Hi Snatchblock;

I agree with Don to use what was used locally, if you are using a traditional design in the same way they were built before. Any joints designed to be in continuous tension such as a tie beam into a post should be the strongest wood you have. You can use different species pegs in different joints.

We have powder post beetles who like our red oak more than our eastern white pine so I have seen buildings with timbers in good condition but the pegs are weakened from insect damage.

Tim Beal (Hi Tim) says spruce pegs are common in his neighborhood but hardwood pegs, particularly our species of red oak, are the most common wood for pegs in the U.S. as far as I have seen. I have seen red maple and black locust is another good choice. I have seen spruce pegs in a spruce frame.

If you can accurately draw bore 1/8", your joints will pull together just fine and the peg will not shrink that much.

Good luck;
Jim