The best way of creating easy trees for the beginner, is to get some card and using brown, black, blue and red paint,
print the trunks and stems.
Add foliage and leaves by using crushed paper or small pieces of sponge.
The japanese have some great pencil shapes for creating the leaves and shapes of the different trees, and using some
of these strokes with paint helps the painting of realistic trees that are individual and different.
I also found students did well with printing using real leaves and bark for great effects. This stops the stereotyped
regular drawings and monotones that are often used to represent trees.
Paint the background, then paint the stems and trunks with card and print the foliage using leaves like Oak and gum that
give a great texture and have veins that print out too.
Be imaginative and creative in background effects. One does not need to paint stereotyped trees. In fact, get right away
from the set tree pattern and create something different.
One thing I stress is that trees are not the same...every tree has an individuality and uniqueness if it grows naturally
in nature..