How Tree Branches Grow, Bend and Rise
Branches in the fork, spiral twigs, and why the tallest boughs stay near the centre
Three red-chalk notes on the growth of branches accompany light sketches of a tree, a single branch and a cluster of twigs at the right of the leaf. Leonardo observes that plants which fork near the ground rarely put shoots into the space between the two limbs, and any that do stay small because the limbs shade one another. He notes that many bends in a branch lack the six spiral twigs that should surround them, the twigs having failed in youth, and that the principal, tallest branches always grow nearest the plant's central axis.
On this page
Shoots in the fork rarely thrive
Plants that divide near the ground rarely put out branches into the space between the two limbs. If one is born there it has a short life and little size, because of the shadows the limbs cast on one another.
Bends left bare of their six spiral twigs
Many of a branch's bends lack any of the 6 little twigs that should surround them spirally, because those twigs were wanting in the branch's youth. Death then followed in the more necessary parts, wholly abandoning such humps.
The tallest boughs stay nearest the trunk's centre
The more principal branches of trees, those that rise the highest, are always nearer to the middle of the plant than any of their other brothers or sons. Leonardo frames the boughs as a family, the leaders keeping to the central axis.