Mike Oehler's engineering tables spec out the girders and beams to be Fir / Larch.
Can I use those engineering tables with other types of wood? Does it make a big difference what type of tree you use? Are hardwoods or softwoods better?
Oh sure, it's a tiny ad, but under the right circumstances, it gets bigger.
GAMCOD 2025: 200 square feet; Zero degrees F or colder; calories cheap and easy