Every winter we lose a portion of leaves off the lower branches of our holly trees which are replaced (90%) by summer. Over the years this has resulted in bare branches on the lower parts of the trees. The leaves have various sizes of dusky brown spots on them and are otherwise normal, many almost appear normal. Aside from the tree damage it is a nuisance in that we have to (we are told) dispose of all the leaves rather than compost. We are against the use of any chemicals to solve this problem. Any suggestuions?