A study of the microbial ecology of copper–chrome–arsenic treated and untreated Pinus radiata and Eucalyptus regnans sapwood ground stakes exposed for a total of [Formula: see text] years is currently being made. The results presented in this report cover the initial colonization period during the first 7 months of exposure. Soft rot in the outer layers of both species of untreated wood occurs after only 1 month in the ground. Treatment with CCA prevents the early attack of pine but is not as effective in the eucalypt, nor does it appear to have a significant effect upon the diversity of microorganisms which colonize the two woods. For the first 2 months Penicillia are the predominating members of the population. Trichoderma viride, Paecilomyces fumo-roseus, and Cladosporium spp. are also frequently isolated. At 4 months more active soft-rotting fungi can be isolated, e.g. Chaetomium globosum and Humicola grisea, together with Fusaria and Phycomycetes. Bacteria colonize the stakes at a very early stage, the population changing little over this initial period of the study. Actinomycetes were not isolated until the wood had been in the ground for a month or more after which their importance in the population has steadily increased. Basidiomycetes were microscopically observed in sections of the stakes but have not been isolated to date.
Examining efficient assisting geotechnology for permeation grouting of ultra microfine cement for soil liquefaction countermeasure