Anabel Aparecida de Mello, Leif Nutto, Karla Simone Weber, Carlos Eduardo Sanquetta, Jorge Luis Monteiro de Matos, Gero Becker. (2012). Individual biomass and carbon equations for Mimosa scabrella Benth. (bracatinga) in southern Brazil. Silva Fennica vol. 46 no. 3 article id 44. https://doi.org/10.14214/sf.44

Keywords: carbon offsets; forest inventory; firewood; modeling; tree compartments

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Mimosa scabrella Benth. is an important native species of southern Brazil widely used for energy and promising for reforestation carbon offsets. Quantification of biomass and carbon stock is valuable for both purposes. From a forest inventory conducted in southern Brazil, data of M. scabrella were analyzed. Thirty sample trees were felled, excavated and weighed in the field and brought to laboratory for biomass and carbon determination. The total aboveground biomass represented 85% of the tree biomass, while roots corresponded to 15%. Correlation matrix of diameter at 1.3 m height (D), tree height (H) versus total and compartment biomass (P) indicated strong association between tree dimensions and biomasses. Five regression models were tested and equations were fitted to data of five biomass compartments and total tree biomass. The best fitting model for total biomass was P = –0.49361 + 0.034865 x D²H whereas for the partial biomass of the compartments was lnP = β₀ + β₁ x ln(D) + β₂ lnH. Carbon concentration was statistically significantly different in foliage than in other compartments. Three approaches of calculating carbon stocks were evaluated and compared to actual data: 1) Estimated total biomass x weighted mean carbon concentration; 2) Estimated partial (compartment) biomass x compartment average carbon concentration; and 3) Carbon regression equations. No statistical difference was detected among them. It was concluded that biomass equations fitted in this study were accurate and useful for fuelwood and carbon estimations.

de Mello, Federal University of Sergipe, Brazil E-mail: aadm@nn.br
Nutto, Federal University of Paraná, Brazil E-mail: lnutto.ufpr@gmail.com
Weber, Federal University of Paraná E-mail: ksw@nn.br
Sanquetta, Carlos Eduardo Sanquetta E-mail: ces@nn.br
Monteiro de Matos, Jorge Luis Monteiro de Matos E-mail: jlmdm@nn.br
Becker, University of Freiburg, Institute of Forest Utilization and Work Science, Germany E-mail: gb@nn.de

article id 187, category Research article

Tobias Biechele, Leif Nutto, Gero Becker. (2009). Growth strain in Eucalyptus nitens at different stages of development. Silva Fennica vol. 43 no. 4 article id 187. https://doi.org/10.14214/sf.187

Keywords: growth stress; growth strain; Eucalyptus nitens; stages of development; sawnwood

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Eucalypts are renowned for their high growth stress levels. These stresses cause splitting, warping and dimensional instability when cutting, processing and drying the wood. In Chile, large Eucalyptus nitens plantations can be found, which, due to these problems, are scarcely utilised for solid wood products (veneer, sawn wood). This study aims to determine the factors influencing growth stress at different stages of tree’s development, and to identify whether the factors influencing growth stress change over time. In five stands of different ages, growth strain, as an indicator of growth stress, was measured at different tree heights with the single hole drilling method. The tree variables DBH, tree height, slenderness (height/diameter ratio) and crown parameters also were measured. A correlation analysis of tree variables and growth strains was undertaken. The results obtained indicate a high variability in growth strain values. It was concluded that growth strain is not correlated with a single growth parameter, but with a combination of factors that variously influence it at different ages and tree heights.

Biechele, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany E-mail: tobias.biechele@fobawi.uni-freiburg.de
Nutto, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany E-mail: ln@nn.de
Becker, University of Freiburg, Institute of Forest Utilisation and Work Science, Werthmannstr. 6, DE-79085 Freiburg, Germany E-mail: gb@nn.de

Category : Research note

article id 61, category Research note

Janine Schweier, Gero Becker. (2012). Harvesting of short rotation coppice – harvesting trials with a cut and storage system in Germany. Silva Fennica vol. 46 no. 2 article id 61. https://doi.org/10.14214/sf.61

Keywords: productivity; harvest operations; marginal sites; SRC; Stemster MK III

Abstract | View details | Full text in PDF | Author Info

Short rotation coppice (SRC) harvesting techniques are available in Germany, but broad experience and knowledge about machine performance and the related effective costs of harvesting operations are still missing. This information is crucial, as harvesting costs strongly influence the economic performance of the overall supply chain. Therefore, it was the aim of this study to collect and analyze productivity data of different harvesting systems for SRC. The combined cut and chip system on the one hand and the cut and storage system on the other hand were studied by literature review. Several studies analyze the combined cut and chip systems and the reported machine productivities showed great variations. The average was 30 green tons per scheduled machine hour (gt smh^–1). Few studies are analysing the cut and storage system. They report that machines still are under development and that further research is needed. Therefore, time studies of harvesting operations using the cut and storage system were carried out. Five trials were performed with the harvesting machine “Stemster MK III” developed by Nordic Biomass. The share of productive working time was 85% and the average productivity was 21 gt smh^–1. These results were compared with values from the literature. Resulting harvesting costs were calculated per oven dry ton (euros odt^–1). The advantages and disadvantages of both harvesting systems are highlighted.

Schweier, Albert-Ludwigs-University Freiburg, Institute of Forest Utilisation and Work Science, Freiburg, Germany E-mail: janine.schweier@fobawi.uni-freiburg.de
Becker, Albert-Ludwigs-University Freiburg, Institute of Forest Utilisation and Work Science, Freiburg, Germany E-mail: gb@nn.de

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