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Articles by Paul Wallden

Category : Article

article id 7291, category Article
Paul Wallden. (1934). Tutkimuksia koivupuun anatoomisen rakenteen ja teknillisten ominaisuuksien keskinäisestä riippuvuudesta solumittauksien perusteella. Acta Forestalia Fennica vol. 40 no. 14 article id 7291. https://doi.org/10.14214/aff.7291
English title: Studies on relationship between anatomical structure and technical properties of birch wood.
Original keywords: koivu; puu; taivutuslujuus; Betula pubescens; putkilo
English keywords: wood; downy birch; bending strength; tracheid; libriform cell
Abstract | View details | Full text in PDF | Author Info

Birch wood is used widely in wooden structures where mechanical strength is needed. The aim of the research was to study the influence of the relative share of mechanically weak tracheids, and length of the wood fibers on specific gravity and bending strength of downy birch (Betula pubescens Ehrh.) wood. According to the results, the strength of wood is strongly dependent on the relative share of tracheids, and length of the libriform cells. The strength of the wood increases when the share of tracheids decreases and the length of libriform cells increases. The specific gravity can be used as an indication of the strength of wood, especially if it is possible to analyze the structure of the wood.

The PDF includes a summary in German.

  • Wallden, E-mail: pw@mm.unknown (email)
article id 7276, category Article
Paul Walldén. (1933). Eräs puun laadun tunnus. Acta Forestalia Fennica vol. 39 no. 5 article id 7276. https://doi.org/10.14214/aff.7276
English title: Bending strength of birch wood.
Original keywords: koivu; Betula sp.; taivutuslujuus; ominaispaino
English keywords: the specific gravity of cell wall substance
Abstract | View details | Full text in PDF | Author Info

According to earlier studies, the weight of the wood may be a useful quality when aim is to create such wooden structures where small weight is combined with maximum mechanical strength. Of the northern tree species, Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst.) and birch (Betula sp.), birch has the highest bending strength. The main focus of this study was to find out if there is correlation between the specific gravity of cell wall substance and bending strength of the birch wood, and if the specific gravity of cell wall substance could be used as indication of the quality of the wood.

Dominant trees from 55 years old birch (Betula sp.) stand was selected for bending tests. The bending strength did not vary in birch as much as in many other tree species. The highest bending strength was achieved near the specific gravity class s=0,65, and it can be concluded that when the specific gravity falls below S=0,57, the wood’s technical quality is not sufficient. The article includes a literature review on the subject.

The PDF includes a summary in German
  • Walldén, E-mail: pw@mm.unknown (email)

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