Outdoor Garden Planters Whats The Best Timber For Large Planter Boxes-Outdoor? Australia?

Whats the best timber for large planter boxes-Outdoor? Australia? - outdoor garden planters

I have a few planters and walls to keep in my garden. What is the best wood to use? I heard that the treated wood pine, is not good for the soil. If not, what should I do for the wood to make available to the open? I would add a stain to it, such as oil and a little busy to make it dark, but I must add a little below this layer to make it resistant to insects and rain, etc. .. I am in Australia if it makes a difference in the type of wood, I can.