RADIAL AND AMONGCLONAL VARIATIONS OF TRANSVERSE SHRINKAGE AND BASIC DENSITY IN 5-YEAR-OLDACACIA AURICULIFORMIS CLONES PLANTED IN VIETNAM

This study investigatedtransverse shrinkages and wood density for Acacia auriculiformis trees from six clones planted in north-central Vietnam. Radial and among-clonal variations of partial and total shrinkages in tangential (respective to Tn and T) and radial (respective to Rn and R) directions, partial and total coefficient of anisotropy (respective to Tn/Rn and T/R), and basic density (BD) were examined. There were significant differences among clones for Rn and R, but no significant differences were found among clones for Tn and T. The lowest average Rn and R were detected in clones Clt18 and Clt26, suggesting that these clones might be more appropriate for breeding programs focused on improving shrinkage traits for sawn timber production. BD is not a good indicator for predicting transverse shrinkages. In contrasts, stress wave velocity measured in standing trees has the potential to be used as a non-destructive method for predicting the transverse shrinkage of A. auriculiformis planted in Vietnam

Wood density and annual ring width of pedunculate oak from stands grown on former agricultural land

The main aim of this study was to determine differences in basic density and average annual ring width of pendulate oak wood collected from trees grown on former agricultural land and on forest land, using a dimensional method. The experiment was carried out in the western part of Poland, near to Poznan, which is in the central part of the European range of pedunculate oak. In our study the average basic density was 0.528 g.cm-3, and the value for former agricultural land was lower by 0.026 g.cm-3 than that for forest land. Differences in basic density values between these two land types were statistically significant. The average annual ring width in samples collected from forest land in our study was 2.48 mm, samples from former agricultural land were characterized by wider average annual rings. The results suggest that there are significant differences in quality of wood from former agricultural land and from forest. However, from view of wood quality and applications the difference is not important.

The importance of using multiple analyses techniques to determine the physical condition of the waterlogged wood near the corroded parts

In this study, three samples taken from the planks of the Yenikapı 29 shipwreck were analysed. Firstly, the maximum water content (MWC) and basic density values of the samples were calculated. MWC of the IK13-1 was 164% and the MWC of the SK6-1 was 87%. Because of these low MWC values, samples could be classified as non-degraded. When the SEM images of these two samples were examined, it was understood that the IK13-1 sample was non-degraded but the SK6-1 sample was penetrated with corrosion product and could not be classified as non-degraded. With these analyses, the XRF method was used to measure the iron amounts of the samples. The iron amount of the SK6-1 was 32.3% and the corrosion accumulation in this sample was also proved with XRF. In order to avoid incorrect results, multiple analysis techniques should be used for determining the physical condition of the waterlogged wood near the corroded parts.

Model of free water in wood

The derived model describes equilibrium in wood as it is placed it water. The model expresses the equality of density of water and coupled term of basic density and moisture content on the other side. The other part of the model is its extension to water in wood. The maximum moisture content is derived from the view point of density definition. Then Archimedes’ principle enables to measure bound water maximum moisture content. The model is applicable to wood of arbitrary wood species and also for different kind of materials as it is documented in the embedded table.

Aboveground biomass basic density of hardwoods tree species

The influence of tree species on basic density of wood, bark and small-wood was investigated here. Experimental material was obtained from 73 trees of 7 tree species, namely alder (Alnus glutinosa (L.) Gaertn.), beech (Fagus sylvatica L.), birch (Betula pendula Roth.), hornbeam (Carpinus betulus L.), Black locust (Robinia pseudoacacia L.), Sessile oak (Quercus petraea (Matt.) Liebl.) and Turkey oak (Quercus cerris L.) from the territory of Slovakia. Wood and bark samples were taken from discs cut from three trunk sections and from small-wood and branch parts coming from tree crowns. The volume of green samples was measured in graduated cylinders with a precision of 1 ml; a dry matter was measured with a precision of 0.01 g. The statistically significant effect has been shown in tree species, biomass fractions and locations on the tree. The average basic density of all species varies from 440 to 650 kg.m-3 for wood, for bark it is 380-670 kg.m-3 and for small-wood outside bark it reaches 490-650 kg.m-3. Alder and Black locust tree species have the lowest and highest wood density, Black locust and Turkey oak of bark and alder and Turkey oak of small-wood.