I photographed this sycamore, Acer pseudoplatanus, last winter and have looked at the perfect sycamore shape on screen and on the farm, regularly through the summer, and found myself pondering about how trees become tree-shaped and how or even why a sycamore is sycamore-shaped whereas an English oak, Quecus robur tends to be oak-shaped. I know there’s loads of variation within a species – caused by wind, people, grazing animals and so on; but individuals that escape such attention do often grown into the shape required of members of the species. That’s certainly true of this one that stands near the River Hitt. It was coppiced quite a few years again and although now multi-stemmed as a result, it’s most definitely sycamore-shaped. That’s amazing and wonderful.
Leaf growth in spring leads development of supporting twigs, so the answer must be dictated by the pattern of leaves growing to maximise collection of light. It’s tempting to imagine a plan hatched by the tree during long winter months, to map out the position in three dimensions, of every leaf by the end of April. However, I assume each leaf develops as a result of bud location which in turn is dictated by each species’ bud location blue print – sycamores and ash in opposite pairs, oaks in unpaired clusters at the twig tip.
Every tree species and probably every woody species produces leaves from the tip of the shoot; certainly that’s true of the tree species I deal with most. Given that, and given that those leaves that find themselves at the tip are in a position to spread themselves flat to absorb maximum rays, shouldn’t that make all trees or even all plants the same shape? Obviously not.