Working with Ariella in Wood and Epoxy Tabletops
Ariella is an African timber sourced from species in the genus Brachystegia, including Brachystegia laurentii, Brachystegia mildbraedii, Brachystegia nzang, and Brachystegia zenkeri. Documented in the CIRAD Tropix technical sheet, this hardwood offers attractive warm tones and workable density, making it a viable candidate for custom furniture, cabinetwork, and epoxy river builds when handled with proper moisture controls.
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Brachystegia laurentii, Brachystegia mildbraedii, Brachystegia nzang (synonymous), Brachystegia zenkeri, Brachystegia p.p. | |
| Colour / texture / grain | Light brown; texture medium; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.56 | about 35.0 lb/ft³; a 2-inch-thick slab weighs about 5.8 lb per sq ft |
| Monnin hardness (12% MC) | 2.9 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 6.0 % | green to oven-dry |
| Total radial shrinkage | 3.7 % | green to oven-dry |
| Ratio St/Sr | 1.6 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.40 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 28 % | |
| Thermal conductivity | 0.19 W/(m·K) | |
| Crushing strength (12% MC) | 49 MPa | about 7,110 psi |
| Static bending strength (12% MC) | 85 MPa | about 12,330 psi |
| Modulus of elasticity (12% MC) | 12,400 MPa | about 1,798,000 psi |
| Decay (fungi) resistance | Durability class 3 – moderately durable | |
| Termite resistance | Class M – moderately durable | |
| Dry-wood borer resistance | Class D – durable (sapwood demarcated, risk limited | |
| Heartwood treatability | Class 3 – poorly permeable | |
| Use class from natural durability | Class 2 – inside or under cover (dampness possible) | |
| Drying | rate slow; distortion: high risk; checking: high risk; collapse: yes; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 55–65 °C | about 131–149 °F |
| Machining | blunting normal; saw teeth: ordinary or alloy steel; cutting tools: ordinary | |
| Nailing and screwing | Good | |
| CITES status | This species is not listed in the CITES Appendices (Washington Convention 2025). |
Values from the CIRAD Tropix technical sheet (average values for mature wood, 12% moisture content where noted). US-unit conversions are calculated by BigEpoxy (1 MPa = 145.04 psi; density = specific gravity × 62.43 lb/ft³).
What does Ariella look like and how wide are the slabs?
Ariella heartwood is light brown, frequently highlighted by copper brown veins that bring subtle visual warmth to a tabletop. It features a medium texture and grain that runs straight or slightly interlocked. One distinct aspect of the species is its clearly demarcated, very wide sapwood layer, measuring 10 to 15 cm across. With log diameters ranging from 80 to 120 cm, builders can source substantial slab widths suitable for full-size dining and conference tables. Slabs should be examined closely for wind shakes, which are noted as an occasional natural defect in the logs.
How heavy and hard is Ariella for everyday tabletop use?
At 12% moisture content, Ariella has a specific gravity of 0.56, giving it an average density of about 35.0 lb/ft³. For tabletop builders calculating base support, a 2-inch-thick slab weighs approximately 5.8 lb per sq ft. In terms of surface resistance, CIRAD reports a Monnin hardness of 2.9. Monnin hardness is a French testing scale where higher numbers reflect harder wood (distinct from Janka testing). The species is described as varying from soft to fairly hard, providing sufficient body for indoor furniture, flooring, and interior joinery while remaining easy to move in the shop.
How does Ariella shrink and move next to an epoxy river?
Dimensional movement is critical whenever wood is locked alongside rigid epoxy resin. Ariella exhibits a total tangential shrinkage of 6.0% and a total radial shrinkage of 3.7%, yielding a tangential-to-radial shrinkage ratio of 1.6. Its coefficient of volumetric shrinkage is 0.40% per 1% change in moisture content, with a fiber saturation point of 28%. Because a lower shrinkage ratio indicates less tendency to cup, a 1.6 ratio shows balanced cross-grain behavior. However, to avoid placing stress along the wood-resin bond line, the wood must be brought to indoor equilibrium moisture content and sealed thoroughly according to your resin manufacturer’s guidelines.
What drying risks should table builders watch out for?
Drying Ariella requires patience and care. The drying rate is classified as slow, and CIRAD notes a high risk of distortion as well as a high risk of checking. Collapse is also documented as a risk during the seasoning process, though there is no known specific risk of casehardening. When kiln-drying mature stock, suggested schedule temperatures range from 55 to 65 °C (about 131 to 149 °F). Slabs should be stickered evenly and monitored carefully to prevent surface checks or internal collapse before surfacing and mold assembly.
How does Ariella behave during sawing, machining, and fastening?
In the workshop, Ariella behaves predictably under standard tooling. Its blunting effect is rated as normal, requiring ordinary cutting tools and saw teeth made of ordinary or alloy steel. Although slight interlocked grain can be present, standard planing and routing practices yield clean surfaces. When assembling aprons or mounting table bases, fastening properties are rated as good for both nailing and screwing.
Is Ariella durable enough for indoor furniture, and does it need treatment?
Under natural durability testing, Ariella heartwood is rated as Class 3 (moderately durable) against xylophagous fungi and Class M (moderately durable) against termites. Resistance to dry-wood borers in the heartwood is Class D (durable), with insect risks primarily confined to the sapwood. Heartwood treatability is Class 3 (poorly permeable). Its natural durability corresponds to Use Class 2 (inside or under cover, where dampness is possible). Because the wide sapwood is easily attacked by insects, preservative treatment is recommended if sawn boards retain the live sapwood edge.
Is Ariella regulated under CITES?
Ariella is not listed in the CITES Appendices (Washington Convention 2025). Builders and clients can source this African timber for residential and commercial river tables without CITES trade restrictions.
Sources
Published October 31, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: If you plan to preserve the natural live edge on an Ariella slab, inspect the sapwood thoroughly before casting; CIRAD cautions that its unusually thick sapwood (10 to 15 cm) is readily attacked by insects and often requires preservative treatment before use. (Source: CIRAD Tropix 7 technical sheet: Ariella.)