Redwood Everywhere... even the framing?!

I was working on the laundry closet and I saw a piece of redwood bark fall off a framing member. Wait a second! Framing is supposed to be Doug Fir! I already knew that the ceiling beams and sheathing, doors, trim, cabinets and flooring are made out of redwood. But the framing too? That would be an unusual upgrade! I know redwood framing was done in redwood rich places like Eureka in the 19th and early 20th centuries, but this much redwood in Oakland is odd.

Redwood burl front door pull. The rest of the door is... redwood also.

Fancy old redwood fencing boards next to redwood grape stake fence next to redwood retaining wall

If there is redwood framing, that would explain how the house held up so well without having a new roof since 1960 since redwood has natural anti-fungal properties (which is why it is used as an "exterior wood" like cedar).

EDIT:

Upon closer inspection, it appears the redwood used for framing here is a "rough hewn" type which has an undulating angled mark on it that might be caused by an old saw blade

Below you can see this bit of door trim is redwood, while the member to its left is flat.

I'll remember this distinction to see if it gives me some insight. For example, it would be interesting if the original house was framed in redwood, while the rest of the house was not. I'll add it here if I find more redwood in any more interesting spots...