By mid-October the oaks around Lake Parsippany let go all at once, and Troy Brook runs full of leaves down toward the low ground. Kearns Earthscapes handles lawn care through those streets — the cutting season first, then the long haul of fall cleanup. There is an art to a final mow: low enough to carry the lawn through the cold, even enough that the yard still looks composed under the first frost. Through summer it is the steady business of mowing and trimming, holding a clean line where the beds begin. A lawn that has been tended all season shows it most in November, once everything around it has gone bare.