The price of robinia explained – why it is worth what it costs

Ferdinand Terlinden

1 day ago

7 min read

Robinia series · Pricing and buying guide

"How much does it cost?" – the real answer begins 25 years before your quote.

It is the most searched question about robinia (Robinia pseudoacacia) – also known as black locust, and often sold as acacia – and the least well answered: you find prices without explanation, or explanations without prices. Here are both – the market's orders of magnitude and, above all, what makes up the price of a timber that lasts thirty years.

None of the figures on this page is a price list: prices move with species, sections and seasons. But the proportions are stable – and they are what help you decide.

25 to 30 years

the age of a robinia tree at harvest: a stake is also paid for in years of patience

Dense robinia forest in Romania, closely spaced slow-grown trees harvested at 25-30 years — Dense robinia stand: 25 to 30 years of slow growth before the first sawable log.

What makes up the price of robinia

Time. A robinia tree takes 25 to 30 years to become harvestable, in dense stands that are never thinned – that is what makes its timber hard, and it is time tied up.

Sorting. The tree rarely grows straight. On a felling site, only sufficiently straight logs go for sawing; the rest is downgraded to wood fuel. This material yield, among the lowest of all commercial species, is reflected in every board sold.

Forwarder loaded with crooked, thin robinia (acacia) stems destined for firewood on a felling site — On the felling site, the forwarder loads crooked and thin stems separately: thirty cubic metres out of a hundred leave the plot as firewood before they have even seen the sawmill.

Removing the sapwood. Durability requires the sapwood – the pale, non-durable ring – to be removed. On logs of 15 to 30 cm, this removes still more material: a "sapwood-free" stake costs what the centimetres taken off cost.

Labour. Very hard timber = slow sawing, tools that wear, heavy handling (780-820 kg/m³ fresh from the sawmill). And processed products – finger-jointed, planed, sanded – add drying to 12 %, certified gluing and skilled labour.

Traceability. APV marking, SUMAL, FSC, the EUDR: Romanian traceability and certifications carry a real administrative cost – and that is also what you are buying: proof of origin.

Grapple loader sorting robinia logs by grade in the log yard of the Teiu sawmill — Sorting in the log yard: every log is graded on arrival, and those that don't make the grade join the firewood pile – twenty cubic metres out of a hundred.

From tree to product: where do the 100 m³ of a plot go?

Material yield is the most concrete explanation of the price, and it is the one nobody gives. Here is the real journey of 100 m³ of standing robinia, as we measure it on our own felling sites.

Infographic of robinia material yield – 100 m³ standing, 70 m³ loaded for the sawmill, 50 m³ into production, about 25 m³ of finished product, and the sawing loss by product — From plot to finished product: out of 100 m³ of standing robinia, about 25 m³ comes out as product sold. Everything else is put to use, but as wood fuel – at a very different price.

Stage	Volume	What becomes of it
Standing, in the plot	100 m³	the stand harvested
Sorted on the felling site	− 30 m³	crowns, crooked and thin stems: firewood, used locally
Loaded for the sawmill	70 m³	what goes by road to our sawmill in Teiu, Hunedoara County (Romania)
Rejected at grading	− 20 m³	logs that don't make the grade: firewood
Into production	50 m³	what actually goes into sawing
Processing losses	− 30 % to − 70 %	bark, removed sapwood, slabs, edgings and offcuts: wood chips and wood fuel
Finished product sold	≈ 25 m³	about a quarter of the standing tree

In other words: out of a hundred cubic metres of standing tree, about twenty-five come out as finished product sold – a quarter. The rest is not lost, but its price changes – crowns, crooked stems, downgraded logs, slabs and offcuts go off as firewood and wood chips. It is this proportion, far more than the sawmill's hourly cost, that widens the gap with plantation pine cut in volume.

The processing loss is not the same for every product, and it can double from one to another. It is around 30 % for products that do not go through sawing and keep the round shape of the tree: a round stake needs only debarking, a sanded post debarking followed by removal of the sapwood, the pale ring just under the bark. Crooked timber and timber with rot are also rejected here and go off as firewood. But there are no slabs or edgings: nothing is recut to make the piece straight.

It climbs to as much as 70 % on sawn products – vine stakes, decking boards, small sections. The reason lies in the resource: Romania's robinia forests are dense and the trees there stay small in diameter. And sawing yield drops as the log gets smaller, since you have to fit a square inside a circle: whatever lies outside goes as slabs, the saw kerf takes its share, and internal defects finish the job. A round stake and a decking board therefore do not start from the same log volume, and that already accounts for a good part of the price difference between the two.

Two things can be read on a log before the first saw cut. First, the diameter: our logs run between 15 and 30 cm, and geometry is merciless – the largest square that fits inside a circle occupies only 64 % of its cross-section, i.e. 17 to 18 cm a side for a 25 cm log. A third goes as slabs before defects have even been mentioned. Then the defects, and robinia is not short of them: star shake, pockets of rot at the centre of the oldest logs, black knots left by the lower branches, bark inclusions, and above all cross-sections that are not round but lobed. A fluted log measuring 30 cm on the outside yields no more than a round 22 cm log. And these defects are discovered at sawing, not at grading: that is where the real yield of a batch is decided.

