Wood is the only structural building material that, during its own biological formation, removes CO₂ from the atmosphere instead of emitting it — a growing tree fixes carbon into its woody tissue through photosynthesis, about 1 kg of CO₂ for every kg of dry wood produced. It is a real advantage, often cited as a decisive argument in favour of structural timber. But the full picture is more nuanced than how it is presented in many commercial technical sheets, and the difference between wood that is genuinely sustainable and wood that only appears to be depends almost entirely on one factor: the management of the forest of origin.
FSC and PEFC: two certifications, two different governance models
The two most widespread forest certifications on the European market — FSC (Forest Stewardship Council) and PEFC (Programme for the Endorsement of Forest Certification) — share the stated goal (ensuring that wood comes from forests managed so as to maintain their productive and ecological capacity over time) but have different origins and governance. FSC was founded in 1993 from an initiative with a strong environmental and social component, with a governing council that includes non-governmental organizations, indigenous communities and industry in equal representation — a governance structure that tends to produce stricter standards on issues such as biodiversity protection and the rights of local populations. PEFC, born in 1999 as a more industry-driven initiative, works as an umbrella system that recognizes national forest certification standards developed country by country — a more flexible approach to local conditions, but sometimes criticized for less uniformity of criteria than FSC. In practice, for the European market, both certifications are considered acceptable in most public and private specifications, and the choice between the two often depends more on the regional availability of certified timber than on a clear qualitative preference.
The "carbon neutral" problem: cutting speed versus regrowth speed
The most misunderstood technical point in the debate on wood sustainability concerns the very concept of carbon neutrality. It is true that a felled tree would sooner or later release its embodied carbon anyway if left to decompose naturally in the forest — so using it in a building, where the carbon stays stored for decades or centuries, is often preferable to natural decomposition from a climate standpoint. But this reasoning holds at the level of the single tree, not at the level of the forest system: if a forest's harvest rate exceeds its regrowth rate, the forest's overall carbon stock decreases over time, regardless of what happens to the wood once cut. Sustainably managed Nordic and European forests (Finland, Sweden, Austria, much of Alpine Italy) typically operate with harvest rates below net annual growth, maintaining or increasing the overall forest stock — a condition that makes the carbon balance of construction timber genuinely favourable. Logging of primary or tropical forests not managed sustainably reverses this balance, and no certification can retroactively correct an unsustainable harvest at the source.
Cascading use: the hierarchy that matters more than CO₂ alone
A lesser-known but increasingly central principle in European forest policy is "cascading use": the same wood resource should pass, in order, through the highest-value-added, longest-lasting uses before being directed to lower-value ones. The ideal sequence is: structural construction timber (decades of carbon storage) → furniture and long-lasting products → particleboard and composites (from offcuts and lower-grade wood) → paper and pulp → and finally, only as a last option, combustion for biomass energy production. Burning high-quality virgin wood to produce energy — a growing practice under some renewable-incentive schemes — is considered by forestry experts a waste of the long-term carbon-storage function that structural timber would offer, if only it were directed to the correct use in the hierarchy. The EU Deforestation Regulation (EUDR), phased in progressively from 2023, precisely strengthens supply-chain traceability to prevent wood from unregulated logging from entering the European market under any final destination.