Hi, I am trying to source some floorboards to replace some rotten ones, but am unsure what wood they are. I was thinking pine but they don't have many knots. Any thoughts?
Depending on the age and class of the house they may be pine, your pic is, ummm, a little obscure.
In the old days wood was better quality. The pine of C19 was slow-grown, immeasurably better than the rubbish one generally encounters now.
Perhaps try another pic.
How old is the house, what type of house and in what room?
Almost certainly slow growing Baltic pine. Still available but harder to get. Wall to wall fitted carpets are a modern creation and in period houses a darker border is often visible where a central rug finished and the remainder was stained to look like more expensive hard wood,