A single Norway spruce tree (
) was manually fractionated into heartwood, sapwood, juvenile wood and branches. These fractions were chemically pulped, individually, in laboratory scale. The pulps ...were characterized and investigated in relation to dewatering behavior and sheet strength properties. An unbleached and unbeaten commercial kraft pulp from softwood fibers was used as a reference, and the fractionated pulps were within the same range in all tested properties. The fractionated pulps were then compared with each other, and fiber characteristics were used to explain differences in dewatering and strength. Heartwood pulp results in stronger and stiffer papers that are harder to dewater. Sapwood pulp gives more open network structures resulting in easy dewatering and high air permeance, although with lower strength properties compared to heartwood. Pulp from Juvenile wood gives s quite strong but brittle sheets, with efficient dewatering. Pulp from branches gives paper sheets with efficient dewatering, air permeance and relatively high elongation of break but lower strength. The results show that there is definitely potential for utilizing more parts of the trees for pulp and paper making, especially when tailoring the raw material origins after preferred paper properties.
Carbon fraction (CF) of trees is essential for quantifying forest carbon (C) stocks. Considerable attention has been paid to CF variations at various levels with the exception of inter- and ...intra-growth rings. Herein, the inter- and intra-growth ring variation of CF in
was investigated. Elemental analysis was performed to obtain CF values of the earlywood and latewood in each growth ring of the xylem. Patterns of CF variation at the growth ring level were evaluated using mixed-effect models. The results showed that latewood CF, 50.6 %, was significantly higher than earlywood CF, 49.9 % (
< 0.01). In particular, inter-growth ring variations of CF differed between heartwood and sapwood, as well as between juvenile wood and mature wood. CF values decreased nonlinearly with cambium age toward the heartwood or juvenile wood, with estimated least-squares means of 50.4 % and 51.8 %, respectively. While CF values were almost unaltered in sapwood, and slightly decreased in mature wood, with estimated least-squares means of 50.0 % and 50.2 %, respectively. It indicates that patterns of CF variation between juvenile wood and mature wood are important to estimate the C stock of
. This research provides insights into C uptake dynamics to support forest management and wood utilization.
The main objective of this study was to reveal variations in the wood structure and to define the location of the boundary between juvenile and mature wood Larix decidua Mill. from fast growing tree ...plantations. To reach these findings, the samples of wood from four short-rotation plantations in Central Europe (Poland) were selected and compared. The procedure used to determine the demarcation point between juvenile and mature wood resulted in strong correlations between the width of growth rings and the initial cambial age. It was found that the structure of wood from fast-growing trees differs from commercially available timber. The wood derived from plantations revealed wider annual rings than wood from natural forests. The analysis of the variability of wood structure resulted in defining the location of the boundary between juvenile and mature wood. Based on the analysis of structure of annual rings, the boundary of juvenile wood in fast-growing larch is placed between the 12th and 15th annual ring. The investigated material contained high proportions of juvenile wood, which makes up more than 70% of trunk volume. On the microscopic level, no visible changes, indicating the presence of a mature wood zone, were found.
This study aimed to examine the drying in Eucalyptus wood in different directions and regions. Flow rates of free (FRFW), bound (FRBW), and total water were calculated in three directions. FRFW in ...the transversal direction demonstrated higher rates for the internal region. FRFW in the longitudinal direction was 1.7 times higher than in radial and 2.4 times higher than in tangential. FRBW in the tangential and radial directions was equal. FRFW was ∼14 times higher than FRBW. Correlations between FRFW and FRBW were inversely proportional. The results can help in the drying optimization of Eucalyptus and indicate parameters for its use in industries.
