Kwila Decking Has a Provenance Problem

Image note: reddish-brown staining is a practical issue sometimes seen when fresh Kwila/Merbau extractives wash onto pale concrete or paving.

Kwila is beautiful timber. That is part of the problem.

Also sold internationally as merbau, Kwila has been prized for decking, flooring, outdoor furniture and joinery because it is dense, durable and richly coloured. Those are real material strengths. But the same value has made merbau one of the clearest examples of how tropical timber can hide illegal logging, forged paperwork, weak enforcement, land-rights abuse and supply-chain laundering.

The issue is not that every piece of Kwila in New Zealand is illegal. The issue is that Kwila comes from a high-risk tropical hardwood supply chain where serious illegality has been documented repeatedly. If a seller cannot show the exact species, forest origin, certificate scope and chain of custody for the specific timber being sold, buyers should treat broad claims like “sustainable hardwood” or “ethically sourced Kwila” as marketing until proven otherwise.

For context, international research usually uses the name merbau. In New Zealand, the same timber is commonly sold as Kwila. TRAFFIC identifies merbau/Kwila as timber from Intsia species and records its major range states and trade routes in its Review of trade in Merbau from major range States.

That is why we think New Zealand buyers should ask harder questions before defaulting to Kwila for decking, outdoor furniture or architectural timber.

Kwila and merbau are the same conversation

Kwila is the New Zealand trade name commonly used for merbau, usually from the Intsia genus. The timber grows across parts of Southeast Asia and the Pacific, with important commercial supply linked to Indonesia and Papua New Guinea.

That naming matters. A New Zealand buyer may search for “Kwila decking”, while the strongest environmental and legal research is usually filed under “merbau”. When the reports talk about illegal merbau, they are talking about the timber New Zealanders commonly know as Kwila.

The problem is provenance

By the time Kwila reaches a New Zealand building site or retail rack, it may have passed through forest operators, millers, exporters, importers, wholesalers and retailers. Each handoff creates distance between the buyer and the forest where the tree was cut.

That distance matters because merbau has a documented history of illegal logging and trade. The Environmental Investigation Agency and Telapak’s report The Last Frontier describes merbau as the main target of illegal loggers in Indonesian Papua and documents smuggling syndicates, forged paperwork, corruption, and the role of brokers and buyers across international supply chains.

Greenpeace’s Merbau’s Last Stand describes illegal merbau trading routes including forged Malaysian documentation, illegal concessions in Papua New Guinea, illegal Indonesian timber and smuggling of squared logs. TRAFFIC’s technical review also records multiple illegal merbau trade cases, including seizures in West Papua and shipments linked to China.

This is not a vague “imported timber can be bad” argument. Merbau/Kwila has a specific, well-documented risk profile.

Stolen land, weak consent and corrupted paperwork

In Papua New Guinea, the legal problem is often not simple chainsaw-in-the-night smuggling. It can be more complicated and more troubling: licences issued or extended in breach of rules, weak consultation with customary landowners, harvesting breaches, agricultural clearing permits used to access timber, and systems that look official while still failing the people whose land and forests are affected.

Chatham House’s 2014 assessment of illegal logging in Papua New Guinea found that illegal practices were widespread and that the majority of timber production in PNG was likely illegal in some way. It specifically points to licences issued or extended in breach of regulations, including rules around consultation with indigenous landowners, as well as extensive breaches of harvesting regulations.

The Oakland Institute’s The Great Timber Heist goes further into PNG’s Special Agriculture and Business Leases. It reports widespread lack of free, prior and informed consent, fraud, misconduct, incompetence and corruption in land deals that opened forests to logging.

That is why we are careful with the word “legal”. In high-risk timber supply chains, legality is not just whether there is a document attached. The real question is whether the rights, consent, harvest rules, transport chain and export process behind that document can stand up to scrutiny.

Certification helps, but it is not a blindfold

FSC certification matters. A genuine FSC claim for the exact product is better than vague supplier reassurance. It can improve forest management and it gives buyers something more concrete to check.

But certification is not a magic shield. A supplier’s chain-of-custody certificate is not the same as proof that every product they sell is FSC certified. A label only helps if it applies to the specific product, batch and claim being made. Even then, high-risk tropical species still deserve batch-level evidence.

FSC ANZ itself describes West Papuan merbau as “a highly valuable tropical timber that faces deforestation as a prime target for illegal logging and forest conversion” in its article on Bunnings and responsible merbau sourcing. That does not make FSC-certified merbau worthless. It shows the opposite: certification was pursued because the underlying risk was serious.

The certification problem is also visible in legality schemes. Mongabay’s report Legal failings leave illegal loggers unpunished and certified in Indonesia summarises EIA and Kaoem Telapak findings that some companies involved in illegal merbau trade were still able to hold or regain Indonesia’s timber legality certificates. In another Mongabay report, a Papua sawmill linked to a major plantation project lost its legality certificate after allegations of forged permits were investigated.

So the point is not “FSC Kwila is illegal”. That would be too broad. The point is more useful: buyers should verify the specific claim being made for the timber in front of them.

If a retailer cannot show the certificate code, the certified product scope, the forest of origin and the chain of custody for the actual Kwila boards being sold, then “certified” should be treated as a claim to verify, not a guarantee to accept on faith.

