Anatomical, chemical, physical and mechanical properties of E. urophylla× grandis and E. globulus at different ages and heights in Yunnan of China

Abstract

In order to make full use of Eucalyptus resources in Yunnan and to realize the oriented cultivation of Eucalyptus plantations and high-value utilization of Eucalyptus for wood composites, this paper analyzed the change pattern of basic wood properties and characteristics including the wood anatomical features, chemical components, physical and mechanical properties, as well as X-ray diffraction of 6–9 years old E. urophylla×grandis 3229 and E. globulus. The results showed that the cellulose content, crystallinity and hot water extractives of Eucalyptus decreased with wood age, while the lignin and hemicellulose content showed the opposite trend; pH value was positively correlated with wood height and negatively correlated with wood age. The basic density of E. urophylla×grandis and E. globules was 0.46 ~ 0.54 g/cm3, belonging to medium-low density wood. The dimensional stability and bengding strength of E. globulus were higher than those of E. urophylla×grandis; the compressive strength of E. urophylla×grandis was grade 5 (95.45 ~ 113.54 MPa) and its hardness was grade 2–3(The end hardness of 9 year reaches 5357.97 MPa.). The study showed that E. urophylla×grandis over 7 to 8 years and E. globulus over 6 year had diameters and mechanical properties that meeting the requirement of Chinese industrial timber standards.