing. Overall, the contamination of woody biomass had a noticeable effect on emissions and on the continuous, undisturbed operation of the pellet boiler and should be avoided., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 673-680

Sufficient wood chip fuel quality is important for failure-free combustion and less emissions. Unfortunately, mineral soil-contamination can be a serious issue as it can take place during logging or chipping process. Currently, there is no reliable quality management system for chemical wood chip quality established yet. During a previous study, so called "biomass fuel indexes for the contamination with mineral soil" (BFICS) have been developed, utilizing the ratio of Fe/Mn and Al/200. To get a rather quick impression of chemical element contents, an innovative portable EDXRF analyzer should be applied into wood chip supply chain, when quality issues could be concerned. The EDXRF device was calibrated with pulverized wood chip calibration standards (n = 30) of different tree species, in particular spruce and pine, analyzed by ICP-AES. Linear correlations between EDXRF and ICP-AES are quite tight (R > 0.98) and all elements show a sufficient limit of detection. Samples with particle sizes > 0.5 mm have a significant influence on EDXRF measurement reliability. Especially Al and Si are overestimated and show high standard deviations. Concentrations of pulverized (particle sizes < 0.5 mm) wood chips and pellets analyzed by EDXRF coincide well with ICP-AES results. Therefore, contaminated wood chips or pellets with 2 or 10 w-% mineral soil can easily be identified by EDXRF as well as clean material., Proceedings of the 27th European Biomass Conference and Exhibition, 27-30 May 2019, Lisbon, Portugal, pp. 617-623