Why Timber Grains Bend; Trees in Valleys and on Hills
Uneven branch growth twists the grain; draw from nature; foreshortened branches show leaves face-on
Under the head PARTE, a labelled chapter explains why timber grain is often not straight: when the second year's branches grow to one side rather than evenly above their predecessors, the vigor of the lower branch bends toward the higher, twisting the veins of the trunk; only equal growth keeps the grain straight and equidistant. Leonardo then exhorts the painter, who lacks such rules, to portray everything from nature and not despise study as profit-seekers do. Two further paragraphs observe that trees are larger and denser toward valley bottoms than on hill summits, that mountain tops stay grassier than their washed slopes, and that a branch coming toward the eye foreshortened shows its leaves nearly face-on. A pen sketch of a branch with radiating shoots sits in the middle of the page.
On this page
Why timber grain is not straight (c)
When each year's new branches grow to one side instead of squarely above the earlier ones, the vigor of the lower branch bends toward nourishing the higher, twisting the veins of the trunk. Only where the branchings grow with equality do the veins of the trunk stay straight and equidistant at every height.
Draw everything from nature
Leonardo turns to the reader: you, painter, who lack such rules, should be eager to portray each of your things from nature to escape the censure of the knowledgeable, and not despise study as the profit-seekers do.
Trees of the valleys and grassy mountaintops (d)
Toward the bottoms of valleys and along their branching folds the trees are larger and denser than toward the hill summits. The tops of the mountains are grassier than their slopes, because no flow of water runs there to wash them as it does on the slopes.
A foreshortened branch shows its leaves face-on (e)
If a tree's branch comes toward you foreshortened, its leaves show themselves to you face-on or nearly so. The passage breaks off as it turns to the case of the branch seen in its true, unforeshortened form.
Pen sketch of a branch with radiating shoots
A pen drawing in the center of the page shows an upright branch from which several twigs radiate in a star-like spray. It illustrates the uneven and even branch growth discussed in the timber-grain chapter above it.