Macacauba — Density, Movement, Workability & Cost

A marimba bar has to hold its tuned pitch through years of humidity swings in a concert hall or a touring truck, and macacauba (Platymiscium spp.) is the wood percussion builders trust with that job — 6.5% total volumetric shrinkage on a wood this dense is a genuinely remarkable number, among the most stable heavy hardwoods in commercial trade anywhere.

Stability that a tuned instrument actually depends on

At 68.4 lb/ft³ and 3,150 lbf on the Janka scale, macacauba is extremely dense and hard, and its stability isn't just a nice-to-have property — a marimba bar that moves unpredictably with the seasons goes out of tune, and this species simply doesn't move enough for that to become a practical problem the way it would with almost any other wood of comparable density.

The movement numbers behind the marimba trade's trust

Radial shrinkage of 2.7% against a tangential figure of 3.5% gives a 1.3 ratio — both absolute numbers are remarkably low, which is precisely the property a tuned instrument needs and most timber simply doesn't offer. Take a 3"-wide marimba bar blank from a 9% moisture content down to a dry 6% and it moves barely a hundredth of an inch, 0.011" (0.3mm), across the width; a wider or narrower bar runs through the wood movement calculator. That same blank, 1/2" thick and 18" long, weighs about 1.1 lb on the wood weight calculator.

Gluing an oily, dense surface, and a colour that deepens

Given the natural oiliness of a wood this dense, a solvent wipe before gluing and epoxy for anything load-bearing are the standard, reliable approach. It polishes to a natural gloss, and the colour deepens from a fresh orange-red toward a rich brown-red with age and light exposure — an expected, gradual shift rather than a defect.

Durability, cost, and a name that covers more than one wood

The heartwood is very durable, though the pale sapwood carries none of that resistance. It runs roughly $20 per board foot — premium tier, on this site's scale. Marimba bars, guitar backs and sides, turnery, flooring, and fine furniture round out its markets. Worth knowing before you buy: the trade name "granadillo" gets applied to several unrelated woods across Latin America, so purchasing on the botanical name — Platymiscium specifically — rather than the trade name alone is the only reliable way to know what you're actually getting.

A regulatory wrinkle worth knowing about

One specific species within this genus, listed by CITES as Platymiscium parviflorum — the accepted name for what older lumber lists sometimes call P. pleiostachyum — carries an Appendix II listing under annotation #4, a notably broader net than the timber-specific annotations used for many other regulated woods: it catches parts and derivatives generally, not just raw boards. The remaining macacauba species in the genus are unlisted, and only a botanical name on the invoice tells you which you actually have.

What people actually ask about macacauba

What other woods do marimba builders reach for when macacauba isn't available or is too expensive for a project? Padauk and bubinga are the common alternates, chosen for reasonably low shrinkage and dense, resonant tone, though neither builder-community consensus rates them as consistently pitch-stable across seasons as macacauba, which is why it remains the reference standard rather than being fully displaced.

Does the botanical-name confusion around "granadillo" cause any CITES compliance problems for buyers? It can — a shipment invoiced simply as "granadillo" without a species-level botanical name is exactly the kind of paperwork gap customs officials flag, since it's impossible to confirm from the trade name alone whether the regulated Platymiscium parviflorum is actually inside the crate.

Does a botanical name on the invoice guarantee the wood is legally sourced, or just correctly identified? Only identification — a correct species name tells you which CITES rules apply, but it says nothing about chain of custody, so a buyer wanting assurance the specific board was legally harvested and exported still needs separate sourcing documentation from the supplier.

Macacauba's shrinkage figures come from Table 4-4, and its density and Janka hardness from Table 5-5b, of the USDA Forest Products Laboratory's Wood Handbook (FPL-GTR-190, 2010), which lists the species as "Macawood." CITES status is read from the appendices valid 5 March 2026.