I have found that i can change the material on an existing partical system tree to use my own sprite. BUT some times the control "Puck" is not near the image. any ideas?
It seems to help croping the images as close as possible but sitll not perfect.
Any other pointers on simple trees. not getting into the 3-d create a tree- too many questions.
I would create a very thin disc (a cylinder with 5 mm height) - set the transparency to black 50% - Copy the sprite (single element particle system) and paste it onto the disc - now use the disc as the parent object. If you get tricky you can apply a leaf texture to the cyclinder to make the shadow look more realistic.