It looked dark wood for pine so maybe redwood - I will ask the man next time I am there- other projects to finish before I start that4 inch thick seems a bit chunky. 2 or 3 should be fine . 12 by 2 will be spruce like scaffold boards. 9 by 2 redwood would be a lot better. especially for hand planing. quebec yellow pine is soft but lovely and stable and light big knots though.