| In this paper, Mytilaria laosensis plantation were systematic studied on the wood anatomical structure, chemical properties, physicao—mechanical properties and their variation pattern. The research results were as follows :(1) The average of fiber length, fiber width, fiber cavity diameter, fiber wall thickness, ratio of length to width, ratio of thickness to diameter and ratio of cavity to width were respectively 2014.2μm, 26.19μm, 15.12μm, 11.07μm, 78.68, 0.79, 0.57. From pith to bark, the radial variation patterns of fiber length, fiber width, cavity diameter, wall thickness, ratio of length to width and ratio of wall thickness to diameter were gradually increasing, but the ratio of cavity to width was gradually decreasing; Results of regression analysis between fiber morphological parameters and age shown that all fiber morphological parameters were significantly related with age, except for fiber width, fiber cavity diameter and ratio of cavity to width.(2) The average of vessel element length, vessel width, vessel cavity diameter, vessel wall thickness, ratio of length to width, ratio of thickness to diameter and ratio of cavity to width were respectively 1666.0μm, 53.83μm, 48.40μm,5.44μm, 31.85, 0.12, 0.90. From pith to bark, the radial variation patterns of vessel element length, vessel width, ratio of length to width and ratio of cavity to width were gradually increasing,the radial variation patterns of vessel wall thickness and ratio of thickness to diameter were gradually decreasing, but for vessel cavity diameter there was not significant radial variation patterns. Results of regression analysis between vessel morphological parameters and age shown that all the paramenters were significantly related with age, except for vessel width and vessel cavity diameter. (3) The average proportion of fiber tissues, proportion of vessel tissues, proportion of wood ray tissues and proportion of longitudinal parenchyma were respectively 54.8%, 16.5%, 27.6%, 1.1%. From pith to bark, the radial variation pattern of proportion of fiber tissues was gradually increasing, the proportion of vessel tissues was gradually decreasing, but the variation patterns for the proportion of wood ray tissues and proportion of longitudinal parenchyma were not significant. Results of regression analysis between tissue proportions and age shown that all the proportions were significantly related with age, except for proportion of wood ray.(4) The average of microfibrillar angle was 8.4° and its radial variation was gradually decreasing from pith to bark. Regression results shown that microfibrillar angle was significantly related with age.(5) The boundary between juvenile wood and mature wood was the seven year. Variance analysis shown that the difference of fiber length, vessel element length and microfibrillar angle between juvenile wood and mature wood were significant, but the difference of the rest fiber morphological parameters, the rest vessel morphological parameters and proportion of wood tissues were not significant.(6)The contents of wood extractives (excepting hot-water extractives), chemical component and pH value varied significantly along tree stem, but only the 1%NaOH extractives showed significant difference in different trees. Going upwards from the bottom of the tree stem, contents of shot-water extractives were lower in the middle section and higher at two ends, contents of cold-water extractives, 1%NaOH extractives and lignin tend to decrease, contents of holocellulose, hemicellulose and pH value tend to increase, while the content ofcellulose was higher in the middle section and lower at two ends. (7) Wood density was in middle levels and the anisotropic properties of wood in wetting swelling and drying shrinking were very significant. All mechanical properties arrived at middle or high levels. According the above results, comparing to common broad—leaved tree species, wood of Mytilaria laosensis plantation possessed many excellent characteristice, such as fiber length, big vessel element le...
|
PDF Full Text Request