The Wood Fiber Characteristics Of Eucalyptus Dunnii Provenances

In this thesis, basic density, wood fiber configuration, organization proportion were investigated in a20-year-old Eucalyptus dunnii plantation, with10provenances planted in Shatang Forest Farm of Guangxi. Relationships among these three wood properties and variation of each tested property among provenances were analysised. In sequence, means of principal component analysis were undertaken to evaluated comprehensively the10E. dunnii provenances and superior provenances were selected. The results are as follows:(1) Among the provenances of E. dunnii, there were significant differences in tree height and DHB(diameter at breast height over bark). A good effect could be obtained by selection among the provenances.(2) Variations of fiber morphology:●Average fiber length of plantation-grown E. dunnii wood ranged from855.52to1011.12μm, which is suitable for paper industry. The fiber length increased gradually from pith towards outside. Variation of the fiber length within provenance showed great differences, which could benefit the improvement of the fibre length.●Average fiber width of plantation-grown E. dunnii wood was in a range of17.94～23.3μm. Its radial variation showed gradual decrease from pith to bark.●Average ratio of fiber length to widthwas influenced by the fiber length. The ratio had an increasing trend from pith to bark and average ratio for each provenance was between46.09and54.60, which is suitable for paper industry..●Average double radial wall thickness of E. dunnii ranged from7.01μm to14.63μm. Its radial variation from pith towards outside was decreased.●Average ratio of fiber diameter to width was in the range of0.45～0.61, and its radial variation showed a decreasing trend from pith to bark.●Ratio of double wall thickness to diameter was greater than1for A, B, D and E provenances, while the ratio of others were less than1.Radial variation of the ratio showed a trend that heartwood<middle wood<sapwood.(3) Three superior provenances (A, K and D provenances) were screened out by using principal component analysis.(4) Wood tissue proportion:●The vessel-elements proportion increased or decreased from the pith to the middle in radial direction, while the proportion from mid-part to the bark showed opposite trend.●The radial variation of fiber proportion was conform to that of the vessel-elements proportion, but the radial variation of fiber proportion was samller.●The radial variation of ray proportion had an increasing or decreasing trend from pith to the mid-part, but showed an opposite change from mid-part towards outside.●The radial variation of parenchyma proportion was discordant.(5) Correlation analysis:there was a positive relationship between fiber length and vessel-elements proportion, but correlations of fiber length with basic density, fiber proportion, ray proportion and parenchyma proportion were negative. There was a positive correlation between fiber width and vessel-elements proportion, but the associations between fiber width and other three tissue proportions (including fiber proportion, ray proportion and parenchyma proportion) were negative. Double wall thickness had a positive correlation with basic density.