Small-diameter robinia (acacia) logs on a sawmill infeed table, star shake and timber defects visible on the ends — Robinia logs on the sawmill infeed table: they show the two limits of sawing – modest diameters, and logs that are neither perfectly round nor always sound (star shake, rot pocket, black knots, lobed cross-sections).

Market orders of magnitude (2026)

Product	Order of magnitude	Competitor benchmark
Robinia decking boards	≈ half the price of ipe	Ipe 140-180 · composite 60-140 · pine 25-45 (€/m²)
Robinia stake	Unit price by section	Sweet chestnut 15-40 % cheaper · pressure-treated pine cheaper to buy
Cost per year of service	~30-year service life	Pressure-treated pine: ~10 years, replacements included

These amounts are market observations, not our prices – every quote depends on sections, lengths and quantities. The proportion to remember: robinia costs two to three times the price of treated softwood to buy, and about half the price of a tropical hardwood – for durability in the same use class as the latter.

The right calculation: divide by the years

A purchase price compares badly between a timber that lasts 10 years and one that lasts 30. Bring everything back to the year of service: the most expensive stake in the shop often becomes the cheapest in the field, once the two replacements avoided are counted – and the labour that goes with them. The detail of this calculation is in our comparison with pressure-treated pine.

Why long straight lengths cost more

A long, straight, defect-free piece of robinia is statistically rare – the tree is crooked. The greater the length requested, the more the proportion of logs able to supply it collapses, and the price follows. This is exactly the problem finger-jointing solves: short pieces with their defects cut out, glued into stable profiles up to 6 m, at the price of an industrial process rather than the price of rarity.

Porch in solid robinia beams 15x15 cm, large straight sections that are rare and more expensive — Porch frame in solid robinia 15 × 15 cm: large, straight, defect-free pieces are the rarest in the harvest.

How to make the most of your budget

Describe the use rather than the product: the sawmill will then choose the most economical section, grade and length that will do the job – a joist does not need the visible face of a decking board, a cladding board does not need the section of a purlin. Mixed lengths, AB grades and full pallets also bring down the price per metre without affecting durability: that lies in the heartwood, not in the looks.

Key points

· The price of robinia = 25-30 years of growth + strict sorting (low material yield) + sapwood removal + a hard timber to work + traceability.

· Material yield: out of 100 m³ standing, 30 stay in the forest as wood fuel, 20 fall out at grading and processing takes another 30 to 70 % – about 25 m³ of product sold at the end, a quarter of the tree.

· Orders of magnitude for 2026: robinia decking boards sit at around half the price of ipe and two to three times that of pressure-treated pine; a sweet chestnut stake remains 15 to 40 % cheaper.

· Compare the cost per year of service: 30 years against 10, replacements and labour included.

· Long straight lengths = rare, therefore expensive; finger-jointing replaces rarity with a process.

· To pay less: describe the use, accept mixed lengths and AB grade – durability loses nothing.

Frequently asked questions

What makes up the price of a robinia stake?

Five things: 25 to 30 years of growth before harvest; strict sorting in which only straight logs go for sawing; removal of the sapwood, essential for durability; a very hard timber, slow to saw and heavy to handle; and traceability (APV, SUMAL, FSC, the EUDR). You are not paying for a piece of wood: you are paying for thirty years of proven service. Material yield sums it all up: out of 100 m³ of standing tree, about a quarter comes out as finished product, the rest going to wood fuel and wood chips.

How much does robinia decking cost per square metre?

We do not publish a price per square metre, and that is deliberate: the price of a robinia deck can double depending on whether it uses solid or finger-jointed boards, is supplied direct or through a distributor, in fixed or mixed lengths, and on the quantity. An isolated figure on a web page commits nobody and misleads. What is stable, on the other hand, is the positioning: for the boards supplied, robinia sits at around half the price of ipe, above entry-level composite, and at two to three times the price of treated pine that does not play in the same durability league. Add the substructure (joists) and installation, and ask for a quote on your actual sections.

Why are long straight lengths rare and more expensive?

Because robinia is a crooked tree: logs capable of yielding 4, 5 or 6 metres straight and free of defects are statistically rare, and their price reflects that rarity. That is the whole point of our finger-jointed profiles: short pieces with their defects cut out, joined into stable lengths up to 6 m – the process replaces rarity.

How can you bring the bill down without sacrificing durability?

Describe the use to the sawmill rather than ordering a specific product: just the section needed, AB grade where appearance matters little, mixed lengths, full pallets. Robinia's durability lies in its heartwood – not in perfect straightness or a knot-free face – and it is appearance that costs, rarely longevity.