What size of tree do you want to plant? If you want 3 yr seedlings try
www.treetime.ca. They have a good selection and I think free shipping if you spend a certain amount of money. If you are looking for very hardy trees try Bow Point Nursery.
If you like the tower type of tree then try the Swedish aspen which in my opinion is better then the tower popular. I have been told they have less aggressive roots but I'm not sure if they are chinook proof.