Relations between various extracted basic densities and wood chemical components in Eucalyptus globulus

Relations between various extracted basic densities and wood chemical components were investigated by their within-tree variations in Eucalyptus globulus for assistance in the prediction of the properties of wood or wood-derived products. Extraneous compounds affect the relations between various basic densities and wood chemical components such as holocellulose and the lignin syringyl/guaiacyl ratio. We also discuss the relation of various densities, the molar composition of neutral sugars constituting hemicellulose, and fiber morphology.     

Influence of non-genetic factors on yield of monoterpenes in leaf oils of Eucalyptus camaldulensis

Sources of variation in yields (as a fraction of leaf weight) of 1,8-cineole, -pinene, -pinene and limonene in the leaf oils of young Petford Eucalyptus camaldulensis trees were studied. The oil yields of leaves up to 5 months of age were significantly affected by physiological changes associated with leaf maturation. The extent of these changes depends on genotype and on external influences such as soil moisture conditions. Prolonged drought stress reduced oil production in young leaves but did not affect greatly the equilibrium reached between synthesis and removal of oils at leaf maturity. Waterlogging prolonged peak oil production.Trends in oil yields with time differed markedly between individual trees. Although genotypic variation was great, there was detectable variation attributable to site, season and year. A relationship between seasonal patterns and climatic factors could not be established. Part of the observed variation in oil yields with time was attributable to variability in leaf maturity.The relative superiority in oil-yielding capacity of certain individuals in each experiment was maintained throughout, despite substantial variation from non-genetic sources. This consistency in ranking is of advantage to tree breeders wishing to make selections amongst plantations of differing age, on different sites and at different times of the year. However, even with careful sampling controls, absolute values will vary substantially and progeny testing will be necessary to further assess the potential of the initial selections.     

Performance of height-classified Eucalyptus camaldulensis seedlings after one year in the field

Eucalyptus camaldulensis seedlings of 16–25, 26–35, 36–45 and 46–55cm height classes were used to examine the effect of planting stock quality on field performance. Survival, height and diameter (10cm above ground) were assessed 6 and 12 months after planting out. Significant height differences (P 0.05) existed between the 16–25 and 46–55cm height classes at 6 months age. There were no significant (P 0.05) differences in all these parameters at 12 months after planting out throughout the four height classes. It is concluded that the height classification approach for E. camaldulensis seedlings has very little value if the seedlings are in the 16–55cm height range. Until other nursery stock grading approaches are studied, 16–25cm seedling height class is as effective as the taller ones and would therefore be more economical for dry zone afforestation in Malawi.     

Rapid assessment of wood chemical properties and pulp yield of Eucalyptus camaldulensis in Thailand tree plantations by near infrared spectroscopy for improving wood selection for high quality pulp

Near-infrared (NIR) spectroscopy has been demonstrated as a means for rapid nondestructive determination of the chemical composition and final pulp yield of Eucalyptus camaldulensis in Thailand tree plantations. Multiple linear regression (MLR) analysis and partial least squares (PLS) analysis were introduced to develop statistical models in terms of calibration equations for total pulp yield, screened pulp yield, and contents of -cellulose, pentosans, and lignin in wood. In MLR analysis, a reasonably good calibration equation was found only for pentosans (standard error of prediction (SEP): 0.98%). The PLS analysis improved the accuracy of prediction for every criterion variable, especially for pentosans (SEP: 0.91%) and lignin (SEP: 0.52%). Also, in the case of screened pulp yield, we were able to use such a statistical result as an indicator of the characteristics of the pulp and paper. Thus, NIR spectroscopy could be satisfactorily used as an effective assessment technique for Eucalyptus camaldulensis plantation trees.     

Geographic variation and provenance selection for bamboo wood properties in Bambusa chungii

Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences between fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude (from high to low in elevation). The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis. Foundation project: This research was funded by both of the International Tropical Timber Organization (ITTO), grant No. PD10/00. REV. 2 (I,F), and the National ‘Tenth Five-year’ Key Program of China, grant No. 2004BA506B0103.     

Effect of thinning and fertilizer on the cellulose crystallite width of Eucalyptus globulus

An analysis of cellulose crystallite width, microfibril angle and wood density after the time of thinning (at 8 years) in straight vertical trees was undertaken in a 13-year-old E. globulus trial designed to assess the effect of thinning on tension wood formation. The most important effect was on cellulose crystallite width, which increased with thinning intensity and this was mitigated where fertilizer was applied at the time of thinning. Given the relationship between high crystallite width and tension wood occurrence the results demonstrate that heavy thinning of E. globulus at this age can contribute to tension wood formation. However, tension wood production may be significantly reduced where fertilizer is applied. This is possibly because increased diameter growth as a response to fertilizer application stabilises the stems and this is the mechanism by which trees cope with internal stresses that are generated from wind in destabilsed stands following thinning. In contrast, trees that respond poorly to thinning produce tension wood.     

Effects of radial growth rate on selected indices for juvenile and mature wood of the Japanese larch

To examine the differences between juvenile and mature wood, 12 aged sample trees from two areas of Nagano Prefecture were harvested; and the radial development of tracheid length, the ring density, and the relation of the radial growth rate (observed by ring width) with some selected indices of ring structure were investigated. The results proved that the radial variation of tracheid length with ring number can be described by a logarithmic formula, and both plantations reached the demarcation of juvenile and mature wood at age 18. With the segmented regression method, we also analyzed radial variation of mean density and found that the demarcation of juvenile and mature wood was at age 15 for sample trees from Saku and at age 21 for those from Yabuhara. By using the results of estimates from juvenile and mature wood based on ring density, we found that high growth rates resulted when producing lower-density wood during the juvenile period, but these rates did not occur during the mature period. The basic reason for this phenomenon is the variation in patterns of earlywood and latewood in juvenile and mature wood, respectively. This result advised us that when managing plantations of Japanese larch it is necessary to take different measurements at different growth periods.     

Predicting individual breeding values and making forward selections from open-pollinated progeny test trials for seed orchard establishment of interior Lodgepole Pine (<Emphasis Type="Italic">Pinus contorta</Emphasis> ssp. <Emphasis Type="Italic">latifolia</Emphasis>) in British Columbia

Ten-year height data from three open-pollinated lodgepole pine progeny test trials were analysed in order to select individuals for seed orchard establishment in the low and high elevation seed-planning units (TOLO and TOHI) of the new Thompson Okanagan seed planning-zone in interior British Columbia, Canada. The total test population had about 35,000 individuals from 362 families of 9 provenances and was divided into two portions, each serving as the base population for its appropriate seed-planning unit. For each population, various genetic parameters were estimated and individual breeding values were predicted. Combined-site estimates of individual, family, and within-family heritability ranged from 0.23 to 0.38, 0.77 to 0.84, and 0.17 to 0.29, respectively. Estimated coefficients of type-b genetic correlation were greater than 0.81, indicating little G × E interaction in this region. Provenance effects were large. Larch Hills and Inonoaklin River were the two superior provenances with an expected gain of 13% and 10% in stem volume at rotation age of 60 years in TOLO. Individual breeding values was not uniformly distributed among provenances and the top 100 individuals originated from 20 families in TOLO and 32 families in TOHI. Co-ancestry among these individuals should not be a serious concern in seed orchard establishment as the predicted genetic loss due to excessive inbreeding is only 1.06% in TOLO and 0.6% in TOHI. The status numbers of the two prospective seed orchards are 32 and 44, respectively, and both are well above the required minimum of 10 in British Columbia. Using unrelated clones for seed orchard establishment may result in reduced optimum genetic gain and thus is not a favourable option.