Daily patterns of stem size variation in irrigated and unirrigated Eucalyptus globulus

High resolution measurements of stem diameter variation provide a means to study short-term dynamics of tree growth and water status. In this 14-month study, daily changes in stem radius of Eucalyptus globulus Labill. seedlings were measured with electronic point dendrometers in a plantation in southern Tasmania, Australia. The daily patterns of stem expansion and shrinkage were classified into three phases: shrinkage; recovery; and increase in diameter from one maximum to the next, or increment. This study showed that rapid onset of even mild drought in irrigated trees caused distinct changes in daily patterns of stem diameter variation, particularly the duration of daily stem increment. The duration of the daily increment phase was directly related to increment magnitude. The dynamics of daily increment were significantly affected by mean minimum temperature, indicating a temperature limitation on metabolic processes underlying diameter growth in these trees. Most likely due to differences in conductance, the duration but not rate of the incremental daily expansion was greater in fast- than in slow-growing trees.     

Effect of Coriolus versicolor on physico-chemical properties of Eucalyptus globulus wood

Summary The purpose of this study was to determine the progressive changes in physical and chemical properties of Eucalyptus globulus wood under the action of a representative white rot fungus, Coriolus versicolor. Observations concerning the nature and relative effects on weight loss, hot water solubility, 1% sodium hydroxide solubility, Klason lignin, holocellulose, intrinsic viscosity and degree of polymerisation of holocellulose, pentosans, methoxyl value, neutral sugar composition and nitrobenzene oxidation products are discussed.The authors thank Dr. P. S. Rehill, the then Officer-in-Charge, Forest Pathology Branch, for valuable suggestions and providing facilities for decay experiments     

Wood anatomy and biometric parameters variation of Eucalyptus globulus clones

Variation in wood anatomy and biometric variables was studied in 14 7-year-old Eucalyptus globulus clones grown in a clonal trial in Arauco, Bio-Bio Region, Chile. Biometric characteristics were measured for each tree and the anatomical variables were measured at three radial positions by image analysis on transverse microsections cut from radial increment cores sampled at breast height. Results showed, that among clones wide ranges of variation were found for vessel frequency, vessel area and vessel coverage. However, narrow ranges of variation were found for fiber wall thickness, fiber diameter and lumen diameter. From pith to bark, mean vessel area and vessel coverage increased gradually, whereas the vessel frequency decreased. The fiber wall thickness did not differ significantly from pith to bark. Mean fiber and lumen diameters showed the same radial pattern, increasing from pith to the midpoint of the radius to reach a plateau close to the bark. Furthermore, important commercial volume gains that can exceed 100% were found. Considering the commercial importance of tree volume, vessel and fiber anatomy in the pulping and papermaking process, it is suggested that the information given in this study may be used as an additional criteria for the selection of E. globulus.     

Assessing genetic variation to improve stem straightness in Eucalyptus globulus

Context

Stem straightness is an important trait for growers and processors of Eucalyptus globulus logs for solid-wood products.

Aims

The aims of the study were to determine the extent of genetic variation in stem deviation from straightness in E. globulus and assess the utility of a six-point subjective scoring method as a selection criterion for stem straightness.

Methods

Two E. globulus progeny trials, grown under solid-wood product regimes, were studied. At age 9 years (post-thinning), stem straightness was measured using both image analysis and a six-point subjective scale. Diameter at breast height (DBH; 1.3 m) was measured at both age 5 (pre-thinning) and age 9 years.

Results

Significant additive genetic variation was observed. Strong, positive and significant additive genetic correlations were observed between the stem straightness assessment methods and between DBH at ages 5 and 9 years. Significant positive genetic correlations were shown between subjectively scored stem straightness and DBH at both ages 5 and 9 years.

Conclusion

The six-point subjective scoring method is a cost-effective selection criterion for stem straightness in E. globulus. The image measurement technique may be applied where objective estimates of stem straightness are required, for training purposes and to verify subjective scores.     

