Jarrah
Also called: eucalyptus marginata
One page. Other spellings and regional names stay on this URL.
Jarrah (Eucalyptus marginata) is a heavy, hard Australian hardwood, also traded as Swan River mahogany, with strength to match its weight.
Appearance
Its heartwood is a rich brownish-red, marked with short dark flecks along the end grain, the surface left where wood is cut across its fibres, and with boat-shaped flecks on flatsawn faces, where a board is cut roughly parallel to the growth rings. Jarrah burr, a knotty, swirl-grained growth taken from the tree, is valued by woodturners for decorative pieces.
Working
Machining jarrah dulls tool edges to a moderate degree, and working it by hand is fairly hard going.
Uses, and jarrah beside karri
It has served for decking and underframing on piers, jetties and bridges, and for piles and fenders at docks and harbours. Karri, a related timber growing near jarrah, closely resembles it in character but comes out redder, denser, heavier and stronger across the grain, as Ellis (1908) put it, "somewhat redder, more dense, and heavy, and its lateral strength or cohesion greater than that of Jarrah." Even so, karri falls short of jarrah for underground and waterworks use. Jones (1920), referring to an unnamed related Australian timber, records it as "used almost indiscriminately with Jarrah for paving" and largely exported alongside it. Jones also describes an unnamed Tasmanian hardwood as "the most durable hardwood in Tasmania," preferred over both jarrah and karri for the piles driven ahead of the shield in tunnelling work.