Andy wants to know what is the difference between green and brown pressure treated wood, and why is the brown stuff only available in Western Canada?
The only difference is a brown stain added to imitate Cedar, a marketing necessity in the West where Cedar is inexpensive and popular for deck building. The problem is that Eastern wood won't accept this particular stain, only the Western growth stock takes the stain well.
While we are at it, you might also like to know that there is a brown End Cut treatment available to match the brown pressure treated wood.
More interesting yet is for everyone East and West to realise that there is a light green "colour matched" End Cut treatment that matches the normal green colour of pressure treated wood, rather than that bright green that looks so bad on the edge of the deck or the ends of the fence boards. Although the bright green will fade to the colour of the rest in about a year, starting off the right colour is much more satisfying when you finish building your deck.