Pau d'arco

Pau d'arco is the wood of Tecoma ochracea, a flowering tree of the trumpet-vine family (Bignoniaceae) native to tropical South America. The trees — long placed in the genus Tabebuia and its relatives — grow across the Amazon basin and the surrounding savannas of Brazil, Bolivia, Paraguay and northern Argentina, and are celebrated for their spectacular yellow, pink, or purple flowering displays. In the timber trade the wood and its close relatives are far better known as ipe or lapacho, and it is one of the heaviest, hardest commercial timbers on the market.

The name 'pau d'arco' is Portuguese for 'bow stick,' a reference to the wood's traditional use for hunting bows — a nod to its exceptional strength and elasticity. At a glance the timber is a warm reddish-brown to orange-brown, very dense and heavy, fine-textured, and remarkably durable, which is why it dominates the premium exterior decking and boardwalk market. On our sample the grain reads fine with distinct growth rings visible in the cross-section and a reddish-brown to orange-brown color.

The heartwood ranges from reddish-brown through olive- and orange-brown to a darker walnut brown, often with lighter and darker striping, and it darkens with age and light exposure; the sapwood is clearly distinct, pale yellowish to nearly white. A yellow-green powdery deposit called lapachol frequently sits in the pores and can be seen as a fine yellow dust in the grain — a useful identifying trait. Grain is straight to irregular or interlocked, texture is fine and even, and the wood carries a low to medium natural luster. On this sample the grain is fine with distinct growth rings visible in cross-section.

Pau d'arco is one of the densest woods in commerce, roughly 1,000–1,100 kg/m³ air-dry — dense enough that seasoned pieces sink in water. Its Janka hardness is about 3,670 lbf, placing it firmly in the very hard range, several times harder than white oak and among the hardest woods used in ordinary construction. It is correspondingly strong, stiff, and heavy.

Natural durability is outstanding. The heartwood is rated very durable, with excellent resistance to decay, brown- and white-rot fungi, termites, and marine borers, and it also has a high natural resistance to fire. This combination of density and durability is the wood's defining quality.

Pau d'arco / ipe is above all an exterior timber. It is the benchmark wood for high-end decking, boardwalks, piers, and marine construction — famously used for public boardwalks and promenades — as well as exterior cladding, siding, fencing, railings, and outdoor furniture, where its density and decay resistance let it survive decades of weather with minimal maintenance.

Indoors and in heavy service it is used for flooring (including commercial and industrial floors), stair treads, tool handles, and other applications demanding wear resistance and strength. Its hardness and stability also suit it to turning and specialty items, and its historical uses include bows and other implements that exploited its strength and springiness. The related Tabebuia species are the source of lapacho / taheebo herbal preparations made from the inner bark, though that is a bark product rather than a use of the timber.

Pau d'arco is difficult to work because of its extreme density and interlocked grain. It has a strong dulling effect on cutting edges, so carbide tooling is effectively required for machining, and its weight and hardness make it hard on both hand tools and machinery. Interlocked grain tears out easily on planed and moulded surfaces, and the wood must be pre-drilled for nails and screws, which cannot be driven without splitting. It can be brought to a very smooth, glassy surface with sharp tooling.

Gluing is problematic: the wood is oily and extremely dense, so surface preparation, appropriate adhesives, and freshly machined faces are important for a sound bond. It finishes well once sealed but the natural oils and yellow lapachol deposits can interfere with some finishes and may bleed; exterior installations are commonly left to weather or maintained with penetrating oils. The fine yellow lapachol dust can stain surrounding materials and leach in wet conditions.

On safety, ipe/pau d'arco dust is a recognized irritant and sensitizer: fine dust from this wood is well documented to cause skin, eye, and respiratory irritation, dermatitis, and asthma-like symptoms, and the yellow lapachol powder is a particular irritant. Effective dust extraction, a good respirator, and skin and eye protection are strongly advised. The species is not listed under CITES.

Pau d'arco, traded as ipe or lapacho, is a widely available imported specialty hardwood sold mainly as decking boards, dimensional lumber, and flooring through decking and hardwood suppliers rather than general lumberyards. It sits at the upper end of the price band for exterior timber — considerably more expensive than pressure-treated softwood or cedar, reflecting its density, durability, and the labor of milling it — with premiums for long, clear, defect-free decking lengths.

The wood is not listed under CITES and remains freely traded, but ipe/lapacho species have drawn conservation concern because of heavy demand and largely wild harvest from South American forests; illegal logging and traceability have been ongoing issues in the trade. Responsibly sourced or FSC-certified stock is the preferable choice where available. Because several closely related Tabebuia, Handroanthus, and Tecoma species are sold interchangeably as ipe or lapacho, buyers wanting a specific species or verified origin should ask for documentation.