I think a nick name for those are Choke Cherries. My dogs used to eat them off the bush when in season. I have tried them and when ripe the fruit is sweet but the skin is bitter. You could try calling Scott Eliason who is ( or was ) the USFS botanist. His number at the time was 909-382-2830. He may know something about how to germinate them. I tried growing from the small purple fruits of the Desert Olive some of them in our front yard. They never sprouted and I was told by Tom Eagan, who used to be a BLM botanist I think it was that there are special conditions related to the skin over the seed that had to happen before they would germinate. I once found a unique plant growing at Deep Creek with long colorful blooms. I sent Scott a picture of it and he identified the plant as being a Butterfly Bush, a non indigenous species for the area. I only ever in all my hikes at Deep Creek found one of those