On the streets around the Forsyth Nature Center, a mower works like a clock — Saturday morning, somebody's small square of Kingston getting its trim. McDermott Landscaping keeps that rhythm going up and down Lucas Avenue and the side streets off it: mowing, string trimming, edging along the walk, and the clippings carried off. City lots here are modest and hemmed in by fences, hedges and old stone curbing, so the work is done mostly on foot, one careful pass at a time. By late fall the job becomes leaves, oak and maple ankle-deep, raked back down to green. Small yards, done right, change the way a whole block looks.