Changes in heartwood and density of eucalyptus wood as a function of age and planting spacings
Name: LOURDES MARIA HILGERT SANTOS
Publication date: 28/02/2019
Advisor:
Name |
Role |
|---|---|
| GRAZIELA BAPTISTA VIDAURRE | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| GILSON FERNANDES DA SILVA | Co advisor * |
| GRAZIELA BAPTISTA VIDAURRE | Advisor * |
| MICHEL PICANÇO OLIVEIRA | External Examiner * |
Summary: One of the forms of differentiation of the wood of the trees is the presence of heartwood and sapwood. The aim of this study was to analyze changes in the heartwood and density of eucalyptus wood at different ages and planting spacings. Trees of the Eucalyptus grandis x Eucalyptus urophylla clone planted in three spacing (3x1, 3x2 and 3x3 m) were sampled at six different ages (14, 27, 32, 53, 64 and 76 months). For quantification of the heartwood, the weighted average of the heartwood volume obtained by measuring the total area and heartwood of the discs along the stem of the trees was performed. The apparent density of the wood of heartwood and sapwood was determined by X-ray densitometry. Percentage, volume and density of the heartwood, and density of the wood were correlated with the different growth rates. The beginning of the process of cernification was verified between 32 and 53 months of age, regardless of spacing, with the use of the Dimethyl yellow indicator and the presence of vessels obstructed by tylos. The proportion of heartwood doubled with increasing age in the largest spacing and increased about four times in the 3x1 m and 3x2 m spacings. The planting spacings influenced growth rates (diameter, total height and volume), but there was no statistical difference between the percentage of heartwood and the increase in the useful area. The greatest increment in density occurred between the first year of growth (14 months) and the beginning of the cernification (53 months), and posteriorly up to 76 months the increment was smaller. The variation in planting spacing resulted in small increases in density, with the formation of denser wood in a larger useful area. There was no pattern of variation in heartwood and sapwood density between the ages and planting spacings. The annual evaluation made it possible to identify the age that started the formation of the heartwood and the increments in density of eucalyptus wood.
Keywords: heartwood formation; trees age; growth rates; X-ray densitometry; tylose.