Heartwood and sapwood variation in Eucalyptus globulus Labill. trees at the end of rotation for pulp wood production

The amount of heartwood and sapwood in Eucalyptus globulus Labill. wood was determined in commercial pulpwood plantations at harvest age (12 to 15 years) in four ites in central portugal. twelve trees were sampled in each site at nine stem height levels. Heartwood was present in all the trees up to 82%–87% of the total tree height and amounted to 38%–41% of the total tree volume. The heartwood proportion in the stem cross-section decreased from the base upwards, representing 53.3% and 26.1% of the total area respectively at the base and 55% height level. The sapwood width remained relatively constant along the stem at a mean 38 mm up to the 55% height level. The trees within the site, the height level and their interaction were highly significant sources of variation for heartwood proportion and sapwood width. The heartwood diameter and sapwood width were positively correlated with radial tree growth.     

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.     

Nondestructive sampling of Eucalyptus globulus and E. nitens for wood properties. I. Basic density

A non-destructive sampling strategy for basic density, based on removing 12 mm bark-to-bark cores, was developed in E. globulus and E. nitens. Fifty trees of each species, aged 5 to 9 years, were sampled across a range of sites. Core samples were removed on both a north-south and an east-west axis from 6 fixed heights in the base of the tree (0.5 m, 0.7 m, …, 1.5 m). Whole-tree values were calculated from disc samples removed at eight percentage heights (0, 10, 20, …, 70%) and correlations between the cores and whole-tree values were used to determine the optimal sampling height. Core samples were found to be reliable predictors of whole-tree density, explaining between 84% and 89% of the variation between trees. Core sampling of E. globulus and E. nitens to estimate basic density of whole-trees and stands is feasible; cores from trees at all E. globulus sites gave high correlations with whole-tree values. For E. nitens, site differences were apparent, and it is recommended that a small destructive sampling program should be undertaken prior to commencing a major sampling program. Recommended optimal sampling heights are 1.1 m for E. globulus and 0.7 m for E. nitens. Core orientation was not important and density was not related to tree size. Six whole-tree samples or eight core samples are required for estimating the mean density of a stand at a specific site to an accuracy of ±20 kg m⁻³ with a 95% confidence interval. Received 17 September 1998     

Kinetics of acid-catalysed delignification of Eucalyptus globulus wood by acetic acid

Summary The kinetics of HCl-catalysed delignification of Eucalyptus globulus wood by 70% (w/w) acetic acid solution were satisfactorily explained by a model in which 5% of the lignin fraction could not be eliminated and the remaining 95% was eliminated by a single process which, in view of the activation energy calculated from the data was attributed to the hydrolysis of -aryl ether bonds. The selectivity of the process was effectively independent of HCl concentration and operating temperature for pulp yields >50%. At high temperature (160 °C) and catalyst concentration (0.027 MHCl), lignin condensation and precipitation became significant and the data were better fitted by a model comprising two consecutive processes: lignin solubilization followed by lignin condensation.The authors are grateful to the CICYT for financial support of this work (Project AGF93-0605) and also to the DGICYT for a research grant awarded to J. González     

Nondestructive sampling of Eucalyptus globulus and E. nitens for wood properties; II. Fibre length and coarseness

Within-tree variation in fibre length and coarseness was studied in fifty trees of E. globulus and E. nitens to develop a non-destructive sampling strategy. Trees, aged 5 to 9 years, were sampled across a range of sites in southern Australia. Simulated core samples were removed at six fixed heights easily accessible from the ground (0.5, 0.7, ... 1.5 m) and at eight percentage heights (0, 10, 20, ... 70%). Whole-tree values, calculated from percentage height data, were correlated with the core data to determine the optimal sampling height. Core samples were found to be reliable predictors of whole-tree fibre length, but results were variable for fibre coarseness. Simulated cores taken from the recommended sampling heights explained 87% and 71% of variation in whole-tree fibre length for E. globulus and E. nitens respectively and 54% and 45% of the variation in whole-tree fibre coarseness. Fibre length at all fixed heights showed good correlations with whole-tree values at all sites for E. globulus. For E. nitens the correlations were slightly lower and variable across sites. Results for fibre coarseness varied across sampling heights and sites for both species. The recommended sampling height for fibre length is 1.5 m for both species, whilst for fibre coarseness, the recommended sampling heights are 0.9 and 1.1 m for E. globulus, and 0.9 and 1.3 m for E. nitens. Radial orientation of cores was not important and neither fibre length nor coarseness were related to tree size or basic density. To estimate stand mean fibre length to an accuracy of ±5% would require sampling 9 whole trees or taking cores from 13 trees for E. globulus and 4 whole trees or cores from 8 trees for E. nitens. For estimating stand mean fibre coarseness, 10 whole trees of E. globulus and 7 whole trees are needed for E. nitens. Core sampling for stand mean coarseness would require more trees: 13 to 21 for E. globulus and 11 to 16 trees for E. nitens. Received 17 September 1998     

