Durable wood without toxic preservatives — furfurylated wood (from agricultural residues), acetylated wood, thermally modified wood, naturally durable species and constructive protection — instead of CCA, creosote and biocidal impregnation

Replaces: CCA, creosote, pentachlorophenol and biocidal impregnations · Scope: construction and gardens · Evidence: high

The chemical problem#

• CCA (arsenic, chromium, copper) was the standard “green” pressure-treated wood for decades. Arsenic leaches into soil and onto children’s hands. The EU restricted CCA for consumer and residential uses (Directive 2003/2/EC), and the USA ended residential use (voluntary phase-out in 2003). Old CCA wood remains in playgrounds and gardens, and burning it releases arsenic.
• Creosote (on railway sleepers and poles) contains PAHs, including carcinogens. Its use is restricted in the EU, and old sleepers reused in gardens are a known hazard.
• Pentachlorophenol is listed under the Stockholm Convention on persistent organic pollutants (2015).
• All biocide-treated wood becomes hazardous waste at end of life.

Product overview#

Wood modification changes the wood itself so fungi and insects cannot use it, with no toxic biocides:

1. Furfurylated wood (e.g. Kebony, Norway): impregnated with furfuryl alcohol made from agricultural residues (sugar-cane bagasse, corn cobs) and cured into a polymer in the cell wall. Durability class 1–2, teak-like.
2. Acetylated wood (e.g. Accoya): reaction with acetic anhydride (acetic acid is the same compound as in vinegar) blocks the hydroxyl groups. Very high durability (class 1) and dimensional stability.
3. Thermally modified wood (ThermoWood, Finland; widespread in Russia and the Nordic region): heating to 180–230 °C in steam or nitrogen, with no chemicals. Good durability above ground.
4. Naturally durable species: larch heartwood (Larix sibirica, abundant in Russia), oak, black locust (Robinia).
5. Constructive (design) protection: keep wood dry (drainage, distance from soil, roof overhangs, ventilated fixings), which is the oldest and most effective protection.

Active ingredient / Composition#

Wood + furfuryl alcohol polymer (bio-based) / acetyl groups / heat; no metals or organochlorines.

Key facts#

Advantages#

• Safe for playgrounds, vegetable-garden beds, decks and docks near water.
• Uses fast-growing plantation wood (radiata pine, beech, spruce), and furfurylation uses farm residues.
• Better dimensional stability (less swelling, cracking).
• Stores carbon in long-lived products (the construction-timber bioeconomy).

Mode of action#

• Furfurylation/acetylation: the cell wall is bulked and hydroxyl groups are blocked, so moisture content stays below the level fungi need, and enzymes cannot recognize or degrade the wood.
• Thermal modification: hemicelluloses degrade and hydrophobicity increases.
• Design: keeps wood moisture below about 20 %, where decay fungi cannot grow.

Application#

Limitations#

• Higher price than CCA or copper-treated pine.
• Thermally modified wood is more brittle and less suitable for structural or ground-contact uses.
• Heavy-duty ground contact (poles, sleepers) still relies partly on preservatives or other materials.

Evidence of displacement — D1: works, adoption not proven#

Verified figures (the number is in the quoted sentence and the sentence is on the source page):

• displacement — Global production of modified wood reached approximately 1,608,000 m³ annually, primarily from thermal modification methods. (global, not specified; weak: academia.edu)
• performance — The thermally modified wood market has experienced a 6.8% compound annual growth rate (CAGR) from 2025 to 2034, driven by its chemical-free approach as an alternative to CCA and other toxic preservatives. (global, 2025-2034; weak: marketintelo.com)
• performance — In 2025, thermally modified wood accounted for 57.52% of the modified wood market, while acetylated wood represented 17.04% and other types captured 25.44%. (global, 2025; weak: pmarketresearch.com)
• performance — Global commercial production of modified wood is dominated by thermal modification processes, which produce 1,110,000 m3/year, with acetylation accounting for 120,000 m3/year and furfurylation 45,000 m3/year. (global, not specified; weak: pdfs.semanticscholar.org)

Suppliers — real products and services (from the vendor index)#

Honest finding: the vendor index has no modified-wood producer (only chemical wood-preservative makers match). This is recorded as a supplier gap.

Companies below are active vendors in the vendor index whose own card (profile / official website) shows this product or service — matched 2026-10-05 by keyword and checked by hand against the card text. Being listed is not an endorsement; open each card for evidence, contacts and status.

Update 2026-10-05: the new Europe dataset supplies this product — rows marked Europe below. For the other regions the gap noted above still stands unless a row says otherwise.

Government funding signals#

Public grants for a specific technology are a leading indicator: governments fund what regulators want to replace and what is close to practical adoption. Searched on 2026-09-27 in: EU CORDIS (FP7, Horizon 2020, Horizon Europe), US federal awards (USAspending: USDA NIFA/ARS/APHIS/Forest Service, EPA, DOE, NOAA, USAID; plus NSF and NIH), UK UKRI Gateway to Research, Australian Research Council. Each grant below was reviewed by hand for relevance. China, Brazil and India are covered in the subsection below (publication-acknowledged grants). Not covered: Russia (RSF, FASIE — not reachable from the research environment) and national agencies outside these databases. Amounts are the funder’s contribution as recorded (US NIH/UKRI: per award or fiscal year).

Signal: Moderate. 2 relevant grant(s) · about €2.2M in total · jurisdictions: EU, USA.

China, Brazil, India — national research grants acknowledged in publications#

Chinese, Brazilian and Indian funders have no open grant databases reachable here, so this measures scientific papers published since 2015 that acknowledge national government grants, taken from the grant numbers publishers deposit with Crossref. Only papers whose title contains this article’s key terms are counted (a conservative lower bound; “100+” = search window full). It shows research-funding intensity, not budgets. Funders: China — NSFC, National Key R&D Program, China Agriculture Research System; Brazil — CNPq, CAPES, FAPESP, Embrapa, FAPEMIG; India — DBT, DST, ICAR, SERB, CSIR, BIRAC. Rating per country: Strong ≥50 papers · Moderate 10–49 · Weak 1–9.

Scientific evidence#

• Hill CAS (2006). Wood Modification: Chemical, Thermal and Other Processes. John Wiley & Sons, Chichester.
• Lande S, Westin M, Schneider M (2004). Properties of furfurylated wood. Scandinavian Journal of Forest Research 19 (Suppl. 5): 22–30.
• Rowell RM, Dickerson JP (2014). Acetylation of wood. In: Schultz TP, Goodell B, Nicholas DD (eds) Deterioration and Protection of Sustainable Biomaterials. ACS Symposium Series 1158, American Chemical Society, Washington DC, 301–327.
• Commission Directive 2003/2/EC relating to restrictions on the marketing and use of arsenic (CCA wood preservatives).

Bioeconomy value#

Farm residues (furfuryl alcohol), plantation timber and heat produce long-lived wood products that store carbon and avoid arsenic, chromium and PAH contamination: a core forest-bioeconomy technology, highly relevant for Russian timber.