Methodology

Start with the evidence

The evidence register shows the latest successfully retrieved version of each identified source record. Rechecking an offer does not create another observation. Raw history is retained. A price list, an asking price and a completed sale are labelled separately; none is silently treated as another.

First observed and last checked describe our retrievals. Published, valid-from and sale dates describe what the source actually states. A recently checked offer is not proof of current stock or a completed sale. Missing dates, dimensions or botanical identity stay unknown.

Original quotes require permission to republish raw data. Any delivered-equivalent amount is separately labelled as an estimate. See sources and attribution for the published source register.

Useful references, even when the source is general

Forest authorities often publish a general price for oak, beech or mixed timber without complete dimensions or grading details. That price can still be useful. Price referencespreserve what the source actually says, alongside its original unit, tax treatment and dates. Missing details are labelled as not stated; they do not make the quotation disappear.

One source can provide a published reference. With multiple quoted values, we show the observed price range and source count. This is the range in those records, not a guaranteed market range or a valuation of a particular piece. No minimum of three suppliers or complete specification is required to display useful evidence.

What we keep separate

Asking prices, starting auction prices, achieved sales and published averages answer different questions and stay separate. An unclassified reported price is labelled as such. Index points and modelled values cannot become observed monetary prices.

We also separate product form, region, market tier, original unit, currency and stated VAT treatment. A price per piece is not converted into a cubic-metre price without evidence of volume. Tax treatment that is not stated stays unknown; a default in an old parser is not evidence that a source excluded VAT.

Stated sizes, grades and drying details stay with the reference and separate it from differently specified material. Where both sources omit those details, that does not establish that the materials are equivalent. General references are labelled accordingly. A generic wood name is not silently expanded into an exact botanical species.

Repeated checks and dates

A repeat check of the same source record does not create another quote. The newest successful version replaces the old one. Source records are not necessarily individual transactions: one price-list row can cover a broad assortment, and a published average can describe many sales. Counts describe recorded references, not how much wood sold.

Old or undated price lists remain inspectable with their dates and limitations. Last checked tells you when we read the page, not when the price was set. A fresh check cannot make an old sale recent or prove that a listing is still available. Future-dated achieved sales are inconsistent and do not qualify as completed-sale references.

Source feeds are not necessarily independent sellers. Known common ownership can be recorded; where independence is not established, the source count is not described as independent market coverage. Follow a reference to see its underlying source records.

Legacy index: broader coverage, weaker comparability

The existing home-page explorer and earlier index endpoints remain legacy aggregates. They use normalized rows and can count repeated retrievals. Their observation count is not a count of independent offers or transactions. Dimensions, drying and grading are not controlled within those aggregates. Latest results separate market tiers (market_tier); the legacy 30-day grouping does not.

Legacy normalization strips a configured VAT rate, converts currency using an exchange-rate date, converts supported units and may apply fixed transport uplifts. Stacked-volume factors and delivery uplifts are estimates. These normalized amounts do not become original source quotes in V2. The legacy confidence score is a provider heuristic, not a calibrated probability that a price is correct.

Legacy P10, median and P90 describe the included rows. Their current five-row gate does not establish independent-source coverage. A broad range for walnut should not be read as the value of your particular slab. Historical records without stable source identities are not automatically promoted into the new evidence register.

Using a reference

Start with the species or source label and material form. Check whether the number is a seller offer, a starting price or a completed sale, then its unit, tax treatment and dates. For a particular slab, width, thickness, drying, figure and defects can make the general reference unsuitable. The original source is linked so you can see exactly what supports the number.

The species directory also includes woods without price coverage. Missing price evidence does not mean the wood has no value. Database errors are shown as unavailable, separately from genuinely missing coverage.

License + attribution

You may republish derived numbers from this index with attribution to korena.eu/timber-index and a link back. Where a source’s license requires per-source attribution (e.g. some official price lists), the source-drawer on a row will tell you which attribution text to use.

The full technical specification — schema, queue topology, provider lifecycle, normalization details — is in the timber-index repository on GitLab.