Potential of laccase for modification of Eucalyptus globulus wood: a XPS study

The influence of a commercial laccase on the grafting of 4-chloro-2-methoxyphenol, a model compound, onto Eucalyptus globulus sapwood was evaluated by X-ray photoelectron spectroscopy. The grafting was carried out on extracted and non-extracted wood samples. The extraction procedure modified the surface composition due to extractives removal but with high data dispersion. The laccase-mediated grafting of the chlorophenol was demonstrated by the decrease in O/C ratio and the presence of Cl in wood surface after the enzymatic wood treatment. Laccase seemed to be adsorbed suggesting a possible competition between adsorption and grafting processes. The extractive compounds have no effect on the enzymatic grafting since similar Cl amount was analyzed in extracted and non-extracted wood. This enzymatic grafting methodology opens up new possibilities for wood surface modification in order to obtain new wood products with sustainable technologies and mild conditions.     

Examination of within-tree variations and the heights representing whole-tree values of derived wood properties for quasi-non-destructive breeding of Eucalyptus camaldulensis and Eucalyptus globulus as quality pulpwood

Within-tree variations of derived wood properties of Runkel ratio, Luces shape factor, slenderness ratio, and solids factor were examined for Eucalyptus camaldulensis and Eucalyptus globulus trees and the tendency difference in the within-tree variations between individuals and between species, in both radial and axial directions by statistical data analysis. These properties are important for quality breeding of pulpwood. In both species, within-tree variations were generally observed as higher values in the upper and outer parts compared with other parts of the trunk for Runkel ratio and Luces shape factor. In E. camaldulensis, within-tree variations were observed as higher values in the upper and outer parts compared with other parts of the trunk for slenderness ratio and solids factor. In E. globulus, within-tree variations were observed as higher values in the outer parts compared with other parts for slenderness ratio and solids factor. However, significant difference of tendency was observed in radial variation between individuals of E. globulus for Runkel ratio and in both radial and axial variations between species for solids factor. Furthermore, within-tree variations of derived wood properties were analyzed to determine a sampling height in the trunk which can be used to represent whole-tree values. Representative heights of derived wood properties from two trees were found to be 2.8m in E. camaldulensis (except for Runkel ratio and Luces shape factor) and 1.8m in E. globules (except for Runkel ratio), regardless of differences in tree height (growth rate) and in tendency of within-tree variation of derived wood properties.     

Foliar nutrient retranslocation in Eucalyptus globulus

We measured patterns of change in concentrations and contents of nitrogen, phosphorus, potassium, magnesium and calcium in fully expanded leaves of young Eucalyptus globulus (Labill.) trees growing in a plantation in southeastern Australia, over a 12-month period beginning at the onset of spring. There was significant net retranslocation of mobile nutrients on a seasonal basis from green leaves, coinciding with continued growth and production of foliage. There was a close positive relationship between initial nutrient content (N, P and K) of the leaf and amount retranslocated, and a tight coupling between N and P retranslocated from leaves. Net retranslocation was significantly correlated with basal area growth increments. Artificial shading of leaves resulted in senescence and reduction in leaf mass. It also induced retranslocation of N, P and K from leaves of different ages and from different position in the canopy. Although the mechanisms underlying the effects of shading intensity on these changes were not elucidated, shading provided an experimental tool for studying retranslocation. Comparison of the results with published data for Pinus radiata (D. Don) grown in the same environment indicated a similarity between the species in patterns of change in foliar nutrient contents and in factors governing foliar nutrient retranslocation, giving rise to unifying principles.     

