European redwood is the UK trade name for Scots pine (Pinus sylvestris) when it’s sold into joinery and construction markets. It’s valued because it gives you a more characterful, more durable pine than whitewood: warm reddish-brown heartwood, pale sapwood, and a familiar resinous “pine” smell in the workshop.
It machines easily, fixes well and takes paint exceptionally well, which is why it’s a standard choice for window components, doors, mouldings and general joinery. Like most pines, knots and resin pockets are part of the package — they’re manageable, but they do influence finishing (knot sealing/isolating primers) and sometimes gluing on pitchy areas.
Durability depends heavily on what part of the wood you’re using: heartwood is moderately durable for a softwood, while sapwood is perishable but treats very well. That combination is exactly why redwood remains a workhorse in the UK: it can be used untreated for many interior roles, or treated and detailed correctly for long-lived exterior work.