Organize a field trip so students can paint trees from nature. Choose a location where trees stand out in their surroundings, especially an area which is sparsely populated by trees. The trees should be the centerpiece of the painting. The students can begin by concentrating on painting everything but the trees. This should be done with a very light use of color, which will allow for the trees to stand out more. The trees themselves should be depicted with a liberal use of both color and light and shade.
Arrange for students to paint a tree in isolation. This should be a tree which is not in full leaf or covered in blossom. Students should learn to appreciate the structure of a tree. A rough sketch of the trunk of the tree and its branches should precede the painting, and paint should then be applied over the sketch. The use of light and shade will be particularly important in this painting, and will reveal how a tree is richly textured.
Ask students to paint, from photographs, trees at dusk. Select photographs where trees are not too closely grouped together, as the outline of the individual trees should be emphasized. Trees at dusk will have a natural silhouette effect. Consider instructing the students to paint the trees but nothing else that may be visible in the photographs. The students should also closely study the shading of the trees. They should paint the shade colors that they see, and avoid using only black.
Have students paint trees in a triptych style. This will include painting the same tree three times, as it would appear in the winter, spring and fall. Students can work from a photograph, photographs or from their own imagination. The contrasts between the three trees will vividly illustrate the continually changing aspect of nature.