Patterns of longitudinal within-tree variation in pulpwood and solidwood traits differ among Eucalyptus globulus genotypes

Wood discs were sampled from 6 heights up the stem of 248 trees representing 10 subraces and 116 families grown in an E. globulus base-population progeny trial. The lower stem had the least favourable wood properties for kraft pulpwood and most solidwood applications: bark was thickest, basic density was lowest and kino, decay and shrinkage traits were greatest at or below 12% of tree height. Significant genetic differences at the subrace level were revealed in diameter, bark thickness, basic density, decay and gross shrinkage and at the family within subrace level in diameter, basic density and decay. However, subrace-by-height-category interactions in bark thickness, basic density, decay and gross shrinkage indicated that differences among subraces were dependent on height in these traits. Examination of longitudinal trends revealed some evidence that the zone of thick basal bark extended further up the stem in thicker-barked subraces and that the Southern Tasmania subrace might be less effective than other subraces in restricting the longitudinal spread of decay after infection.     

Heat-induced colour changes of pine (Pinus pinaster) and eucalypt (Eucalyptus globulus) wood

Heat treatment of Pinus pinaster and Eucalyptus globulus wood was carried out by hot air in an oven for 2–24 h at 170–200°C and by steam in an autoclave for 2–12 h at 190–210°C. The colour parameters L*, a* and b* were determined by the CIELAB method on radial, tangential and transverse sections of untreated and treated wood, and their variation with regard to the treatment (ΔL*, Δa* and Δb*) were calculated in percent. For untreated eucalypt wood, lightness (L*) varied between 54.1 and 63.8% with a* between 7.4 and 8.5, and b* between 15.7 and 19.9. For untreated pine wood, L* varied between 67.3 and 76.1%, a* between 6.9 and 7.6 and b* between 16.3 and 24.1. Oven heat-treated wood became darker (ΔL* about 50% for 4% mass loss), and this was more for eucalypt wood under the same treatment conditions. In general, the contribution of red (a*) and yellow (b*) colour decreased with heat treatment. The transverse section of the two species darkened less for both the treatments with small differences between radial and tangential sections. Lightness decrease was related to chemical changes; with good correlations with glucose (R ² = 0.96), hemicelluloses (R ² = 0.92) and lignin (R ² = 0.86). As regards colour, the heat treatments showed an interesting potential to improve the wood quality for solid timber products from pine and eucalypt.     

Nondestructive sampling of Eucalyptus globulus and E. nitens for wood properties. III. Predicted pulp yield using Near Infrared Reflectance Analysis

  Within-tree variation in kraft pulp yield, predicted using near infrared reflectance analysis, was studied in thirty trees of E. globulus and fifty trees of E. nitens to develop a non-destructive sampling strategy. Trees, aged 5 to 9 years, were sampled across a range of sites in southern Australia. Simulated core samples were removed at six fixed heights easily accessible from the ground (0.5, 0.7, ... 1.5 m) and at seven percentage heights (0, 20, 30, ... 70%). Whole-tree values, calculated from percentage height data, were correlated with the core data to determine the optimal sampling height. Core samples were found to be good predictors of whole-tree pulp yield for E. globulus, with simulated cores taken from the recommended sampling height (1.1 m) explaining more than 50% of variation in whole-tree pulp yield. Results for E. nitens were variable with large site differences apparent. On high quality sites, core samples from the recommended sampling height (0.9 m) were good predictors of whole-tree pulp yield, explaining around 60% of the variation. On poor quality sites, cores were poor predictors of whole-tree pulp yield. Radial orientation of cores was not important and predicted pulp yield was not related to tree size, basic density or fibre length. To estimate stand mean pulp yield to an accuracy of ±1% would require sampling 6 trees of E. globulus and 4 trees for E. nitens using either multiple discs or core samples. A single sampling height (1.1 m) is recommended for sampling for basic density, fibre length, fibre coarseness and predicted pulp yield in E. globulus. For E. nitens the recommended sampling height for basic density and fibre length is 0.7 m and 0.9 m is recommended for predicted pulp yield on good quality sites. Received 17 September 1998     

Role of Eucalyptus globulus wound wood extractives: evidence of superoxide dismutase‐like activity

Superoxide dismutase‐like activity of crude Eucalyptus globulus extracts obtained from new wound wood was measured using the water‐soluble tetrazolium salt (WST)‐1 assay. This in vitro assay determined the activity of superoxide radicals scavenging in a xanthine oxidase system. The 50% inhibition (IC₅₀) of formazan formation was estimated for fractionated samples and purified compounds isolated from the crude wound wood extract, i.e. engelitin and pedunculagin. Standards of gallic acid and pentagalloyl glucose were also measured. Fraction II as well as the compounds pentagalloyl glucose and pedunculagin showed the highest levels of antioxidant activity. Subsequent analysis of fraction II by high‐performance liquid chromatography (HPLC) coupled with negative ion electrospray mass spectrometry revealed the fraction to be dominated by hydrolysable tannins including pedunculagin, di‐, tri‐ and tetragalloylglucoses. These preliminary results provide some evidence for an antioxidant role of secondary metabolites in tree wound repair and defence.     

