Plantation Teak (Tectona grandis L. Fil) has been tested as a possible source of natural wood preservatives due to the known excellent durability of old-growth teak wood. Field tests (ground proximity termite and above ground simulated decking exposures) were established in Colombia in April 2003 at two different test sites with different climates (Tropical Dry and Rain forest). Teak heartwood extracts were obtained using Soxhlet extraction with chloroform-methanol and methanol-ethanol as solvents, for two different mixtures at three different concentrations. Sapwood stakes of Patula pine (Pinus patula) and Globulos eucalyptus (Eucalyptus globulus) were vacuum pressure impregnated with these extracts, and control stakes were impregnated with CCA Type C and ACQ Type D at two nominal retentions (1 and 4kg/m3). The test sites have been found to be very active for both decay and termites. After only 9 months exposure termite attack has been observed from four species (Nasutitermes, Heterotermes, Triangularitermes, Velocitermes), and several basidiomycetes fungi have also been isolated from the test samples (Trametes, Schisophyllum, Poria). The results show that up to 100% of the samples have been subject to fungal attack, although in most samples only superficial trace attack has occurred in the exposure period. In contrast, termite attack has been rapid, primarily on the eucalyptus samples, which are suffering substantial degradation.

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