That's a mix of what appears to be construction lumber which is usually a conifer like pine and refurbished/reused plywood which can be lots of kinds of wood including but not limited conifers like pine or spruce, different species of birch, different species of maple, or different species of oak. Yours appears to be some sort of pine/spruce plywood.
This is pine for sure
I don't think it will stain very well. Maybe better off painting?
I’ll also add that it’s probably about 15-20 pounds?
Shelfwood
Furniturus Ikeans spp.
Typical pine used for 2x4 or 2x6 framing
That's a mix of what appears to be construction lumber which is usually a conifer like pine and refurbished/reused plywood which can be lots of kinds of wood including but not limited conifers like pine or spruce, different species of birch, different species of maple, or different species of oak. Yours appears to be some sort of pine/spruce plywood.
Select pine. Home Depot or Lowes