Question

I have 28 years background as a general contractor in the northern bay area and San Francisco area. I hired some guys out of Lake tahoe. I have always assembled exterior decks made from pressure treated wood and/ or redwood framing and have used the same and some cedar for any framing that is exposed to the weather. I walked onto the jobsite today and found that they had assembled twin decks [that are exposed to the weather] framed in doug fir. When I asked why, they told me that, in Lake tahoe at least, no one uses presssure treated framing and underpinnings. They use only Doug fir. I was under the impression that the UBC specifically calls for any framing members exposed to the elements to be pressure treated, redwood or cedar. I have not been able to find my UBC and have no way to look it up. Can anyone help me find out the accuracy of my impressions. Thanks Jerry