Learn from other artists whose renderings of trees you love
Learn from other artists whose renderings of trees you love. Mark me down as a Wolf Kahn follower. His forests of trees are gesture rich, and pure blocks of color are woven into the whole. I did the drawing posted here directly from a WK as a study to try to "get" more of what his methods are.
Evening Pines, by Deborah Paris, gives a similar treatment of trees at a forest's edge. Atmosphere prevails, and I have a feeling that I am standing among the liquid air of 100 degree Georgia humidity at dusk. Her Tonalist style involves a limited palette and a narrow range of values. I can't help but feel completely present in these woods when I am looking at Evening Pines.
Albert Handell'sWoods Interior expresses the abstract qualities of just tree trunks. His tree trunks have more texture with less apparent effort than almost any artist I know of.
All of the artists I've mentioned here take a very different approach to trees, and your tree style will become a signature of your own work.