Beli Characteristics, Density, and Hardness
Beli (Julbernardia pellegriniana, with the synonym Paraberlinia bifoliolata) is an African timber detailed in the CIRAD Tropix technical sheet. Typical logs range from 80 to 100 cm in diameter, offering ample width for live-edge slabs and river table boards. The sapwood is clearly demarcated from the heartwood and measures between 10 and 15 cm in thickness. Visually, the wood features a warm brown color and is highly veined with alternate dark and light coloured streaks. Its grain runs straight or interlocked—with slight interlocked grain that is sometimes oblique—paired with a medium texture.
In terms of weight, Beli is a solid, substantial hardwood. At 12% moisture content, it has an average specific gravity of 0.77, which corresponds to a density of about 48.1 lb/ft³. For tabletop design, a 2-inch-thick slab weighs approximately 8.0 lb per sq ft. Its structural stiffness and strength are equally pronounced: CIRAD testing records a crushing strength of 68 MPa (about 9,860 psi), a static bending strength of 128 MPa (about 18,560 psi), and a modulus of elasticity of 17,840 MPa (about 2,587,000 psi).
Surface resistance is measured on the Monnin hardness scale, where Beli registers an average value of 5.6 at 12% moisture content. The Monnin scale is an established French testing metric where higher values reflect harder wood; it is completely distinct from the Janka scale and must never be converted or interpreted as a Janka value. With a Monnin rating of 5.6, Beli provides durable surface resistance well suited for interior joinery, flooring, and fine cabinetwork.
Dimensional Movement and Epoxy River Stability
When embedding wood slabs alongside rigid epoxy resin, dimensional stability is a primary consideration. Wood expands and contracts as ambient relative humidity shifts, whereas cured resin remains stable. Beli exhibits a total tangential shrinkage of 8.9% and a total radial shrinkage of 4.3% from green to oven-dry, resulting in a tangential-to-radial shrinkage ratio (St/Sr) of 2.1. Its coefficient of volumetric shrinkage is 0.60% per % change in moisture content, with a fibre saturation point of 27%.
Because the tangential movement is roughly double the radial movement, wide flatsawn sections will experience more lateral movement across their width than quartersawn boards. If the wood undergoes moisture swings after being cast in place, high shrinkage differentials can generate stress at the epoxy bond line. Stabilizing the board’s moisture content before the pour and sealing all surfaces afterward are essential steps to keep these stresses minimal.
Drying Behavior, Machining, and Fabrication Notes
The drying rate for Beli is classified by CIRAD Tropix as normal to slow. Seasoning presents a slight risk of distortion and a slight risk of checking, while casehardening and collapse show no known specific risk. Suggested kiln drying programs operate between 53 and 65 °C (about 127 to 149 °F). Slabs should be dried carefully, as CIRAD notes a possibility of discoloration during the drying cycle. Builders should also anticipate lower lumber yields, as end-uses can be limited by the possible presence of natural defects.
In the workshop, Beli exhibits a normal blunting effect on tooling. It cuts cleanly with ordinary cutting tools and sawteeth made from ordinary or alloy steel. However, woodworkers must account for reported risks of distortion during machining, especially during planing operations. When mounting hardware or securing tabletops to leg assemblies, nailing and screwing hold well, but pre-boring is necessary to prevent splitting.
In terms of biological resistance, Beli heartwood is rated Durability class 3 (moderately durable) against fungi, Class M (moderately durable) against termites, and Class D (durable) against dry-wood borers, with borer risk limited to the sapwood. Heartwood treatability is Class 3 (poorly permeable). CIRAD assigns the wood to Use class 2, which designates applications inside or under cover where dampness is possible. In global trade, Beli is not listed in the CITES Appendices (Washington Convention 2025).
| Property | CIRAD Tropix value | What it means / US units |
|---|---|---|
| Botanical name(s) | Julbernardia pellegriniana, Paraberlinia bifoliolata (synonymous) | |
| Colour / texture / grain | Brown; texture medium; grain straight or interlocked; interlocked grain slight | |
| Specific gravity (12% MC) | 0.77 | about 48.1 lb/ft³; a 2-inch-thick slab weighs about 8.0 lb per sq ft |
| Monnin hardness (12% MC) | 5.6 | French hardness scale; higher = harder (not a Janka value) |
| Total tangential shrinkage | 8.9 % | green to oven-dry |
| Total radial shrinkage | 4.3 % | green to oven-dry |
| Ratio St/Sr | 2.1 | closer to 1 = less cupping tendency |
| Coefficient of volumetric shrinkage | 0.60 % per % MC | volume change per 1% change in moisture content |
| Fibre saturation point | 27 % | |
| Thermal conductivity | 0.25 W/(m·K) | |
| Crushing strength (12% MC) | 68 MPa | about 9,860 psi |
| Static bending strength (12% MC) | 128 MPa | about 18,560 psi |
| Modulus of elasticity (12% MC) | 17,840 MPa | about 2,587,000 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 normal to slow; distortion: slight risk; checking: slight risk; collapse: no known specific risk; casehardening: no known specific risk | |
| Suggested kiln program temperatures | 53–65 °C | about 127–149 °F |
| Machining | blunting normal; saw teeth: ordinary or alloy steel; cutting tools: ordinary | |
| Nailing and screwing | Good but pre-boring necessary | |
| 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).
Pre-Pour Checklist for Beli River Tables
- Verify moisture equilibrium: Ensure the slab has reached interior equilibrium moisture content, as Beli has a volumetric shrinkage coefficient of 0.60% per % MC and a normal to slow drying profile.
- Inspect for drying defects and discoloration: Check for any checking, distortion, or color changes that may have occurred during kiln or air drying.
- Evaluate the sapwood margin: Inspect the 10 to 15 cm sapwood zone; dry-wood borer risk is limited to this sapwood band, so ensure it is sound or trimmed away based on project goals.
- Plane with shallow passes: Plane boards incrementally to monitor and reduce the known risk of distortion during machining.
- Prepare the river edge: Sand and thoroughly vacuum the live edge or sawn edge to clear dust and expose sound grain for adhesive contact.
- Apply a dedicated seal coat: Apply a thin epoxy seal coat along the casting faces and allow it to tack or cure per resin manufacturer instructions to prevent air escape from medium-textured pores.
- Pre-bore all fasteners: Drill pilot holes for any mechanical fasteners or mounting threaded inserts, as pre-boring is required to avoid cracking the wood.
Sources
Published October 31, 2026. Sources are linked in the text.
Header image: original graphic by BigEpoxy.com.
Staff note: According to the CIRAD Tropix technical sheet, French standard NF B 52-001-1 (2018) provides visual grading strength class D40 for structural applications, while French fire safety standards classify material over 14 mm thick as M3 (moderately inflammable) and material under 14 mm thick as M4 (easily inflammable). (Source: CIRAD Tropix 7 technical sheet: Beli.)