Douglas Fir Stair Treads
Douglas Fir has a light color to it, most of the time. You can find different grades that range from a lighter shade of white, to a dark reddish brown. Douglas fir is also used on the West Coast of the United States as construction standard lumber. In other words it's used to frame homes and buildings.
Douglas fir makes an excellent stair tread and is used
through out the United States, on interior and exterior staircases. I
don't recommend Douglas Fir for an Interior stair tread, that's not
going to be covered with carpeting or other stair tread coverings. It's
a softer hardwood and will scratch easily.
Gluing = Excellent, Douglas Fir is a great wood to glue together, as long as you use a high quality adhesive, you shouldn't have any problems.
Sanding = Great, Douglas Fir is an easy wood to sand, but could be a little too easy, sometimes. If you sand it too much, you will raise the grains, creating a wavy surface that might not finish well. It actually creates a nice looking stairway, when it's sandblasted, because the grains in the lumber will actually stand out.
Staining = Excellent, this is a fantastic wood to stain and will usually suck it up, like a sponge. Even though it's easier to stain, it's going to need more maintenance than some of the tougher woods.
Nailing = Excellent, since Douglas Fir is one of the softer hardwoods, it's going to be easier to nail or screw. However it can split like other hardwoods, if the lumber is too dry or your nailing near the edge of the board.
Wear And Tear = Moderate, even though I recommend Douglas Fir, it's going to wear a little faster than some of the other lumber. You're not going to find too many finish carpenters using this wood, because it rarely produces a spectacular stairway.
Janka Hardness Scale = 660 This is definitely one of the softer hardwoods and is going to wear faster, than almost all of the others.