Genetic variation and selection of 10-year-old Eucalyptus camaldulensis based on wind damage index and wood properties

Typhoons are becoming frequent and intense with ongoing climate change,threatening ecological security and healthy forest development in coastal areas.Eucalyptus of a predominant introduced species in southern China,faces significant growth challenges because of typhoon.Therefore,it is vital to investigate the variation of related traits and select superior breeding materials for genetic improvement.Variance,genetic parameter,and correlation analyses were carried out on wind damage indices and eight wood proper-ties in 88 families from 11 provenances of 10-year-old Euca-lyptus camaldulensis.The selection index equation was used for evaluating multiple traits and selecting superior prov-enances and family lines as future breeding material.The results show that all traits were highly significantly differ-ent at provenance and family levels,with the wind damage index having the highest coefficient of genetic variation.The heritability of each trait ranged from 0.48 to 0.87,with the wind damage index,lignin and hemicellulose contents,and microfibril angle having the highest heritabilities.The wind damage index had a positive genetic correlation with wood density,a negative correlation with lignin content,a negative phenotypic correlation and a negative genetic correlation with microfibril angle.Wind damage index and genetic progress in the selection of eight wood traits varied from 7.2%to 614.8%.Three provenances and 12 superior families were selected.The genetic gains of the wind damage index were 10.2%and 33.9%for provenances and families,and these may be starting material for genetic modification for wind resistance in eucalyptus and for their dissemination to typhoon-prone coastal areas of southern China.

Vacuum press drying studies on two fast-growing Indian wood species

Two fast-growing Indian species, Melia composita Benth. and Eucalyptus tereticornis Sm., which have different sets of physical properties, were dried together in a vacuum press dryer(VPD) under two drying conditions,i.e., above boiling point(ABP) and below boiling point(BBP). The ABP and BBP conditions were maintained by keeping the temperature constant at 75 ℃ and maintaining two pressure levels: 300 mm of Hg(ABP) and 450 mm of Hg(BBP). In order to understand pressure conditions at the core during vacuum drying, a cylindrical brass pipe was inserted in both wood cores and attached with pressure gauges placed outside of the VPD. The results indicate that the Melia wood core attained equilibrium pressure immediately with the pressure of VPD, while Eucalyptus attained it very slowly, reaching equilibrium at later stages of drying when cracks and checks advanced to the core.The drying rate was higher for Melia than Eucalyptus under both drying conditions. The drying rate of Melia(ABP) was higher than Melia(BBP), however, the drying rate for Eucalyptus(ABP) was not significantly different from the BBP drying rate.

Use of the pilodyn for assessing wood properties in standing trees of Eucalyptus clones

The effectiveness of pilodyn was tested in evaluating wood basic density, outer wood density, heartwood density, and modulus of elasticity （MoE） at 22 four-year-old eucalyptus clones in Guangxi, China. Results indicated that the mean value ranged from 9.44 to 15.41 mm for Pilodyn penetration, 0.3514 to 0.4913 g.cm^-3 for wood basic density, and 3.94 to 7.53 Giga Pascal （GPa） for MoE, respectively. There were significant differences （1% level） in pilodyn penetration between different treatments, different directions and among the clones. Generally strongly negative correlations were found between pilodyn penetration and wood properties, and the coefficients ranged from -0,433 to -0,755. Our results, together with other studies, suggest that the use of pilodyn for assessing wood density and MoE was confirmed as a possibility.

Variation of basic density,calorific value and volumetric shrinkage within tree height and tree age of Ugandan grown Eucalyptus grandis wood

Insufficient knowledge on Ugandan grown Eucalyptus grandis W.Hill ex Maiden wood properties,high demand,and processing challenges led to a study into its physical properties.We obtained the variation of basic density(BD),calorific value(CV)and volumetric shrinkage(VS)within tree height and tree-age of E.grandis,and its appropriate use based on these properties.Trees with good boles were harvested from Kabarole District in western Uganda to produce specimens as prescribed by British Standards and ASTM standard wood testing procedures.Secondary data reviews and statistical analysis using ANOVA,Tukey’s test and multivariate analysis were done to obtain property estimates and their variation within trees and amongst tree ages.The mean BD of E.grandis is 413.6,380.5,471.0,and 501.1 kg m^(−3)at 3,6,9,and 12 years,respectively,showing significant increase with tree age(p=0.003).The pattern of BD with tree height showed a reduction with tree height although with higher values in the middle portion of the tree.The CV increases(p=0.014)with tree age and reduces with tree height with values of 14,560.32,15,447.3,16,079.11,and 16,932.6 kJ kg^(−1)at 3,6,9,and 12 years,respectively.The percentage VS was 11.02,9.84,12.31,and 14.45 for 3-,6-,9-,and 12-year-old trees,respectively,and it did not vary significantly(p=0.088)with tree height.Basing on these property values,E.grandis wood could be used for scaffolding,light constructions and fuel wood production.Its seasoning needs to be longer with well monitored drying schedules to reduce seasoning defects caused by the high VS.Further studies on strength properties,seasoning schedules,panel products properties and tree-age chemical variations would improve the knowledge about its wood quality and would enhance its efficient utilization.

