Forestry Statistics 2010 - Sources

Sources: Timber

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Background

The Sawmill Survey is an annual survey conducted by the Forestry Commission (in association with the Forest Service) of sawmills in the UK that are believed to use UK-grown logs.

The survey, which previously covered sawmills in Great Britain only, was extended in 2004 to include sawmills in Northern Ireland. Figures for Northern Ireland in earlier years have therefore been estimated, based on responses to the 2004 survey.

The detailed survey has changed over recent years, both in terms of coverage and periodicity. For 1996 and earlier, detailed questionnaires were issued triennially to mills producing at least 1,000 m3 of sawnwood. From 1998 to 2004, the questionnaires were issued on a biennial basis to mills producing at least 5,000 m3 of sawnwood. From 2005, the detailed questionnaires have been issued annually, to mills producing at least 10,000 m3 of sawnwood.

Data collected

2 questionnaires are used for the Sawmill Survey:

  • a detailed questionnaire goes to around 50 mills that have annual production of at least 10,000 m3 of sawnwood, and
  • a short questionnaire is sent to all other mills that are believed to take UK sawlogs (around 200 mills).

Both questionnaires collect information on:

  • the consumption of UK and imported logs,
  • the production of sawnwood,
  • chain of custody certificates and certifed timber,
  • (from the 2006 survey) sales to bioenergy,
  • (from the 2008 survey) sales as firewood and internal use for heat/ energy and
  • (from the 2008 survey) total employment.

In addition, the detailed questionnaire also collects information on:

  • the source of UK logs (England, Wales, Scotland or Northern Ireland),
  • sawnwood product markets,
  • other products and
  • sawmill employment.

Response rates

In 2009, detailed questionnaires were issued to 51 mills, of which 41 responded, giving a response rate of 80%. For the short questionnaire, 81 responses were received from the 168 forms issued, corresponding to a 48% response rate.  This gives an overall response rate of 56%.

Overall, the 122 sawmills responding to the sawmill survey in 2009 are estimated to account for around 87% of total UK sawnwood production.

Sawmill Survey Response Rates (all questionnaires), 2000-2009

Year

Forms issued

Responses received

Response rate

2000

374

193

52%

2001

260

172

66%

2002

288

150

52%

2003

260

143

55%

2004

262

147

56%

2005

257

143

56%

2006

264

161

61%

2007

243

149

61%

2008

227

133

59%

2009 

219

122

56%

Methodology

Each year, figures for non respondents are estimated by rolling forward data from previous years for these mills. For larger mills, these estimates may be modified to take account of advice from the Expert Group on Timber & Trade Statistics.

Time series data for the detailed sawmill survey

From one year to another, some mills may have moved above or below the threshold for inclusion in the detailed sawmill survey.  This may affect the trends over time in tables 2.17a to 2.20a.

The total volume of roundwood consumed and sawnwood and other products produced by sawmills covered by the detailed sawmill survey varies over time, so a change in the percentages shown in tables 2.17a to 2.19a does not necessarily reflect a change in volumes.

Revisions

Results from the Sawmill Survey may be revised between the provisional figures published in the First Release 'UK Wood Production and Trade (provisional figures)' and the final data published in Forestry Facts and Figures and Forestry Statistics to take account of late returns and the results of additional data quality checking procedures.

All the main results (number of mills, consumption, production) are subject to revision annually, as information becomes available about mills opening or closing, or new information becomes available for previous non-respondents. The most common revisions are relatively small downward changes, but this can vary from year to year as special exercises are run to validate the survey population. Information about new mills opening can on occasion cause much larger upward revisions to softwood volumes, as in British Timber Statistics 2003. Results from the survey of larger mills, which provides more detailed information, may be revised to take account of new information for previous non-respondents.

Reporting

Statistics reported for each year are limited to mills that are known to use UK roundwood, but also include any imported logs used by these mills.

Tables for softwood are broken down by country (England, Wales, Scotland, Northern Ireland) and by size of mill. Given the low number of sawmills using UK hardwood, tables for hardwood are presented at a total UK level only.

The number of active mills is presented in tables 2.9 to 2.11.

Longer time series, providing data on numbers of mills and on softwood consumption and production are available from the Timber Statistics web page.  The time series data feature breakdowns by size of mill, by country and by region (in England).

Links to Forestry Statistics 2010

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