These Himalayan balsam plants were in an area of felled woodland next to the river Sgitheach, their branching pattern and large size share similarities with the shape of a Christmas tree! Most balsam plants growing in dense clumps tend to be tall and straight with the flowering structures located at the top. I believe this branching pattern may be caused when the plants get snapped off whilst growing but the root and bottom node remain allowing the plant to regenerate and regrow. These few larger branched plants were out in the open with plenty of space which may also benefit this growth structure. Any other suggestions???