Kinda reminds me of aged barn wood Sassafras. this link shows it as a lighter colored wood but the sassafras that I have had was much darker than the ones in the link:
https://www.wood-database.com/sassafras/
The end grain looks the same as yours.
Aged Black Ash is my second choice. One thing that should be noted is that it sure looks aged or thermally modified. If it were purely aged out in the weather, it would be grey. but if it were under other boards for 50 years, it could maintain its basic color while aging.
Mulberry is a wood that looks like teak in color when cut and finished, but if aged before finishing, it turns almost chocolate brown and looks similar to walnut.
I just remembered what that COLOR wood (that you posted) looks like:
1. the boards of the inside of the ceiling of an old house. The heat over the years will do that to boards (our attic has pine boards that color);
2. the boards of a house wall (on the outside wall) that has had tar paper over it before siding or other siding placed. I have seen wood that color from houses being torn down. The years of summer heat and tar paper (weather sheeting) penetrated into the wood.
The color changes caused from 1 or 2 above makes the specific wood identification more difficult in pictures, unless someone has worked with it within the region that you live.