I have a group of black pine in the northwest corner of my yard that I planted ten years ago for a windbreak. They are too close together for much to grow in between, but musk strawberries are really thriving around the edges. I cut one pine to improve visisbility while backing out of the driveway and found a nice surprise, two seedling black raspberries, around a year old, I'd guess. They couldn't have had much light, so probably stunted. I assume the seeds passed through a bird since my raspberry planting is 30 yards away and on the other side of the house. I've had them about 12 years. I've never noticed a seedling before. Maybe it's not that unusual? It'll be interesting to see if they're much different than the parents.