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Bur oak

Quercus macrocarpa

U.S. hardwood · Oaks · United States

Bur oak measures 1,370 lbf on the Janka scale, 6% harder than northern red oak.

  • Only five of the 155 woods bend more easily.
  • On the Janka scale its nearest neighbours are white oak at 1,360 lbf and scarlet oak at 1,400 lbf.

Compare bur oak

U.S. hardwoodsU.S. softwoodsImported woodsNorthern red oak

Bur oak · 1,370 lbfCeibaEastern white pineBlack cherrySugar mapleShagbark hickoryIpe01,0002,0003,0004,000 lbf← softerharder →Ceiba, 240 lbfNorthern white-cedar, 320 lbfAtlantic white-cedar, 350 lbfBlack cottonwood, 350 lbfQuaking aspen, 350 lbfSubalpine fir, 350 lbfWestern redcedar, 350 lbfBalsam fir, 380 lbfCuangare, 380 lbfEastern white pine, 380 lbfOkoume, 380 lbfSugar pine, 380 lbfEngelmann spruce, 390 lbfAmerican basswood, 410 lbfNoble fir, 410 lbfRedwood (young-growth), 420 lbfWestern white pine, 420 lbfEastern cottonwood, 430 lbfObeche, 430 lbfPacific silver fir, 430 lbfLight red meranti, 460 lbfPonderosa pine, 460 lbfIncense-cedar, 470 lbfLodgepole pine, 480 lbfRedwood (old-growth), 480 lbfWhite fir, 480 lbfButternut, 490 lbfGrand fir, 490 lbfLimba, 490 lbfCalifornia red fir, 500 lbfEastern hemlock, 500 lbfBanak, 510 lbfSitka spruce, 510 lbfBlack spruce, 530 lbfAmerican chestnut, 540 lbfWestern hemlock, 540 lbfYellow-poplar, 540 lbfHura, 550 lbfRed pine, 560 lbfJack pine, 570 lbfYellow-cedar, 580 lbfRed alder, 590 lbfTamarack, 590 lbfDouglas-fir (Interior North), 600 lbfSpanish-cedar, 600 lbfIlomba, 610 lbfCativo, 630 lbfPort-Orford-cedar, 630 lbfDeterma, 660 lbfDouglas-fir (Interior West), 660 lbfPrimavera, 660 lbfMountain hemlock, 680 lbfLoblolly pine, 690 lbfShortleaf pine, 690 lbfCucumbertree, 700 lbfSilver maple, 700 lbfDouglas-fir (Coast), 710 lbfVirginia pine, 740 lbfAmerican sycamore, 770 lbfYellow meranti, 770 lbfDark red meranti, 780 lbfParana-pine, 780 lbfMahogany, 800 lbfBlack tupelo, 810 lbfAfrican mahogany, 830 lbfAmerican elm, 830 lbfWestern larch, 830 lbfBigleaf maple, 850 lbfBlack ash, 850 lbfSweetgum, 850 lbfSlippery elm, 860 lbfLongleaf pine, 870 lbfHackberry, 880 lbfWater tupelo, 880 lbfSande, 900 lbfOcote pine, 910 lbfPaper birch, 910 lbfBlack cherry, 950 lbfRed maple, 950 lbfRoble, 960 lbfTeak, 1,000 lbfBlack walnut, 1,010 lbfAlbarco, 1,020 lbfSouthern magnolia, 1,020 lbfSouthern red oak, 1,060 lbfAvodire, 1,080 lbfManni, 1,120 lbfAndiroba, 1,130 lbfChestnut oak, 1,130 lbfOregon ash, 1,160 lbfBlack maple, 1,180 lbfOvercup oak, 1,190 lbfWater oak, 1,190 lbfGreen ash, 1,200 lbfBlack oak, 1,210 lbfLaurel oak, 1,210 lbfKapur, 1,230 lbfCaribbean pine, 1,240 lbfSwamp chestnut oak, 1,240 lbfIroko, 1,260 lbfYellow birch, 1,260 lbfKeruing, 1,270 lbfAngelique, 1,290 lbfMersawa, 1,290 lbfNorthern red oak, 1,290 lbfAmerican beech, 1,300 lbfRamin, 1,300 lbfRock elm, 1,320 lbfWhite ash, 1,320 lbfPost oak, 1,360 lbfWhite oak, 1,360 lbfScarlet oak, 1,400 lbfSepetir, 1,410 lbfSugar maple, 1,450 lbfWillow oak, 1,460 lbfSweet birch, 1,470 lbfPin oak, 1,510 lbfSapele, 1,510 lbfAfrormosia, 1,560 lbfHoneylocust, 1,580 lbfPeroba de campos, 1,600 lbfOpepe, 1,630 lbfBlack locust, 1,700 lbfPilon, 1,700 lbfKempas, 1,710 lbfPara-angelim, 1,720 lbfPiquia, 1,720 lbfPeroba rosa, 1,730 lbfAngelin, 1,750 lbfBenge, 1,750 lbfShellbark hickory, 1,810 lbfPurpleheart, 1,860 lbfShagbark hickory, 1,880 lbfJarrah, 1,910 lbfDegame, 1,940 lbfMockernut hickory, 1,970 lbfKarri, 2,040 lbfPignut hickory, 2,140 lbfSucupira, 2,140 lbfGoncalo alves, 2,160 lbfMora, 2,300 lbfCourbaril, 2,350 lbfGreenheart, 2,350 lbfTropical oak (roble), 2,500 lbfBubinga, 2,690 lbfBrazilian rosewood, 2,720 lbfKaneelhart, 2,900 lbfMacawood, 3,150 lbfIndian rosewood, 3,170 lbfBulletwood, 3,190 lbfAzobe, 3,350 lbfManbarklak, 3,480 lbfMarishballi, 3,570 lbfIpe, 3,680 lbfBur oak · 1,370 lbfIpe01,0002,0003,0004,000 lbf← softerharder →

