From the book A Guide to Nature in Winter by Donald Stokes:
“Trees are plants that have evolved woody stems so that their leaves will be supported in the air, thus avoiding the competition for sunlight at ground level. As with all green plants, their first priority must be to place their leaves in sunlight, for the sun is the primal source of their energy. This striving to arrange leaves in light is most clearly shown in the winter trees. Here in the outline of their bare branches hundreds of solutions are revealed, each species a distinct linear sculpture created jointly by the forces of light and life…”
Max Harrick Shenk, writer 