Adsorption of Natural Aluminium Dye Complex from Silk-Dyeing Effluent Using Eucalyptus Wood Activated Carbon

Two activated carbons with controlled pore size were prepared from Eucalyptus wood by physical activation with carbon dioxide, giving the BET surface area and pore volume of738 m2/g and0.39 cm3/g, and921 m2/g and0.53 cm3/g for the carbon sample AC1 and AC2, respectively. These activated carbons were then used to remove the residual dye left after the silk-dyeing process. The dye solution used for adsorption study was a cationic aluminium dye complex of [Al(brazilein)2]+ derived from a mixture of alum and extract of the heartwood of Ceasalpinia sappan Linn., with initial dye concentration of 220 mg/l. Effects of adsorbent dosage, adsorption time and temperature in the range of 25℃40℃ on dye adsorption were investigated. It was found that the adsorption kinetics of this dye complex was best described by the pseudo-second order model. Adsorption isotherms of this dye complex were well fitted by Langmuir isotherm equation. The adsorption capacities for the uptake of this dye complex at 25℃, 30℃ and 40℃ were 718.7, 1240.4 and 1139.5 mg/g and 1010.5, 1586.1 and 1659.0 mg/g for carbon sample AC1 and AC2, respectively. From these results, it can be concluded that activated carbon containing a higher proportion of mesopores gave better dye removal efficiency, emphasizing the fact that a proper pore size distribution of carbon adsorbent is crucial for the effecttive removal of relatively large size of the dye molecules. Thermodynamic parameters, including free energy, enthalpy and entropy of adsorption, were also determined. The adsorption enthalpies for the removal of this dye complex of AC1 and AC2 were 105.3 and 55.6 kJ/mol, respectively, indicating that the adsorption is an endothermic process. It was found that the adsorption of this dye complex is spontaneous at the temperatures under investigation.

Improvement of wood properties by composite of diatomite and “phenol-melamine-formaldehyde” co-condensed resin

We improved the overall performance of fast-growing poplar by utilizing a low-cost, effective and simple method. The fast-growing poplar was modified by a vacuum-pressure impregnation method with three types of modification solutions composed of phe- nol-melamine-formaldehyde （PMF） co-condensed resin, diatomite, and 3-aminopropyl （diethoxy） methylsilane. We measured the weight percent gain （WPG）, bulking, leaching, anti-swelling efficiency （ASE）, wa- ter-repellent effectiveness （WRE）, and oxygen index of the modified specimens. All of the wood physical properties, which are beneficial for human uses, were significantly improved by the treatment. We improved various characteristics of wood and the oxygen index of poplar above 48.6% after the modification using diatomite and PMF co-condensed resin.

Lignocellulosic Micro and Nanofibrillated Cellulose Produced by Steam Explosion for Wood Adhesive Formulations

The reinforcing impact of Lignocellulosic micro and nanofibrillated cellulose(L-MNFCs)obtained from Eucalyp-tus Globulus bark in Urea-Formaldehyde UF adhesive was tested.L-MNFCs were prepared by an environmentally friendly,low-cost process using a combination process involving steam explosion followed by refining and ultra-fine grinding.Obtained L-MNFCs showed a web-like morphology with some aggregates and lignin nanodroplets.They present a mixture of residual fibers and fine elements with a width varying between 5 nm to 20μm,respec-tively.The effects of the addition of low amounts of L-MNFCs(1%wt.)on the properties of three different adhe-sives(Urea-Formaldehyde UF,Phenol-Formaldehyde PF,and Tannin-Hexamine TH)were studied by the evolution of the pH,the viscosity,and the mechanical properties.Results showed that the viscosity of PF and UF adhesives increased with the addition of L-MNFCs,unlike TH.Meanwhile,the addition led to better mechan-ical behavior for the three adhesives.Particleboards were then prepared using modified UF with L-MNFCs and tested.Results showed that an amount of 1%wt.of L-MNFCs was sufficient to increase the internal bonding by≈67%,the modulus of elasticity by≈43%,and the modulus of rupture by≈29%.