Effects of site on fibre, kraft pulp and handsheet properties of Eucalyptus globulus

? Eight-year old trees from two Eucalyptus globulus Labill. clones planted across three different sites in Tasmania, Australia, were sampled for wood and kraft pulp/handsheet properties.

? Site had a significant effect on all measured properties. Compared with the poor site (Parkham) the wood from the good site (West Ridgley) had on average 11 % lower wood density. The poor site had also greater microfibril angles, shorter fibres at lower pulp yields.

? The handsheets produced with pulp from the poor site resulted in comparatively higher bulkiness, lower burst, lower tear and tensile indices, lower zero span tensile strength, but higher opacity, higher light scattering and higher surface roughness. Significant height effects were found with all wood properties, and also with tear index, zero span tensile strength and opacity.

? Discriminant analysis showed that for 76 out of 100 handsheets the raw material source, i.e. growth site, could be predicted correctly using a set of handsheet properties with tear index and bulk index being most prominent.

? This is unique evidence that site conditions are strongly reflected in handsheet properties produced from Eucalyptus pulp.

     

蓝桉、直干桉综合丰产技术试验示范

试验林采用正交设计，因素为树种、整地方式、密度、施肥，各因素取３个水平，３次重复。用生长量、生物量与投入产出进行评价。试验结果：３．５年生蓝桉、直干桉幼林最佳处理平均高９．５ｍ，平均胸径８．９ｃｍ，每ｈｍ２蓄积量７０．５１２６ｍ３，最佳处理比最差处理树高大２８．４％，胸径大３４．９％，蓄积量大１８３％。用已取得的技术成果营造的示范林，３．５年生平均高９．８ｍ，平均胸径６．５ｃｍ，累计产桉叶２．４３万ｋｇ／ｈｍ２，３年生左右，通过桉油及薪柴的收入可以回收全部造林及加工成本。     

尾叶桉家系木材性状的变异研究

对75个月生32个尾叶桉家系的6个与木材相关的性状进行了研究.6个木材性状在家系间存在显著或极显著差异,说明通过家系选择可以获得性状优良的家系/无性系;木材基本密度、木材含水量、纤维宽、纤维长宽比与生长、形质性状间的相关关系不显著,表明该4个研究性状能各自遗传,可以分别独立选择;纤维长与树高、胸径及单株材积相关关系达到显著或极显著水平,说明纤维长度随树龄增长而增加,材性逐渐得到改善;所有木材性状间的遗传力均在0.5左右,说明各性状受到中等水平的遗传控制;水分含量、基本密度、树皮厚度、纤维长宽比性状的遗传变异系数较高,表明尾叶桉家系在4个性状上具有较丰富的遗传变异,进行性状遗传改良可获得较高遗传增益,按25%入选率,预期遗传增益可达5.68%～17.66%.     

Mineral nutrition and adventitious rooting in microcuttings of Eucalyptus globulus

We characterized the adventitious rooting response of Eucalyptus globulus Labill. to various concentrations of calcium, nitrogen, phosphorus, iron, manganese, zinc, boron and copper. The parameters analyzed were percent rooting, root number, root length and mean rooting time. Root number and root length were significantly affected by mineral nutrition, whereas mean rooting time and rooting percentage seemed to be closely related to auxin availability. Root number was affected by calcium, nitrogen source and zinc, whereas root length was influenced by concentrations of phosphorus, iron and manganese, and by nitrogen source. Based on these results, we evaluated various combinations of several concentrations of these minerals in each rooting phase. Cuttings that were rooted in an optimized mineral nutrient medium and acclimatized to ex-vitro conditions for two months showed significantly higher survival after transplanting and drought stress than cuttings rooted in basal medium and treated in the same way.