Fumigation of New Zealand grown western red cedar for export markets
B Kreber, G Durbin, D Wilson
The objective of this study was to demonstrate that methyl bromide fumigant penetrates into the centre of western red cedar (Thuja plicata L.) timber to meet the standard for export markets. Kiln dried western red cedar was used and a cavity (50x 30 x 13mm3) was prepared into the centre of each sample board (500 x 200 x 26 mm3 thick). An absorbent sachet used in industry for cross checking that the concentration of methyl bromide meets the standard during fumigation of export commodities was then inserted into the cavity. Two sample boards with individual sachets separated by aluminium foil and positioned at 13 mm below the wood surfaces, were then glued together. After curing of the glue, an aluminium tape was used to seal the four edges of the sample to prevent penetration of methyl bromide through the boards' edges. Fumigation was performed for 24 hours in the laboratory and also in a commercial environment using 80g of methyl bromide/m3 of wood prior to the cross checking of sachets. The results of this study demonstrated penetration of methyl bromide into the centre of kiln dried western red cedar (26 mm thick) in sufficient quantity to meet the specification for export to overseas markets.
Keywords: WESTERN RED CEDAR; FUMIGATION; SACHETS; BIO-SECURITY