In this preliminary study, the influence of industrial emission on the wood quality of Norway spruce was evaluated. Intrinsie wood quality determining properties: ring width (RW), mean annual density, percentage annual 1atewood and the product of (RW × (maximumminimum density)) appear to be affected by the emissions of a fertiliser factory adjoining the stands studied. Fluctuations in the performance of these intrinsic wood properties coincide with the start of production by the factory and a change in the manufacturing process.
Wood quality is affected by silviculture, which includes factors such as stand density control and genetics. In the present study, the effects of initial spacing on the general wood quality and lumber quality of sugi wood (Cryptomeria japonica D. Don) were examined. Logs of 35-year-old sugi were cut from four stands with different initial spacing (A: 2.6 by 2.6 m, 1,500 trees/ha; B: 1.8 by 1.8 m, 3,000 trees/ha; C: 1.3 by 1.3 m, 6,000 trees/ha; D: 1.0 by 1.0 m, 10,000 trees/ha). Trees from stand A showed significantly larger values in annual ring width than trees from the other stands. However, there were no significant differences in the wood basic density, the length of latewood tracheids, and the microfibril angle of the S2 layer among stands. On the other hand, initial spacing affected the lumber quality. The average diameter of knots was significantly larger in stand A than in the other stands. In addition, the dynamic Young's modulus, the modulus of rupture, and the modulus of elasticity in static bending increased with the decrease in the initial spacing from 2.6 by 2.6 m to 1.3 by 1.3 m.
The wood quality parameters of cell wall
percentage, tissue proportions and basic specific
gravity were determined for three naturally
and nine plantation grown trees of Light
Red Meranti (Shorea leprosula and S. parvifolia).
Pinus radiata D. Don (radiata pine) wood can develop a wood quality defect called ‘intra-ring checking’ (checks) during kiln drying. A study was conducted to examine if rays and resin canals were the initiation sites of checks, and if the presence of the rays and resin canals increased the susceptibility of radiata pine wood to checking. The structural features associated with checking were observed in images of thirteen oven-dried radiata pine disks. Six of the sixty checks observed were associated with rays and resin canals. It is clear from the observations that rays and resin canals could not be the primary sites for check development. A comparative study showed some differences between the checked and non-checked wood with respect to rays and resin canals. Checked wood showed a higher amount of tissue area occupied by rays than the nonchecked wood. Hence, it is possible that rays can influence the tendency of wood to check. Such a relationship was not seen with respect to resin canals. However, a difference in the arrangement of resin canals was observed between checked and non-checked wood. Checked wood showed a scattered arrangement of resin canals, while the non-checked wood showed a linear arrangement.
The anatomical, physical and mechanical properties of non-coppiced and coppiced (after first felling) wood of Eucalyptus tereticornis were studied to evaluate their quality and to recommend it for various end uses. The pith to periphery variation in specific gravity, fibre length, fibre diameter, fibre lumen diameter, double wall thickness, vessel diameter and vessel element length were investigated in both types of wood. Correlation coefficients between anatomical characteristics and specific gravity and among anatomical characteristics were established. The results of physical and mechanical properties indicate that the timber from both non-coppiced and coppiced wood can be classified as very heavy, strong, tough, very hard but liable to warp and crack badly. The studies suggest that there is no significant difference in anatomical and mechanical properties of non-coppiced and coppiced wood suggesting their timbers can be utilized for similar purposes.
Effects of nitrogen (N) and phosphorus (P) fertilizers on average fibre radial diameter, tangential diameter, wall thickness and number of fibres per unit area were studied over 7 years of growth in radiata pine. Stands were in mid-rotation, thinned and treatments replicated 4 times at 3 sites. Compared to a thinned, unfertilized control, N decreased and P increased fibre radial diameter. Only N decreased fibre radial diameter, thereby increasing the number of fibres per unit area. All fertilizer treatments decreased fibre wall thickness. Responses in ring width and fibre properties, other than fibre tangential diameter peaked 2 years following fertiliser application, before gradually disappearing after 4–5 years. Fertilizer effects on fibre properties diminished at different rates, causing significant interactions with time. Ring width had little effect on density. Changes in density and fibre coarseness were attributed to changes in fibre wall thickness more than fibre radial diameter and tangential diameter. The largest decrease in density and fibre coarseness in the combined N and P treatment was explained mostly by thinner walls.
Urban pollution is one of the current environmental problems which most threatens the human and environmental health. In a fast-changing world, trees stand out among the sessile organisms that withstand the variations imposed by the environment throughout their lifespan. Thus, trees have become important objects of study in the evaluation of phenological, physiological and/or morphological plasticity. Previous studies have demonstrated the impact of urban environment on cambium anatomy and dendrochronology of Ceiba speciosa (Malvaceae), a native species of the Atlantic Forest. In the present study, our objective is to evaluate the impact of the urban environment on wood structure and consequently on the hydraulic architecture of Ceiba speciosa. Wood samples were collected by a non-destructive method, processed and analyzed according to the usual techniques for plant anatomy. Samples were collected in two sites: the first, an important forest remnant of the Atlantic Forest, and the second next to Avenida Brasil, the largest avenue in Rio de Janeiro, the fourth largest city in Latin America. Trees showed plasticity in seven anatomical features and significant differences in wood structure between both groups studied. Urban trees have lower hydraulic conductivity, shorter vessels and fibres, and larger, more frequent rays. These features demonstrate that in stressful situations, such as those observed in urbanized environments, Ceiba speciosa invests in more safety for water transport and in lower wood resistance, with a trade-off between high production of cells of low energy cost and providing storage of water and metabolic products for unfavorable periods.
The variation of specific gravity, ring width, tracheid length and tracheid crosssectional dimensions was studied among the remote natural forests of Cupressus sempervirens var. horizontalis Gord. of the Greek islands Crete, Rhodes and Samos.