Comparing Shagbark Hickory and White Oak for River Tables
Choosing between Shagbark hickory and White oak for a custom epoxy river table involves balancing mechanical strength against seasonal wood movement. Both species are dense North American hardwoods that create striking tabletops when combined with casting resin, but their engineering properties differ significantly. All baseline figures discussed here are drawn from the USDA Forest Products Laboratory Wood Handbook (FPL-GTR-282, 2021).
Figures from the USDA Wood Handbook (FPL-GTR-282), Tables 4-1, 4-3, 5-3b, 13-5 and 14-1. Clear, straight-grained specimens; real slabs vary.
| Property | Shagbark hickory | White oak |
|---|---|---|
| Specific gravity (12% MC) | 0.72 | 0.68 |
| Side hardness, lbf (12% MC) | 1,880 | 1,360 |
| Modulus of rupture, lbf/in² (12% MC) | 20,200 | 15,200 |
| Modulus of elasticity, million lbf/in² (12% MC) | 2.16 | 1.78 |
| Compression perpendicular to grain, lbf/in² (12% MC) | 1,760 | 1,070 |
| Radial shrinkage, green to ovendry (%) | 7.0 | 5.6 |
| Tangential shrinkage, green to ovendry (%) | 10.5 | 10.5 |
| Volumetric shrinkage, green to ovendry (%) | 16.7 | 16.3 |
| Dimensional change coefficient, tangential (per 1% MC) | 0.00411 | 0.00376 |
| Dimensional change coefficient, radial (per 1% MC) | 0.00259 | 0.00194 |
| Green MC of heartwood (%) | — | 64 |
| Tangential/radial shrinkage ratio (calculated) | 1.5 | 1.9 |
| Heartwood decay resistance (Table 14-1) | Slightly or nonresistant | Resistant |
Density and Weight Considerations
At 12% moisture content, Shagbark hickory has a specific gravity of 0.72 compared to 0.68 for White oak (green values are 0.64 and 0.60, respectively). This higher density means hickory slabs will be heavier for a given board volume. For large dining tables or conference tops, this extra weight requires robust base joinery and solid support framing under both the wood and resin components.
Dent Resistance and Surface Durability
Surface toughness is critical for dining and work surfaces that face impact and concentrated loads:
- Side Hardness: At 12% moisture content, Shagbark hickory measures 1,880 lbf on the side hardness test, whereas White oak tests at 1,360 lbf (green values are 1,460 lbf and 1,060 lbf).
- Compression Perpendicular to Grain: Hickory reaches 1,760 psi at 12% moisture content (840 psi green), while White oak reaches 1,070 psi (670 psi green).
Hickory provides substantial resistance against point loads, chair bumps, and heavy tabletop objects, making it less prone to localized indentation along the exposed wood edges.
Stiffness, Bending Strength, and Long Overhangs
When engineering tabletops with long spans between trestles or cantilevered overhangs, bending strength and stiffness dictate how much the wood will deflect under load:
- Modulus of Rupture (MOR): Hickory exhibits a dry MOR of 20,200 psi versus 15,200 psi for White oak (green MOR is 11,000 psi for hickory and 8,300 psi for White oak).
- Modulus of Elasticity (MOE): Hickory reaches 2.16 million psi dry (1.57 million psi green), while White oak reaches 1.78 million psi dry (1.25 million psi green).
- Parallel Shear Strength: At 12% moisture content, hickory achieves a shear strength of 2,430 psi parallel to the grain, compared to 2,000 psi for White oak (green values are 1,520 psi and 1,250 psi).
Because hickory possesses both higher stiffness and higher bending strength, it resists deflection exceptionally well across wider unsupported spans.
Seasonal Movement, Shrinkage, and Moisture
Wood movement is the primary stressor on an epoxy-to-wood bondline. As ambient humidity shifts across seasons, wood expands and contracts across its grain:
- Total Shrinkage: From green to ovendry, hickory shrinks 7.0% radially, 10.5% tangentially, and 16.7% volumetrically. White oak shrinks 5.6% radially, 10.5% tangentially, and 16.3% volumetrically.
- T/R Ratio: Hickory exhibits a calculated tangential-to-radial shrinkage ratio of 1.5, whereas White oak has a ratio of 1.9. A lower ratio generally indicates more uniform shrinkage between dimensions, reducing distortion during drying.
- Dimensional Change Coefficients: Per 1% change in moisture content, hickory moves 0.00259 radially and 0.00411 tangentially. White oak moves 0.00194 radially and 0.00376 tangentially.
- Green Moisture Content: White oak heartwood averages 64% moisture content when green (sapwood averages 78%), while hickory green moisture data is unlisted in the summary tables.
White oak moves slightly less in service per percentage change in moisture, especially in the radial direction, placing lower overall strain on the epoxy interface in shifting environments.
Heartwood Decay Resistance
According to Table 14-1 of the USDA Wood Handbook, White oak heartwood is rated as Resistant to decay, while Shagbark hickory heartwood is rated as Slightly or nonresistant. For indoor dining tables, biological decay is rarely a concern if the wood is properly dried. However, for covered patio tables or areas exposed to intermittent dampness, White oak offers a distinct natural advantage.
Which to Pick When
- Choose Shagbark Hickory: When you need maximum surface hardness against dents, maximum stiffness for extended spans or thinner tops, or when you prefer a lower T/R ratio across slab sections.
- Choose White Oak: When you prioritize lower overall seasonal movement per humidity change, require natural heartwood decay resistance, or want slightly reduced overall tabletop weight.
For either wood species, follow your resin manufacturer’s technical data sheet for surface preparation, moisture limits, and pour depth guidelines before casting.
Sources
Published October 28, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: For maximum impact resistance, the USDA Wood Handbook reports Shagbark hickory absorbing an impact bending drop of 67 inches at 12% moisture content (74 inches green), compared to 37 inches dry (42 inches green) for White oak. (Source: USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-282, 2021).)