hardi plank is the way to go
As for your shade trees, I put two impact sprinklers on the roof of my house during fire season and they take care of my shade trees. well I hope they do, as I haven't had the opportunity to load test this contraption.
Northern California is great but can be stressful during fire season

Hi Earl,

Ain't that the truth. In fact, it can get downright surreal. There was a fire on a ridge a few miles south of us a few years ago. We got out lawn chairs to watch to be sure it stayed going west to east and not north toward us. It was wild watching the insane four engine water bomber pilots come in at a 45 degree glide path and fly down toward the valley. Those people have more guts than I'll ever have. At the end of their run, they had to do a quick pull-up or crash into the ridge on the other side of the valley.

There have been lots of other fires over the years but you never get used to it.

Todd