All trees seen against the sun are dark towards the middle and this
shadow will be of the shape of the tree when apart from others.

The shadows cast by trees on which the sun shines are as dark as
those of the middle of the tree.

The shadow cast by a tree is never less than the mass of the tree
but becomes taller in proportion as the spot on which it falls,
slopes towards the centre of the world.

The shadow will be densest in the middle of the tree when the tree
has the fewest branches.

[Footnote: The three diagrams which accompany this text are placed,
in the original, before lines 7-11. At the spots marked _B_ Leonardo
wrote _Albero_ (tree). At _A_ is the word _Sole_ (sun), at _C Monte_
(mountain) at _D piano_ (plain) and at _E cima_ (summit).]

Every branch participates of the central shadow of every other
branch and consequently [of that] of the whole tree.

The form of any shadow from a branch or tree is circumscribed by the
light which falls from the side whence the light comes; and this
illumination gives the shape of the shadow, and this may be of the
distance of a mile from the side where the sun is.

If it happens that a cloud should anywhere overshadow some part of a
hill the [shadow of the] trees there will change less than in the
plains; for these trees on the hills have their branches thicker,
because they grow less high each year than in the plains. Therefore
as these branches are dark by nature and being so full of shade, the
shadow of the clouds cannot darken them any more; but the open
spaces between the trees, which have no strong shadow change very
much in tone and particularly those which vary from green; that is
ploughed lands or fallen mountains or barren lands or rocks. Where
the trees are against the atmosphere they appear all the same
colour--if indeed they are not very close together or very thickly
covered with leaves like the fir and similar trees. When you see the
trees from the side from which the sun lights them, you will see
them almost all of the same tone, and the shadows in them will be
hidden by the leaves in the light, which come between your eye and
those shadows.

TREES AT A SHORT DISTANCE.

[Footnote 29: The heading _alberi vicini_ (trees at a short
distance) is in the original manuscript written in the margin.] When
the trees are situated between the sun and the eye, beyond the
shadow which spreads from their centre, the green of their leaves
will be seen transparent; but this transparency will be broken in
many places by the leaves and boughs in shadow which will come
between you and them, or, in their upper portions, they will be
accompanied by many lights reflected from the leaves.