Tree Dictionary: J-L

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JARRAH (Eucalyptus marginata)

Other Names: Eucalyptus.
Type: Hardwood
Range: Grows in south-western Australia.
Appearance: Typically straight grained but often interlocked and wavy. Moderately coarse, even texture. Rich dark reddish brown heartwood, often with gum veins and boat-shaped flecks. Paler reddish brown sapwood.
Physical Properties: Heavy, hard, strong (particularly crushing strength), and stiff with moderate dimensional stability in service. Highly decay resistant heartwood.
Working Properties: Fairly difficult to work due to hardness and density. Reduced cutting angle recommended for planing. Turns well. Pre-drilling required for screwing and nailing. Glues and finishes well.
Uses: Used extensively for construction in Australia, particularly for marine applications such as bridges, dock pilings, wharfs, and ship building. Also used for flooring, cross-ties, shingles, siding, trim, rafters, joists, furniture, interior joinery, chemical vats, and decorative veneers. Valued for striking tool handles.
Note: More jarrah is harvested than any other commercial Australian timber. It is more appropriate than Karri for marine applications but it’s not quite as heavy or as strong.

LARCH, EUROPEAN (Larix decidua)

Other Names: European larch, common larch, lark, and tamarack.
Type: Softwood
Range: Grows in Europe and southeast Asia.
Appearance: Typically straight, but sometimes spiral grained with a fine, uniform texture. Pale red to brick red heartwood and narrow, pale yellow sapwood. Growth rings well defined.
Physical Properties: Moderately heavy and hard with moderate stiffness, bending strength, crushing strength, and decay resistance. Very stable in service.
Working Properties: Works fairly easily with hand or machine tools but knots may blunt cutting edges and cause chip-out. Glues satisfactorily. Pre-drilling required for screwing or nailing. Accepts paints, stains, and finishes well.
Uses: Used primarily for utility poles, pilings, pit props, and stakes. Also used for boat planking, flooring, bridge construction, railway sleepers, exterior joinery, clogs, shingles, siding, trim, stair rails, plywood, paneling, and decorative veneers.


LARCH, WESTERN (Larix occidentalis)

Other Names: Larch, tamarack, western tamarack, hackmatack, Montana larch, and mountain larch.
Type: Softwood
Range: Grows in British Columbia and northwestern United States. Most important Larch timber species.
Appearance: Straight grained with a coarse texture and oily appearance. Reddish brown heartwood and yellowish white sapwood.
Physical Properties: Moderately heavy and hard with high stiffness, bending and crushing strength, and moderate decay resistance. One of the harder, stronger, and heavier softwoods. Stable in service.
Working Properties: Works fairly well although stringy grain can cause problems when planing. Turns, routs, and bores well. Glues satisfactorily. Holds nails and screws well but pre-drilling recommended to prevent splitting. Primer recommended for paints and other finishes.
Uses: Used for construction lumber, interior finish, sash, flooring, doors, boxes, crates, pallets, casks, veneer, plywood, and glue-laminated beams. Properties are similar to those of Douglas-fir and is often marketed and sold as “Doug fir-Larch”.


LOCUST, BLACK (Robinia pseudoacacia)

Other Names: Yellow locust, acacia, and false acacia.
Type: Hardwood
Range: Grows in United States and southern Canada.
Appearance: Straight, pronounced grain with a coarse, uneven texture. Greenish yellow to dark brown heartwood and narrow, yellowish sapwood.
Physical Properties: Heavy, moderately hard, with high bending and crushing strength, stiffness, shock resistance, and decay resistance.
Working Properties: Machines well but is difficult to work with hand tools. Tends to dull cutting edges. Glues satisfactorily, takes a high polish, finishes easily, and is stable in use. Screwing and nailing can be difficult.
Uses: Used for fenceposts, rails, stakes, crates and boxes, mine equipment, insulator pins, ship treenails, tool handles, woodenware, novelties, outdoor furniture.