How to test see if wood has been tanalised?

1. Look for the green color. Tanalised wood is often treated with a copper-based preservative that gives it a green color. However, not all tanalised wood is green, so this is not a foolproof method.

2. Check for the stamping. Tanalised wood is usually stamped with the manufacturer's name and the words "tanalised" or "pressure treated." This is the most reliable way to tell if wood has been tanalised.

3. Test the wood with a metal detector. Tanalised wood contains metal salts, which can be detected with a metal detector. This method is not as reliable as the other two methods, but it can be useful if you don't have access to the manufacturer's stamp.

If you are still not sure whether wood has been tanalised, you can contact the manufacturer or a professional woodworker.