Using less desirable woods in outdoor construction

I've got 3 acres of woods, some of it overgrown too close to the garden and the house. Some of it can be used for firewood, but we have a need for various types of outdoor construction. Some of the things needing to be built are: sheds, covered structures, fencing, terracing and more.  Unfortunately most of the wood has low rot and insect resistance, it's California Bay and Red Alder.

Is it worth even attempting to use some of it for interior framing and rafters of open and closed structures, esp the Red Alder? Or should I not even bother?

In my experience, even rot-prone timbers will last a surprising amount of time. I wouldn't want to use them for anything structural but for simple structures - providing the time/energy investment in using them isn't too high, it's always worth considering using what you have.

Something else to consider is whether you can use the wood in protected environments. Floorboards, countertops, interior cladding - anything away from the weather. Dry wood is unlikely to rot and is generally much less appealing to insects too.