Statistical processing

Source data

The accounts are based on a number of sources:

• The Danish National Forest Inventory which is produced and annually published by the Department of Geosciences and Natural Resource Management, University of Copenhagen.
• The Danish reporting on forest land under Kyoto (LULUCF). This is available at UNFCCC and the European Environment Agency.
• The statistics on felling of wood in the Danish forests, published by Statistics Denmark. This is documented here.
• Market prices of timber products, collected from the Danish Forest Association.

Frequency of data collection

The source data are collected annually.

Data collection

No primary data collection takes place for the forest accounts. All sources are existing statistics or data collected for other purposes. Data collection therefore takes place primarily by collecting reports published on the websites of the relevant organizations. For information on the data collection for these sources, please see the documentation provided in the section on 'Source data'.

Data validation

When the forest accounts are compiled, data from the different sources are combined and thus compared. This leads to a 'plausibility control' across the different sources. The approach consists in preserving the original data as far as possible for the physical stocks. In particular, the growing stock for each year, as published in the National Forest Inventory, is used as a fixed reference point around which other sources are aligned.

Data compilation

The accounts for the forest area build on the Danish reporting of forest land under the Kyoto Protocol. As part of this reporting, a matrix for changes in land cover is created (LULUCF). The accounts for the forest area are produced as a simple extract of the relevant cells from this reporting (concerning the national totals). The regional distribution is based on the National Forest Inventory.

The accounts for the growing stock integrate several sources and contain both a physical part and a monetary one.

The physical accounts for the growing stock are calculated first. Measurements of the growing stock from the National Forest Inventory are used as a starting point for the closing stock at the end of the year - and thus as opening stock at the beginning of the following year. The net increment is the difference between opening and closing stocks. Data on felling is obtained from the statistics on felling of wood in the Danish forests and is adjusted to account for mortality and other types of losses (incl. underreported felling). Gross increment is then calculated as net increment plus felling and other reductions in stock. The regional distribution of the physical accounts for the growing stock is obtained from the National Forest Inventory. All parts of the physical accounts for the growing stock are compiled not only on a national level, but also for the regions. Corrections are made for reductions in stock if the calculation of the physical accounts for the growing stock leads to a negative gross increment, which by definition is not possible.

The economic valuation of the growing stock is based on the physical accounts using the so-called 'stumpage value' method. This is a simplified net present value method where the value of the stock is obtained by multiplying the current volume of standing timber by its stumpage price (i.e. the price a forest owner can get for the right to fell trees that are in the forest), assuming the rate of discount is equal to the natural growth rate. The stumpage prices are estimated from road side market prices of different timber products, deducting costs of felling and transport (data on prices and costs is obtained from the Danish Forest Association). Value calculations are done separately for beech, oak, other broadleaves and conifers. For the most recent year, projected price data is used. When price data becomes final in the context of next year's publication, this year will therefore be revised.

When valuing the growing stock, the value of the growing stock found in forests that are protected against felling (timber production) is set to DKK 0. The share of the growing stock that is unavailable for timber production is estimated based on data on forest conservation from the National Forest Inventory, and is subject to a certain degree of uncertainty.

In addition, an assumption of losses during tree felling is used in the valuation, which is at 20 percent from the start of the data series until 2017 and then decreases by 2 percent each year (to 12 percent in 2021). These losses during tree felling are valued at DKK 0. This is highly uncertain and there is a lack of solid data on this.

Adjustment

There are no corrections other than those described under data validation and data compilation.