Corrective Interventions to End-Splitting and Surface Cracking in Kenya Grown Eucalyptus grandis Poles

This study determined the effect of three pole pre-drying handling techniques, on end-splitting and surface checking in Eucalyptus grandis poles from highland and low land areas in Kenya. A total of 144 Eucalyptus grandis trees were sampled from two sites;Kericho, representing the wet highlands and Londiani representing the drier lowlands regions of Kenya. Pole samples from both sites were subjected to the three pre-drying handling techniques for the first 30 days after felling and allowed to dry to the required moisture level under observations. The number of end splits and surface checks on each sample pole were counted and the length of the worst ones was measured in millimeters after every 15 days until all the poles reached 25% MC. The sap wood and heart wood ratios were determined from selected samples. Results showed that on the overall, poles from high land areas had the highest sapwood proportions and similarly had the highest number and the longest end splitting and surface checks. On the other hand, pre-drying techniques that allowed felled trees to dry slowly with their foliage intact for the first 30 days of felling produced the best quality poles, with fewer and shallower end splits and surface checks. The study recommended that felling and leaving poles to dry slowly with foliage intact be considered in reducing losses incurred as a result of wood stresses during drying of poles.

Study on Machining Properties of Eucalyptus urophylla×E. grandis:I. Planing and Sanding Properties

The research method in this paper is based on the standard of American Society for Testing andMaterials (ASTM). Planing and sanding are selected to study the machining properties of E. urophylla × E.grandis plantation wood. Moreover, the reasons for machining defects are analyzed. The results show E.urophylla × E. grandis planted in south China is a good species with a great potential for solid woodutilization.

Preliminary Survey of Trunk Growth Strain in Six Eucalyptuses Grown in Southern China

The longitudinal displacement between two reference points upon stress release was measured throgh using the CIRAD-foret one-hole method on a total of 305 trees of 6 eucalyptuses, including Eucalyptus urophylla, E. pellita, E. teriticornis, E. camaldulensis, E. urophylla x E. grandis and E. urophylla × E. teriticornis. These trees were between 3 to 5 years old and are regarded as commercially important plantation species in China. Significant differences in the growth strain and diameter at breast height over bark （DBHOB） were observed between species, provenances and clones of the same age. The data clearly showed that, E. pellita, E. teriticornis and E. camaldulensis （provenance 15025） had higher growth rates but much lower growth strain at the tree surface, in comparison to other species / hybrids / clones. Whilst conclusive recommendations for species selection need to be substantiated with comprehensive studies that include other key wood properties, results of this study have shown trends pertaining to wood quality differences between the six species.

Study on Machining Properties of Eucalyptus urophylla× E.grandis:Ⅱ.Shaping,Boring,Mortising and Turning

The research method of this paper is based on the standards of American Society for Testing and Materials (ASTM). Four items that contain boring, mortising, shaping and turning are selected to study the machining properties of E. urophylla × E. grandis plantation wood. The reasons for machining defects are analyzed. The resultshows thatE. urophylla × E. grandis planted in South China isa good specieswith great potential for solid wood utilization.

Eucalypt Wood Anatomical and Physical Properties and Their Effects on Plywood Veneer Quality

In order to better understand the reasons why eucalypt veneer checks easily and severely, wood samples of three eucalypt species were selected, and their anatomical and physical properties were examined according to conventional methods and the national standards. The effects of variances in cell wall thickness of wood fibre and vessel, and diameter of the cell lumen as well as the tissue ratio on the quality of plywood veneer were analysed. The results show that： 1） There is a great difference in fibre cell wall thickness and diameter of the cell lumen between early wood and late wood of Eucalyptus delegatensis. 2） E. obliqua has a high wood fibre tissue ratio and the thickest fibre cell wall, but the difference inthe fibre cell wall thickness between early wood and late wood is the smallest. 3） The wood fibre tissue ratio of E. regnans is smaller than that of E. obliqua, and its wood fibre cell wall isthe thinnest and there is only a very small difference in fibre cell wall thickness between early wood and late wood. The difference inthe diameter of wood fibre cell lumen among early wood, transition area and late wood is also small： 4） E. delegatensis has the highest tangential shrinkage rate and radial-tangential shrinkage rate, andE. obliqua has the lowest. It is the variability of wood anatomical properties of these species that cause the difference in the veneer shrinkagei and then affects plywood veneer quality.