Question
Jim, Would you have any idea why my Birch tree would loose all of it's leaves by the first week of September every year? I don't see any bugs on it, it has set the seed pods for next year and seems to be in a good location. A friend of mine has the same kind of tree and it still has all of it's leaves. Any suggestions?

Answer
Trees drop their leaves when the cells near the leaf "stem" shut down. This naturally is caused be a drop in temperature, shorter days and less water (which is the general conditions in the Fall). Also there are different genetic make up of trees even if they are the same species. I would think if the tree seem healthy it is just a difference in genetics and the tree will just show signs of Fall earlier than other trees of the same species. Another thing that could cause this leaf drop--here in my neighborhood we have an automatic watering system for the lanws and the common areas--we had a line break during the late summer and the maples dropped their leaves. The sudden losss of this "normal flow" of water shut the cells down and the tree "thought" it was Fall and drop leaves. If the tree is otherwise healthy, I lean toward the difference in genetic makeup.