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Clicking any heading in the main data area (at right) will scroll the page back to this top position. Use the following links to jump to the associated section in the main data. Blunting Effect Boring Carving Comments Common Names Common Uses Countries of Distribution Cutting Resistance Distribution Overview Drying Defects Ease of Drying Environmental Profile Family Name Gluing Grain Heartwood Color Kiln Schedules Luster Mortising Moulding Movement in Service Nailing Natural Durability Numerical Data Odor Planing Polishing Product Sources References Regions of Distribution Resistance to Impregnation Response to Hand Tools Routing & Recessing Sapwood Color Scientific Name Screwing Staining Strength Properties Texture Trade Name Tree Size Turning Varnishing Scientific Name Acacia koa Trade Name Koa Family Name Leguminosae Common Names Koa Regions of Distribution Oceania and S.E. Asia Countries of Distribution  [VIEW MAP] Hawaii [US] Common Uses Bent Parts, Boat building, Building materials, Canoes, Core Stock, Decorative veneer, Drum sticks, Excelsior, Figured veneer, Gunstocks, Interior construction, Joinery, Lifeboats, Musical instruments , Novelties, Organ pipes, Paneling , Piano keys, Pianos , Plain veneer, Rifle stock, Shipbuilding, Sounding boards, Sporting Goods, Veneer, Violin bows, Violin, Wainscotting, Xylophones Environmental Profile Rare Status has not been officially assessed Appears to be rare in much of its natural habitat Distribution Overview Found exclusively on the Hawaiian Islands, Koa trees reach a height of 100 feet with a diameter of 4 feet. It grows at most elevations on the islands, but grows best in areas of heavy rainfall form 3,000 to 6,000 feet. It is the most conspicuous tree growing between the low, open dry forest and the wet ohia forest, and is generally quite adaptable to a variety of climates. Heartwood Color Brown Red Yellow Purple White Highly variable Tan Reddish brown Pale blond Golden brown with a reddish cast Color varies considerably Chocolate The wood yellows quickly in sunlight, which adversely affects its exterior performance Sapwood Color Brown Red Pale brown Clearly differentiated from the heartwood Grain Figure Wavy Closed Interlocked Fiddleback (figure) Other (figure) Growth rings (figure) With distinct light and dark bands Wavy Moderately to severely interlocked Figure shows a rainbow pattern Fiddleback figure Curly Attractive patterns Texture Coarse Medium Medium coarse to coarse Luster High High Natural Durability Perishable Non-resistant to termites Non-durable Very little natural resistance Highly susceptible to attack by subterr. and dry wood termites Odor No specific smell or taste Kiln Schedules Schedule F (4/4) United Kingdom 6 - D4 (4/4); T3 - D3 (8/4) US Drying Defects Checking Surface checks Problems generally only with thicker stock Ease of Drying Reconditioning Treatement Fairly Easy Little degrade Little or no degrade Easy Tree Size Tree height is 20-30 m Trunk diameter is 100-150 cm The trees are very hardy and can survive under almost any environmental condition Product Sources Supplies of Koa are available on the U.S. market in the form of lumber and veneers. Prices are in the high range. Comments Excellent for musical instruments because of its high resonant properties. Hawaiian ukeleles are made exclusively from koa wood. Trees that grow at high exposed areas produce the best figured wood, and the veneer form of Koa is highly valued for fine furniture because of its fiddleback figure and high finish it takes. Koa wood is similar to Black walnut (Juglans nigra) Blunting Effect Moderate Medium effect Boring Fair to good results Fairly easy to very easy Carving Fair to Good Results Fairly Easy to Very Easy Cutting Resistance Fairly Difficult to Very Difficult to saw Difficult to saw Interlocked grain. Keep tools sharp to prevent tearouts Gluing Poor to Very Poor Results Gluing properties are variable, but they are generally poor Mortising Fair to Good Results Fairly Easy to Very Easy Moulding Fair to Good Results Fairly Easy to Very Easy Movement in Service Excellent Stability - Small Movement Fair to Good Stability - Medium Movement Stable Nailing Fair to Good Results Fairly Easy to Very Easy Satisfactory nailing properties Planing Fairly Easy to Very Easy Fair to Good Results End-grain material requires very sharp cutting edges Easy to plane Wood containing curly grain may require a cutting angle of 20 degrees for best results Resistance to Impregnation Resistant sapwood Resistant heartwood Very resistant Response to Hand Tools Responds Readily Routing & Recessing Fair to Good Results Fairly Easy to Very Easy Screwing Fair to Good Results Fairly Easy to Very Easy Good screw holding properties Turning Fair to Good Results Fairly Easy to Very Easy Polishing Fair to Good Results Fairly Easy to Very Easy Very Good to Excellent Results Excellent results Staining Fairly Easy to Very Easy Fair to Good Results Very Good to Excellent Results Stains very well Varnishing Fairly Easy to Very Easy Fair to Good Results Very Good to Excellent Results Very well Strength Properties Weight = high Density = high Compression strength (parallel to grain) = high Bending strength (MOR) = high Numerical Data Item Green Dry English Bending Strength 7389 11226 psi Density 37 lbs/ft3 Maximum Crushing Strength 3695 6537 psi Shearing Strength 1662 psi Stiffness 1293 1520 1000 psi Specific Gravity 0.54 Weight 39 32. lbs/ft3 Item Green Dry Metric Bending Strength 519 789 kg/cm2 Density 592 kg/m3 Maximum Crushing Strength 259 459 kg/cm2 Shearing Strength 116 kg/cm2 Stiffness 90 106 1000 kg/cm2 Specific Gravity 0.54 References Boone, R.S., C.J. Kozlik, P.J. Bois and E.M. Wengert. 1988. Dry Kiln Schedules for Commercial Woods: Temperate and Tropical. USDA, Forest Service, Forest Products Laboratory, General Technical Report FPL-GTR-57, Madison, Wisconsin. Constantine, Jr. A.J. 1975. Know your Woods: A Complete Guide to Trees, Woods, and Veneers. Revised Edition. Revised by Harry J. Hobbs. Charles Scribner and Sons, New York. Imported Wood Purchasing Guide: A Comprehensive Purchasing Reference for Imported Woods. 1992. 20th Edition. International Wood Trade Publication, Inc. 1235 Sycamore View, Box 34908, Memphis Tennessee. Kaiser, J. 1990. Wood of the Month: Koa - The Wood from the Hawaiian Islands. Wood & Wood Products, January 1990, Page 48. Keating, W.G., Bolza, E.,1982,Characteristics properties and uses of timbers. South East Asia, Northern,Australia and the Pacific,C.S.I.R.O. Div. Chemical Technology,Inkata Press,1 Kline, M. 1982. Acacia koa - Koa. In A Guide to Useful Woods of the World. Flynn Jr., J.H., Editor. King Philip Publishing Co., Portland, Maine. 1994. Page 12. Lincoln, W.A. 1986. World Woods in Color. Linden Publishing Co. Inc., Fresno, California.