Juvenile wood (JW) and mature wood (MW) have distinct physical and chemical characters, resulting from wood formation at different development phases over tree lifespan. However, the regulatory ...mechanisms that distinguish or modulate the characteristics of JW and MW in relation to each other have not been mapped. In this study, by employing the
Populus
trees with an identical genetic background, we carried out RNA sequencing (RNA-seq) and whole genome bisulfite sequencing (WGBS) in JW and MW forming tissue and analyzed the transcriptional programs in association with the wood formation in different phrases. JW and MW of
Populus
displayed different wood properties, including higher content of cellulose and hemicelluloses, less lignin, and longer and larger fiber cells and vessel elements in MW as compared with JW. Significant differences in transcriptional programs and patterns of DNA methylation were detected between JW and MW. The differences were concentrated in gene networks involved in regulating hormonal signaling pathways responsible for auxin distribution and brassinosteroids biosynthesis as well as genes active in regulating cell expansion and secondary cell wall biosynthesis. An observed correlation between gene expression profiling and DNA methylation indicated that DNA methylation affected expression of the genes related to auxin distribution and brassinosteroids signal transduction, cell expansion in JW, and MW formation. The results suggest that auxin distribution, brassinosteroids biosynthesis, and signaling be the critical molecular modules in formation of JW and MW. DNA methylation plays a role in formatting the molecular modules which contribute to the transcriptional programs of wood formation in different development phases. The study sheds light into better understanding of the molecular networks underlying regulation of wood properties which would be informative for genetic manipulation for improvement of wood formation.
L.,
Du Tour,
Ledeb., and
Ledeb. are important forest tree species in Mongolia. The radial variations of wood anatomical characteristics, physical and mechanical properties were evaluated by linear or ...nonlinear mixed-effects models for effective wood utilization of those of conifers. Many of these wood properties either increased or decreased from the pith to the bark and then became nearly constant based on the selected models. The properties of mature wood were estimated by nonlinear mixed-effects models, suggesting that
and
are suitable as structural lumber,
can be used for furniture and other interior products, and
is suitable for structural lumber as well as for furniture or interior products.
The Brazilian bioenergy industry is well developed and has numerous highly productive Eucalyptus spp. clones, the wood of which may suit the timber industry. We screened the mechanical wood ...properties of six bioenergy Eucalyptus spp. clones from young forests to find ones suitable for the timber industry. We evaluated shear strength, parallel compressive strength, strength and stiffness on static bending, and wood density. Eucalyptus camaldulensis clones had low strength and stiffness for their wood density and are less suitable for timber products. However, clones from E. urophylla and E. urophylla × E. grandis had specific strength and stiffness close to the values reported for mature Eucalyptus wood. Their average density ranged from 0.54 g cm
−3
to 0.68 g cm
−3
and, while the lightest wood had properties close to those of mature Pinus elliottii trees, the clone with the densest wood produced material similar to mature E. urophylla. We conclude that these clones have distinct wood properties, each with different potential applications. With better understanding of this timber source, young clonal Eucalyptus forests could be an asset to the timber industry in Brazil, substituting pine wood and providing raw material close to the main consumer markets.
This work examined differences encountered when machining juvenile wood vs. mature wood. Difference in the blunting of the cutting tool when processing types of juvenile and mature wood from pine ...(Pinus sylvestris L.) and poplar (Populus tremula L.) were studied. The experimental model process included milling at various feed (2.5 and 15 m∙min-1) and cutting speeds (pine 20 m∙s-1, poplar 30 and 60 m.s-1), at various angle geometries (rake angle, cutting edge, and clearance angle). The blunting of cutting edge was measured after milling at 100, 300, and 500 meters on milling machine with the lower spindle. The results showed that milling of juvenile wood gives a longer technical lifetime for cutting instruments than milling of mature wood.
Low-field nuclear magnetic resonance (LFNMR) relaxometry was applied to determine the spin-spin relaxation time (
) of water-saturated Norway spruce (
(L.) Karst.) specimens cut from mature sapwood ...(sW) and mature and juvenile heartwood (hW), where earlywood (EW) and latewood (LW) were separated. In combination with quantitative wood anatomy data focusing on the void volumes in various morphological regions, the NMR data served for a more reliable assignment of free-water populations found in water-saturated solid wood. Two free-water populations were identified within most sample types. One was assigned to water in the tracheid lumen and the other to water inside bordered pits. Whether water in the ray cell lumina was included in one or the other of these two populations depends on the curve-fit method applied (continuous or discrete). In addition,
differences between the different tissue types were studied and, for comparison, sorption isotherms were measured by means of a sorption balance. There was a significant difference between EW and LW as well as between juvenile wood and mature wood in terms of
related to the cell wall water. However, no differences were seen between the sorption isotherms, which indicates that the observed
differences were not due to differences in cell wall moisture content (MC).
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