Sampling of the bole and effect of the bark on the quality of eucalyptus wood for the production of MDF (Medium Density
Fiberboard)
Name: STÉFFANY DE LIMA ARAUJO
Publication date: 29/02/2024
Examining board:
Name |
Role |
|---|---|
| GRAZIELA BAPTISTA VIDAURRE DAMBROZ | Advisor |
Summary: Knowledge of the characteristics of young eucalyptus used in industries is essential to infer the quality of the products and waste generated. Due to the natural variability of wood, good accuracy of results takes into account the sampling used and, with the
large use of eucalyptus in the wood industries, there is also a large generation of waste, especially the bark. Some companies, such as reconstituted wood panel products, use this type of disposal in the manufacturing process. Therefore, the shell should not be treated only as a destruction, but should be evaluated in more detail. That said, the objectives of this dissertation were to evaluate sampling strategies along the tree trunk to determine the basic density of eucalyptus clone wood and evaluate the influence of the presence of bark on the properties of eucalyptus wood through the production of Medium Density Fiberboard. The wood of four eucalyptus clones were studied, two hybrids of Eucalyptus urophylla x Eucalyptus grandis, one Eucalyptus grandis and one Eucalyptus urophylla, aged 6 years, from a commercial plantation in the municipalities of Lençóis Paulista and Agudos, state of São Paulo, Brazil. Five trees were collected per clone, according to the average planning diameter predicted by the forest inventory. Discs were removed along the commercial shaft, in addition to a sample at the position of the diameter at breast height, which were divided into sampling strategies. The properties evaluated were: proportion of heartwood and bark in the discs, basic density, chemical composition, pH and ash for bark, wood with and without bark. The average density between samples ranged from 476.69 to 449.61 kg m-3. The DBH corresponded to 91.85 to 99.74% of the general bole average, depending on the clone and sampling strategy used. The base-top sampling strategies analyzed did not show significant differences between them, only the one that considers only the DBH was different from the others. Alternative 1 sampling satisfactorily estimated the average density considering all clones as a single material, which is the best strategy
for measuring basic density under the conditions given in the present study. The sampling positions from 50% of the commercial height of the bole were better related to the basic density. The proportion of bark varied from 8.22 to 10.25%, while the
proportion of heartwood ranged from 26.98 to 36.16%. The basic density of wood was 455 to 502 kg m-3, for wood with bark it ranged from 447 to 483 kg m-3, for bark the range was 342 to 368 kg m-3. The mixture of wood and bark for the evaluated
eucalyptus clones was not enough to significantly modify the basic density, chemical composition, pH and ash of the wood. The ash and extractive content were the wood properties most impacted by the presence of bark. Most of the technological properties
analyzed in eucalyptus bark were different from wood with and without bark.
Keywords: Samples; Basic density; Planted forest; Physicochemical properties; Variability
