It can be very difficult sometimes to shake off childhood habits and study them closer. When at school, a child would draw a green lollipop an a brown stick and teacher would pat the child on the head and heap on the praise. What happens? This memory sticks in the childs head and they don't move on from that position when the next tree has to be drawn. Ask almost any adult to draw a tree and see what you get. (That doesn't mean you dear reader).
I still suffer from that today. I think I know what it should look like and just keep painting without looking up. I have to remind myself that this is wrong and I should really be painting as though I had never seen a tree before and painting it for the first time. Just wish I could listen to my own advice.