Colorimetric changes in two radial positions caused by wood-decaying fungi in wood of seven eucalypt species

Abstract

This research aimed to determine the colorimetric alterations of the wood of seven eucalypt species caused by fungal decay in two positions in the pith–bark direction (median heartwood and transition region, containing the heartwood and sapwood), during wood exposure to agents that cause deterioration. Two 12-year-old trees were randomly sampled for each species, from which a 2.20 m log was removed from the first basal section of each tree for biological assays with brown and white rot fungi and measurements of colorimetric variables. As a sampling strategy for the assays, two positions were evaluated in the pith–bark direction (1 = median heartwood and 2 = heartwood and sapwood transition region). The data analysis used the F test from analysis of variance (ANOVA) and the Scott–Knott test to compare means (p < 0.05). Regarding eucalypt species, the greatest mass loss caused by the fungus Rhodonia placenta was in the wood of Eucalyptus grandis (38.13%) in the median heartwood position, which also occurred with the fungus Gloeophyllum trabeum, with mass loss of 24.76%. The wood from E. pellita was less susceptible to colorimetric alteration of the wood in the median heartwood (6.29), followed by wood from E. saligna (8.51) and E. robusta (7.42). The correlations related to the colorimetric variation resulting from the fungal attack showed that only the attack caused by Gloeophyllum trabeum did not show a relationship between the change in wood colour and the mass loss values.