Variation in the Basic Density of Woods Produced in the Brazilian Semiarid Region Subjected to Different Irrigation Regimes

Abstract

The present work aimed to evaluate the wood of fourteen genetic materials (nine species, between native and exotic, and five clones of Eucalyptus) cultivated under two post-planting irrigation regimes in the Brazilian semiarid region. For each genotype, six trees (11 years old) were selected and subjected to two initial irrigation regimes (up to 12 months and up to 36 months) after planting. Discs of different stem heights were taken: 0% (base), breast height (DBH), 20%, 40%, 60%, 80%, and 100%. Samples were extracted along the radial axis of each disk at three regions (the pith-adjacent region, intermediate region, and bark-adjacent region). Samples were subsequently saturated in water to determine their density via the water displacement method. The irrigation systems caused changes in the pattern of radial and longitudinal variation in the clones regarding the proportion of woody material in the stem. Among the native species, Angico stood out with a high density and little juvenile wood, and Pau d’arco, with a low density and a high rate of juvenile wood. Among the exotic species, Nim presented a high density and a low rate of juvenile wood, and Chichá presented a high rate of juvenile wood and a low density. In the Eucalyptus hybrids, VE38 stood out with a high density. Overall, there was an influence from irrigation management, observed with greater intensity in exotic species for Mahogany and Acacia and for the VE41 and AEC1528 clones of Eucalyptus. The values of basic densities in the trees varied from 0.35 to 0.85 g·cm−3. There was good adaptation of native and exotic species and clones to the planting area in the Semiarid region.

Influence of age and trunk positions on physicomechanical properties of Anthocleista grandiflora Gilg wood

“…The density reduces from the base to the top in studied trees for axial and radial directions. This is a general trend since wood density is usually higher at the base due to the higher compaction of the stump tissues exerted by overlapping cells along the trunk and tree crown [12][13][14]20]. AYARKWA [21] and NIEMZ and SONDEREGGER [22] emphasized that the samples extracted from the top part of the tree have lower density and strength properties in most tree species.…”

“…Density is relevant for applying wood in different industrial sectors [12][13][14]. Analyzing the density variation in the axial and radial direction of the species A. colubrina, C. glandulosa, H. courbaril, and H. impetiginosus native to the Brazilian semi-arid region, SANTOS et al [12] found that in the radial direction, all species presented low-density values in the pith region, regardless of the height at which the samples were taken. This behavior was also observed for coniferous wood in studies by MELO [13] and ZAQUE et al [14], with the highest values found in the trunk's peripheral area.…”