As Frank Gardiner pointed out in his comments yesterday, the trees have ‘holes,’ too. They are important.
The lesson here is to study your trees carefully. The effort pays off in a great way; you have a memory of the trees and how they are constructed so that you can improvise on your canvas and get the idea across to the viewer. Look at a series of maple trees, or elms, or some of the pine varieties. Each has a distinctive shape.
The last photo here is of a series of cottonwoods near some farm buildings and a sketch of some different variations on the fan theme of a line of cottonwoods. Note, these trees often have multiple trunks, too. Interesting.
You may not be interested in cottonwoods. However, in building art about a subject, the more you can modify and create changes in the reality, yet retain the character of it, the more your own style comes to life. It is important to be able to improvise! That can only happen when you keep the core truth about the subject . . . .Jazz is the same exact thing: Improvisation around a melody. We still hear the melody, but the stylization is mezmorizing.