Articles containing the keyword 'chemical properties'

The investigation concerns with the strength of the eccentric growth accompanying formation of tension wood in silver birch  (Betula pendula Roth.) and downy birch (Betula pubescens Ehrh.), behaviour of wood in wood-working machines and its macroscopic characteristics, its microscopic and sub-microscopic structure, chemical composition, resistance against certain chemicals, physical properties, and the strength characteristics of wood.

The most detrimental properties of tension wood used in wood working industry are high longitudinal shrinkage, warping, twisting and checking. The wooliness of the cut is unwanted, for instance, in plywood and furniture. In pulp industry tension wood is better raw material than normal wood because it yields more and purer cellulose than normal wood. However, it has poorer strength properties.

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• Ollinmaa, E-mail: po@mm.unknown

This study evaluated the transformation of a Pinus tabuliformis Carrière forest into a near-natural forest after 60 years of natural development. The structure and soil characteristics of P. tabuliformis planted forest, the near-natural forest (coniferous-broadleaved P. tabuliformis mixed forest), and secondary forest (Quercus mongolica Fisch. ex Ledeb. forest) were compared. Tree, shrub and herb species diversity of the mixed and Q. mongolica forests was higher than that of the planted P. tabuliformis forest. Examination of soil characteristics revealed that compared to the pure pine forest, nitrogen (N) and phosphorus (P) concentrations of the mixed and Q. mongolica forests increased in the forest floor and soil, but total carbon (C) concentration decreased in the forest floor, countered by increases in the soil. Furthermore, soil cation exchange capacity (CEC) and pH in the P. tabuliformis forest increased when deciduous broadleaved species were present. Total microbial biomass and bacterial biomass in the soils were greatest in the Q. mongolica forest, followed by the mixed, and then the P. tabuliformis forests. However, fungal biomass did not significantly differ among the three forests. Overall, the findings of this study suggest that different forest types can affect soil microbial biomass and community structure. Meanwhile, the natural development is recommended as a potential management alternative to near-natural transformation of a P. tabuliformis planted forest.

• Chen, Department of Plant Biology & Ecology, College of Life Sciences, Nankai University, Weijin Road 94, Tianjin 300071, P.R. China E-mail: guopingchern@mail.nankai.edu.cn
• Shi, Graduate School of Agriculture, Hokkaido University, Sapporo, Hokkaido 060-8689, Japan E-mail: cshi1@for.agr.hokudai.ac.jp
• Cheng, School of Environment and Energy, Shenzhen Graduate School of Peking University, Shenzhen 518055, China E-mail: 1401213932@sz.pku.edu.cn
• Zhao, Baxian Mountain National Nature Reserve, Tianjin 301900, China Received 29 September 2016 Revised E-mail: zhaotiejiann456@sina.com
• Liu, Baxian Mountain National Nature Reserve, Tianjin 301900, China Received 29 September 2016 Revised E-mail: liuguoquan01@163.com
• Shi, Department of Plant Biology & Ecology, College of Life Sciences, Nankai University, Weijin Road 94, Tianjin 300071, P.R. China E-mail: fcshi@nankai.edu.cn