Within-tree and radial variations of wood properties in naturally regenerated trees of Betula platyphylla grown in Nikko, Japan

ABSTRACT

Wood properties were investigated for nine naturally regenerated trees of Betula platyphylla Sukaczev var. japonica (Miq.) H. Hara in Nikko, Japan to effectively utilise the wood resources. The following properties were determined: stress-wave velocity of stems in radial direction, cell length, basic density, shrinkage, dynamic Young’s modulus, modulus of elasticity, modulus of rupture, absorbed energy in impact bending, and compressive strength parallel to grain. All examined wood properties increased from pith to bark. The boundary between core and outer wood determined by a 1.0% annual increment of cell lengths was well matched with that determined by radial variations of wood properties. Significant differences were found between the core and outer wood in several wood properties. Based on the results, it is concluded that when the wood of B. platyphylla is utilised as an industrial raw material, the presence of core and outer wood should be considered.

KEYWORDS:

• Betula platyphylla
• stress-wave velocity
• core and outer wood
• wood properties

Acknowledgements

The authors would like to thank Mr. Yusuke Takahashi, Utsunomiya University, for his great assistance in the experiments.

Disclosure statement

No potential conflict of interest was reported by the author(s).