By late October the maples along the North Beverly streets have dropped enough to bury a lawn outright, and the light coming off Wenham Lake turns thin and silver. K & B Landscaping & Tree Services works that season down to the last curbside pile, raking and clearing the leaves, taking the grass to its final height, and edging the walks before the ground stiffens. Autumn is when a lawn either gets set up for spring or gets smothered, and the difference is entirely a matter of who showed up. Through the growing months it is the steady rhythm instead: mow, trim, edge, blow off, move on. The best sight of the whole year is a bare green yard in November with the leaves gone and the lines still holding.