@article{BerendtPegelBlaskoetal.2021, author = {Berendt, Ferr{\´e}ol and Pegel, Erik and Blasko, Lubomir and Cremer, Tobias}, title = {Bark proportion of Scots pine industrial wood}, series = {European Journal of Wood and Wood Products}, volume = {79}, journal = {European Journal of Wood and Wood Products}, number = {3}, publisher = {Springer Nature}, issn = {0018-3768}, doi = {10.1007/s00107-021-01657-7}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-1975}, pages = {749 -- 752}, year = {2021}, abstract = {Bark characteristics are not only used in the forest-wood supply chain, for example to calculate standing volumes, but also to transform wood volumes and masses. In this study, bark thickness, bark volume and bark mass were analyzed on the basis of 150 Scots pine discs, with a mean diameter of 13 cm. The mean double bark thickness was 3.02 mm, the mean bark volume proportion was 5.6\% and mean bark mass proportion was 3.3\%. Bark proportions were significantly affected by the log-specific variables 'diameter over bark', 'proportion of bark damage' and 'double bark thickness'.}, language = {en} } @article{BerendtdeMiguelDiezWalloretal.2021, author = {Berendt, Ferr{\´e}ol and de Miguel-Diez, Felipe and Wallor, Evelyn and Blasko, Lubomir and Cremer, Tobias}, title = {Comparison of different approaches to estimate bark volume of industrial wood at disc and log scale}, series = {Scientific Reports}, volume = {11}, journal = {Scientific Reports}, publisher = {Springer Nature}, issn = {2045-2322}, doi = {10.1038/s41598-021-95188-z}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-1987}, pages = {8}, year = {2021}, abstract = {Within the wood supply chain, the measurement of roundwood plays a key role due to its high economic impact. While wood industry mainly processes the solid wood, the bark mostly remains as an industrial by-product. In Central Europe, it is common that the wood is sold over bark but that the price is calculated on a timber volume under bark. However, logs are often measured as stacks and, thus, the volume includes not only the solid wood content but also the bark portion. Mostly, the deduction factors used to estimate the solid wood content are based on bark thickness. The aim of this study was to compare the estimation of bark volume from scaling formulae with the real bark volume, obtained by xylometric technique. Moreover, the measurements were performed using logs under practice conditions and using discs under laboratory conditions. The mean bark volume was 6.9 dm3 and 26.4 cm3 for the Norway spruce logs and the Scots pine discs respectively. Whereas the results showed good performances regarding the root mean square error, the coefficient of determination (R2) and the mean absolute error for the volume estimation of the total volume of discs and logs (over bark), the performances were much lower for the bark volume estimations only.}, language = {en} } @article{BerendtWolfgrammCremer2021, author = {Berendt, Ferr{\´e}ol and Wolfgramm, Felix and Cremer, Tobias}, title = {Reliability of photo-optical measurements of log stack gross volume}, series = {Silva Fennica}, volume = {55}, journal = {Silva Fennica}, number = {3}, issn = {2242-4075}, doi = {10.14214/sf.10555}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-2003}, pages = {1 -- 13}, year = {2021}, abstract = {In terms of assessing economic impact, one of the most important elements in the wood supply chain is the measurement of round wood. Besides the one-by-one measurement of logs, logs are often measured when stacked at the forest road. The gross stacked volume includes the volume of the wood, bark and airspace and is widely used for industrial wood assortments. The increasing international attention given to photo-optical measurement systems for portable devices is due to their simplicity of use and efficiency. The aim of this study was to compare the gross volumes of hardwood log stacks measured using one widespread photo-optical app with two manual section-wise volume estimations of log stacks based on the German framework agreement for timber trade (RVR). The manual volume estimations were done starting from the left (RVRleft) and right (RVRright) sides of the log stacks. The results showed an average deviation of the photo-optical gross volume estimation in comparison to the manual estimation of -2.09\% (RVRleft) and -3.66\% (RVRright) while the deviation between RVRleft and RVRright was +2.54\%. However, the log stack gross volume had a highly significant effect on the deviation and better accuracy with smaller deviation were reached for larger log stacks. Moreover, results indicated that the gross volume estimations of higher quality log stacks were closer for the three analyzed methods compared to estimations of poor-quality log stacks.}, language = {en} } @article{WilmsDuppelCremeretal.2021, author = {Wilms, Florian and Duppel, Nils and Cremer, Tobias and Berendt, Ferr{\´e}ol}, title = {Bark Thickness and Heights of the Bark Transition Area of Scots Pine}, series = {Forests}, journal = {Forests}, number = {12(10)}, publisher = {MDPI}, issn = {1999-4907}, doi = {10.3390/f12101386}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:eb1-opus-4330}, pages = {1 -- 12}, year = {2021}, abstract = {The estimation of forest biomass is gaining interest not only for calculating harvesting volumes but also for carbon storage estimation. However, bark (and carbon) compounds are not distributed equally along the stem. Particularly when looking at Scots pine, a radical change in the structure of the bark along the stem can be noted. At the bark transition area, the bark changes from thick and rough to thin and smooth. The aim of our study was (1) to analyze the height of the bark transition area where the bark structure changes and (2) to analyze the effect of cardinal direction on the bark thickness. Regression analyses and forward selection were performed including measured tree height, DBH, bark thickness, crown base height and upper and lower heights of the bark transition areas of 375 trees. While the cardinal direction had no effect on bark thickness, DBH was found to have a significant effect on the heights of the bark transition areas, with stand density and tree height having a minor additional effect. These variables can be used to estimate timber volume (without bark) with higher accuracy and to predict the carbon storage potential of forest biomass according to different tree compartments and compounds.}, language = {en} }