Chemical analysis of the wood and bark of different eucalyptus types before and during the shiitake cultivation

Abstract

Chemical composition of the wood and bark of seven eucalyptus species (E. saligna, E. grandis, E. urophylla, E. camaldulensis, E. citriodora, E. paniculata and E. pellita) and three eucalyptus clones (E. grandis x E. urophylla hybrids) were evaluated before and during log cultivation of shiitake (Lentinula edodes) strains LE-95/01 and LE-96/18. Each shiitake strain was inoculated into 9 logs, 1m in length and 9 to 14 cm in diameter, of each type of eucalyptus. The experimental design was complete randomized, with 20 treatments and 9 repetitions, with each log .corresponding to a repetition. Logs were kept in a greenhouse, at 25 °C ± 5 and relative air humidity between 60-80 %, for 12 months. Chemical composition was determined in newly cut disks and barks wedges of eucalyptus (without inoculation of L. edodes strains) and disks wedges removed from inoculated logs after 8 of incubation. Results showed differences in holocelluose, lignin and total extractives contents in wood and bark after cutting and after 8 months of incubation in the eucalypt species and clones. The highest hollocelullose decomposition rate in wood, over the time, occurred in E. saligna (5.5%), pointing out this species as the most favorable for micelial development of L. edodes, whereas for bark, it occurred in clone 24 (22.2%). E. camaldulensis presented the highest lignin decomposition rate in wood (6.8%), over the time. Bark of E. grandis showed the highest lignin decomposition (21.9%) among the tested eucalyptus. L. edodes degraded more holocellulose and lignin from bark than from wood, indicating the importance of this material. Bark of most eucalyptus types showed lower holocelluose content, higher total extractive content and lignin contents similar or higher compared with wood. The factor eucalypt type (species or clones) showed higher effect than L. edodes strains on degradation of holocelluose and lignin.