I use ash as the center two lams in all my rockers. The back braces are designed to flex and the ash gives the flexibility and strength. Plus they make a nice contrast with walnut or cherry...not bad with this stuff either. Each lam is 0.090" thick for a total of almost 3/8" (0.360"), but I can put one on the floor and stand on the curve without having something bad happen. You can feel them flex when you rock.;-)