I have a Greenspire Linden in the front yard, planted approx. 10 years ago. For some reason, the top end has little or no leaves and the bottom end is doing beautifully. I have checked a couple of things: Looked for whitish powder and aphids on the leaves and found none. I have trimmed a couple of branches and pulled back the outer layer and the inner looks moist and clean. I am at a loss here. It was a perfect specimen last year with the exception of the Japanese Beetle problem later in the year, creating "skeleton" leaves after time. Picture included. Thank-you for your help!