We recently bought a house in southern California that has a Norfolk pine with 3 trunks. The main trunk is 18-20 feet, another is about 15 feet and another is sort of wrapped around the main trunk at the base and is about 13 or 14 feet high and growing at a 60-70 degree angle to the ground. I've read that it is best to prune off multiple trunks. Is that true and should it be done for a tree this size? I am somewhat concerned that the shortest trunk will not be stable given the angle is it growing at. Ideally, I would like this tree to grow to 50 feet or so to provide shade on the west side of our house. If I allow it to continue to grow with multiple trunks, will that limit the overall heigth?