Shout out to all the So Cal members here, I found a pretty close spot to where I live (OC area) to gather leaf litter and substrate for beetles. It's comprised of mainly oak, and it's in a national forest so no need to worry about pollution or chemicals. I got myself half a bucket full of substrate to see how it is, and there is a good mix of rotten wood chunks and leaf in it. We can plan a meet and greet day and also to grab some substrate! Let me know!