Six measures

Bur oakU.S. hardwoods medianOther woods

  • Stiffness

    1.03 M psi7.1 GPa6th most flexible of 155
    0.54 M psi4.06 M psi
    36% below the U.S. hardwoods median

  • Bending strength

    10,300 psi71.0 MPa42nd weakest of 155
    4,300 psi29,900 psi

  • Janka hardness

    1,370 lbf6,094 N44th hardest of 155
    240 lbf3,680 lbf
    12th of 53 U.S. hardwoods

  • Cupping tendency

    2.0045th highest of 155
    1.092.90

  • Density

    0.580.64 at 12% MC46th heaviest of 155
    0.250.96

  • Shrinkage across the face

    8.8%radial 4.4%46th highest of 155
    3.5%12.7%

For its weight: stiffness-to-weight 1.78 (155th of 155); strength-to-weight 17,759 psi (154th of 155).

How much it moves

Both its face shrinkage (8.8%) and its T/R ratio (2.00) sit in the middle half of the list.

0.53 in.

off a 6-inch flatsawn board, green to oven-dry; quartersawn 0.26 in.

Tangential
8.8%
Radial
4.4%
Volume
12.7%
T/R ratio
2.00 (110th most stable of 155)
6 in. green (dashed)5.47 in. dry · −8.8%
Flatsawn
6 in. green (dashed)5.74 in. dry · −4.4%
Quartersawn

End view, shrinkage drawn 3× life size.

Closest substitutes

  • Hackberry

    36% softer · 16% lighter · shrinks 0.1 points more across the face

  • Oregon ash

    15% softer · 14% lighter · shrinks 0.7 points less across the face

  • Water tupelo

    36% softer · 21% lighter · shrinks 1.2 points less across the face

Compare with the first two

Among the oaks

5th hardest of 15, lbf; the neighbours either side are shown, the rest are on the oaks page.

Laboratory values

Its most unusual laboratory figure is stiffness (modulus of elasticity): 6th lowest of the 155 woods with a published value.

PropertyGreenDry, 12% MCChange when driedMetric, 12% MC
Modulus of elasticity0.88M psi1.03M psi+17%7.10GPa
Compression perpendicular680psi1,200psi+76%8.30MPa
Modulus of rupture7,200psi10,300psi+43%71MPa
Side hardness1,110lbf1,370lbf+23%6,094N
Tension perpendicular800psi680psi−15%4.70MPa
Compression parallel to grain3,290psi6,060psi+84%41.8MPa
Shear parallel to grain1,350psi1,820psi+35%12.5MPa
Work to maximum load10.7in-lbf/in³9.80in-lbf/in³−8%67.6kJ/m³
Impact bending44in.29in.−34%737mm

Wood Handbook Table 5-3b, Table 4-3. Data & method · Guides