Absence of bacteria from the heartwood of eucalypt species.

Despite the use of both broth and agar culture techniques, bacteria were not isolated from clear or decaying heartwood tissues in any of the five stems representing each of Eucalyptus bancroftii, E. dealbata, E. macrorhyncha and E. sideroxylon. Bioassays suggested that the low pH conditions (<4) and/or abundance of extractives (ca. 10% w/w) may contribute to the exclusion of bacteria (which flourish in the sapwood) from heartwood tissues. [ABSTRACT FROM AUTHOR]