Polyflavonoid tannins complex easily and rapidly with metal ions such as copper, chromium, and arsenic. such complexes in high-tannin-containing CCA treated hardwoods might result in essentially under-treated timber. Four aspects of this interaction were investigated: 1) The relationship between tannin contents of seven hardwoods (Betula pendula, Alstonia scholaris, Fagus sylvatica, Liquidambar styraciflua, Nothofagus menziesii, Platanus acerifolia and Tilia vulgaris) and one softwood (Pinus radiata) and% Cu toxic thresholds; 2) Determination of tannin distribution within cell wall layers; 3) The field performance of Pinus radiata treated with solutions of bark tannin, then CCA; 4) TEM/EDAX studies on CCA loadings in the S2 layer of tannin/CCA treated Pinus radiata tracheids. Our observations suggest that by themselves tannins have a minor influence on field performance of CCA-treated hardwoods.

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