The practical issue customers notice: tannin bleed

There is also a practical drawback that has nothing to do with ethics. Fresh Kwila can bleed. When it gets wet, it may release dark reddish-brown extractives that can stain pale concrete, tiles, paving, walls and nearby surfaces.

This does not make Kwila unusable. It means it should be specified honestly. Pre-weathering, drainage, fixing details, surface protection and maintenance expectations all matter. Outdoor timber always needs care.

Questions to ask before choosing Kwila

Where a local alternative fits

This is where West Coast Red Heart Beech enters the conversation: not as a slogan, not as a purity test, and not as a claim that local timber is automatically perfect. We humbly offer it as a practical alternative where the site, specification and maintenance expectations make sense, and where the supply story is shorter, closer and easier to verify.

At Innate, we use West Coast Red Heart Beech where it suits the product, exposure, detailing and maintenance expectations. For decking and outdoor applications, the important wording is heartwood and correct specification. Outdoor timber is never “fit and forget”, whether it is local or imported.

New Zealand indigenous timber harvesting and milling is controlled under the Forests Act framework, including MPI Sustainable Forest Management permits and plans for approved native timber production. That framework does not remove the need to specify timber properly, but it gives New Zealand buyers a more direct legal and provenance context than a long tropical hardwood supply chain.

If provenance is part of your brief, we can show you our West Coast Red Heart Beech decking and the companion guide, NZ Beech Decking: A Local Alternative to Kwila. It will not be the right answer for every site, but it is a transparent local option worth comparing before defaulting to imported tropical hardwood.

Kwila vs West Coast Red Heart Beech

The useful question is not simply which timber is “best”. It is which timber fits the site, source expectations, finish, maintenance plan and budget.

Question	Kwila / Merbau	West Coast Red Heart Beech
Where does it come from?	Imported tropical hardwood, commonly associated with Southeast Asia and the Pacific region.	New Zealand native timber from the West Coast.
What is the core risk?	Long, high-risk supply chains with documented illegal logging, weak enforcement and laundering concerns.	Needs correct specification, heartwood selection, detailing, finish and ongoing care.
What should you ask for?	Species, exact origin, certificate code, product scope, chain-of-custody evidence and legality documents for the batch.	Species, grade, heartwood suitability, finish system, fixing advice and project suitability.
Practical issue	Known for tannin bleed that can stain pale paving and concrete when new.	Still a natural timber requiring exterior detailing and maintenance, but not chosen for the same heavy red bleed associated with Kwila.
Best fit	When imported tropical hardwood is acceptable and sourcing is proven, not merely claimed.	When local provenance, natural character and a shorter supply chain matter.

How we would choose

If someone brought this decision into the workshop, we would not start with a slogan. We would ask where the timber is going, how exposed it will be, whether staining nearby surfaces matters, what maintenance the owner will realistically do, and whether provenance is part of the brief.

For some jobs, a properly verified imported hardwood may still be chosen. This article is not here to shame that decision. It is here to say that “properly verified” is doing a lot of work in that sentence. With Kwila, the burden of proof should sit with the seller, not the customer.

For many New Zealand homes, outdoor tables, decking details and custom furniture pieces, the useful next step is simply to compare Kwila with a well-specified local option before committing.

FAQ: Kwila decking and local timber alternatives

Is Kwila illegal in New Zealand?

No. Kwila is not automatically illegal in New Zealand. The concern is that Kwila/Merbau can come from regions with documented illegal logging, forged paperwork, land-rights and traceability problems. Buyers should ask for current, product-specific evidence.

Is FSC-certified Kwila guaranteed to be legally logged?

No certification should be treated as a magic guarantee without checking the exact claim. Genuine FSC certification for the specific product is far better than vague sustainability language, but buyers should still ask for the certificate code, product scope, forest origin and chain-of-custody evidence for the actual timber being sold.

Does Kwila bleed?

Yes. Fresh Kwila/Merbau can release reddish-brown tannins when wet. These can stain concrete, paving, tiles and other pale surfaces if the timber is not detailed and managed carefully.

Is Kwila sustainable?

It depends on the source, documentation and supply chain. A generic sustainability claim is not enough. Ask where the timber came from, who verified it, and whether the product-specific paperwork can be checked.

What is a local alternative to Kwila?

For Innate, West Coast Red Heart Beech is the important local alternative to consider. It has a shorter New Zealand supply chain and a clearer material story when specified for the right use.

Can New Zealand Beech be used outside?

It can be used in outdoor applications when the timber, detailing, finish and maintenance plan suit the exposure. Outdoor timber always needs care, so the design and care expectations need to be clear from the start.

Considering a local alternative to Kwila?

References

Sources used include illegal merbau trade investigations, technical trade reviews, PNG legality and land-rights research, and reporting on certification/legality-system limits.

1. EIA/Telapak, The Last Frontier: Illegal Logging in Papua and China’s Massive Timber Theft
2. EIA/Telapak, Behind the Veneer: How Indonesia’s Last Rainforests are being Felled for Flooring
3. TRAFFIC, Review of trade in Merbau from major range States
4. Greenpeace, Merbau’s Last Stand
5. Chatham House, Illegal logging in Papua New Guinea
6. Oakland Institute, The Great Timber Heist
7. Mongabay, Legal failings leave illegal loggers unpunished and certified in Indonesia
8. Mongabay, Papua sawmill loses legal timber stamp over allegations of permit forgery
9. FSC ANZ, Bunnings, turning the tide