Now that's how you paint a tree. It gets a lot harder when you're older. Especially when they're all bunched up and you're trying to paint them in changing light. You can't see where one ends and the next begins, or where the branches start and finish. The trunk is in there somewhere, and you could see it yesterday when the light was different. But you can also see the outline of the tree behind through the tree you're trying to paint, and that's not helping at all...
So you have to get organized when you're drawing or painting something that insists on being undrawable. Painting trees en masse is a little like painting clouds, in that both move about and are made up of deceptive forms which change appearance with the light.
'But trees just stand there,' you say. Well, yeah, but their forms are hard to read, in that while a mass of foliage looks like a solid some of the time, it's really a collection of twigs and leaves. And because of this, as the sun moves, or clouds cover it, different aspects of various trees appear and disappear like stage flats lit by madmen. Branches pop in and out of sight. Foliage is light, then dark. And it moves with the wind. So you have to simplify, and make what is ambiguous, plain. Painting demands that we pick and choose from what we can see, and make all our selections work together in one convincing whole.
I often start with the trunk, then try to lay in the branches and the outline all at the same time. If you get the outline, that's half the job of making your tree look convincing done. The outline can usually identify the species, which at least tells the viewer you actually looked at a real tree. Incidentally, learning a little about the species of tree you're likely to encounter can help you draw and paint them well.
Judicious placement of sky holes comes last - probably fewer than there are in real life, unless you want your tree to resemble a lace doilie. Remember that verisimilitude matters, but making a good painting matters more. There comes a point when a painting has enough facts in it, and you have to start thinking of it as a performer thinks of a music score. Getting the notes right counts, but not as much as making music.
