Is your timber sustainable? Legality, and what FSC or PEFC certified really means
Written by Scott Jones, The Stair Guys, independent staircase measuring and sourcing specialists·Last updated
Ask where a staircase timber comes from and you will hear two words used as if they mean the same thing: legal and sustainable. They do not. A timber can be perfectly legal to sell and tell you nothing about whether the forest it came from is being looked after. Knowing the difference is the difference between buying on evidence and buying on a logo.
Legal is not the same as sustainable
Two separate rulebooks are at work. Legality is covered by timber-legality law (the UK Timber Regulation, which bans illegally harvested wood) and by CITES, which controls trade in endangered species. Both prove a timber is legal to place on the market. Neither says a word about whether it was grown and felled sustainably.
Sustainability claims live under a different regime entirely: consumer-protection law, now the Digital Markets, Competition and Consumers Act, with the Competition and Markets Authority Green Claims Code as the guidance that interprets it. Under that regime any "responsibly sourced" claim has to be specific, evidenced and fair. So "we source legally" is a fact about compliance. "We source sustainably" is a claim that has to be backed up. Treating the first as if it proves the second is the single most common way this goes wrong.
What "certified" actually certifies
When a maker says it is FSC or PEFC certified, that almost always means it holds a chain-of-custody certificate: its system for tracking and accounting for timber is independently audited. That is a real, useful thing. It is not the same as saying every board it sells was grown in a certified forest.
The label on the product is where the detail sits. FSC 100 percent means the whole product came from certified forests. FSC Recycled means it is reclaimed material. FSC Mix, which is the label you see most on joinery, is a mass-balance system: it blends certified, recycled and risk-screened "controlled wood", and works on volume credits rather than tracing your exact board back to a certified forest. That is a disclosed accounting method that lets certified supply scale, not a loophole, but it does mean an FSC Mix board is not guaranteed to be certified-forest origin. Controlled wood, for its part, is screened to exclude the worst sources such as illegal logging. It is a floor, not proof of positive management.
FSC and PEFC: the difference
They are built differently. FSC runs one global forest-management standard and accredits the bodies that certify against it, and it is governed through environmental, social and economic chambers with an equal say. PEFC is an umbrella that endorses independently developed national schemes against its benchmarks, and it has historically been more forest-owner and industry led. PEFC certifies the larger area of forest worldwide, much of it European softwood, while FSC tends to be stronger in UK retail and tropical hardwood.
FSC is generally regarded as the stronger scheme, and both have documented failures where governance was weak. The two do not recognise each other, so a product cannot mix FSC and PEFC material and be sold as either. In UK public procurement, FSC, PEFC and Grown in Britain are all treated as Category A evidence of legal and sustainable timber, so none of them is "the official UK one".
The honest bottom line
Certification is worth having and worth asking for. The schemes deliver legally verified supply chains, screen out the worst sourcing and put an independent auditor in the loop, and the strongest field research backs them up: a 2024 study in Nature found FSC-certified concessions in the Congo Basin held around 2.7 times more large mammals than comparable non-certified forest. What certification does not do is guarantee that every fibre came from a well-managed forest, and the Mix label in particular is easy to read as more than it promises. So treat FSC or PEFC as the baseline to expect, then ask the questions that go beyond the logo. That is where a maker either has real answers or does not.
SourceCMA Green Claims Code (guidance on environmental claims), gov.uk
SourceFSC, what the FSC labels mean
Frequently asked
Does FSC certified mean the wood came from a sustainable forest?+
Not on its own. FSC certified usually means a company holds an audited chain-of-custody certificate for how it tracks timber. Only an FSC 100 percent label means the whole product came from certified forests. FSC Mix, the label you see most on joinery, uses a volume-credit system that can legitimately include risk-screened non-certified wood.
What is the difference between FSC and PEFC?+
FSC runs one global standard and accredits its certifiers, governed through environmental, social and economic chambers. PEFC is an umbrella that endorses national schemes against its benchmarks and has been more industry led. PEFC covers the larger forest area worldwide, FSC is generally regarded as the stronger scheme, and the two do not recognise each other.
Is legally sourced timber the same as sustainably sourced?+
No. Legality is covered by timber-legality law and CITES, which prove a timber is legal to sell. Sustainability is a separate claim under consumer-protection law and the Green Claims Code, and it has to be specifically evidenced. A timber can be entirely legal and still tell you nothing about how the forest is managed.
Sources
Primary sources we used and reconciled before publishing.
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