Compression wood (CW) forms on the underside of tilted stems of coniferous gymnosperms and opposite wood (OW) on the upperside. The tracheid walls of these wood types differ structurally and chemically. | Tracheid cell-wall structures and locations of 1 4 -β-D-galactans and 1 3 -β-Dglucans in compression woods of radiata pine Pinus radiata D. Don