That area had lots going for it, like rivers filled with salmon to eat. The coast gave them tons of fish and shellfish to eat. They also hunted whales and birds for food. The forests had game animals they could hunt, like moose, goats, sheep. Other animals such as foxes provided fur to keep warm. The Northwest forests had lots of trees in that area like giant Douglas fir, cedar, and spruce for building materials, clothing, bedding, canoes, tools, firewood and much more.
Having these things was very important at that time. It is not like today where you could just go to Home Deport for building supplies, or to your local grocery store for food. You had to find all that on your own.