Yeah the tree:land ratio of my back garden is highly in favour of the trees. Every autumn the entire area gets coated in a thick layer of sycamore leaves that can easily take a year to decompose even in a compost pile. I rake that shit into piles over my flowerbeds for the winter, then into the compost during the spring. I would mow them but it's the UK so it's rare to find an autumn day where the leaves aren't too wet and soggy.