Content
About the statistics
Definitions
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Name and topic
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Name: Forestry, sample survey of agriculture and forestry (discontinued)
Topic: Agriculture, forestry, hunting and fishing
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Responsible division
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Division for Primary Industry Statistics
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Definitions of the main concepts and variables
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Agricultural and forestry property
Property that is used for or could be used for agriculture and/or forestry. All agricultural/forestry area belonging to the same owner within a municipality is regarded as one property, irrespective of the number of cadastral units.
Productive forest area
Forest area that under favourable stand conditions has an annual yield capacity per hectare of at least 1 cubic metre of wood including bark.
Forest property
Property with at least 25 decares of productive forest area.
Supplementary industry: The Sample Survey of Forestry defines supplementary industries as industries that utilise the properties' area and resources in forest and other outfields.Gross income: The sum of all incomes excluded value added tax, and not deducted any costs.
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Standard classifications
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Not relevant
Administrative information
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Regional level
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County
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Frequency and timeliness
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Annual.
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International reporting
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Not relevant
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Microdata
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Edited microdata are stored in Statistics Norway.
Background
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Background and purpose
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The purpose of the Survey of Forestry is to obtain relevant data not found in administrative data systems, and to obtain data for units not covered by administrative systems.
The Survey of Forestry is one of several data sources which together shall complete a picture of the agricultural and forest industry in Norway. The themes in the survey vary from year to year. Questions about labour force, debt, investments, fixed assets, extended forest survey and environmental themes like about tilling and fertilizing practices appear frequently.
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Users and applications
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Data from the survey are used by professional organizations, the Ministry of Agriculture and Food, the Ministry of Environment, various research institutions such as the Norwegian Agricultural Economics Research Institute and the Division for Environmental Statistics at Statistics Norway.
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Coherence with other statistics
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Results from the Sample survey of Forestry 2008 may be compared with official statistics based on registers such as the statistics on Commercial roundwood removals and Silviculture.
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Legal authority
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Statistics Act §§2-1, 2-2, 2-3.
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EEA reference
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Not relevant
Production
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Population
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The population is holdings and properties registered in the administrative Farm Register of the Norwegian Agricultural Authority, and covers all units that meet one or more minimum conditions related to areas or number of livestock. Examples of such conditions are that a holding must have at least 5 decares of agricultural area in use and a forest property must have at least 100 decares of productive forest area.
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Data sources and sampling
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The majority of the data comes directly from respondents who fill in a form for the annual survey. The Farm Register provides basic information on the size of the agricultural and forest areas and persons associated with the property/holding as owner/holder.
Each year a sample is drawn from the Farm Register for the Survey of Forestry. In 2008 the sample included 9.418 forest properties, stratified by the size of the productive forest area and county.
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Collection of data, editing and estimations
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Forms are sent to the properties/holdings included in the survey. The owner or holder provides the data. The municipal agricultural administration plays an important role in the collection of forms and also roughly inspects the forms before they are forwarded to Statistics Norway.
A number of controls and corrections are done to ensure consistency both within a single form and between forms and available register information. During this work, the local agriculture offices are contacted to clear up various lacks and ambiguities.
The Sample Survey of Forestry 2008 is based on a classification of the population of properties with at least 100 decares productive forest area in 8 size classes of productive forest area and 18 counties (Oslo and Akershus together) - totally 144strata. In each stratum a drawing probability (percentage) is decided. The drawing per cent is increased in strata with few properties. On this basis an extrapolation factor is created for each property in the sample. This factor is like the ratio between the number of properties in the population and in the samples in each stratum.
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Confidentiality
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Any statistics based on three respondents or less are not published.
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Comparability over time and space
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In the years 1971-1989 Statistics Norway worked out separate sample surveys of forestry. The sample used in the period 1971-1979 was drawn from the Census of Forestry 1967. The sample used in the years 1980-1989 was drawn from the Census of Agriculture and Forestry 1979. The Census of Agriculture and Forestry 1979 was the first complete census conducted in Norway that included both agriculture and forestry.
From 1990 a yearly sample survey of agriculture and forestry has been conducted. The sample used for the period 1990 - 1998 was drawn from the Census of Agriculture and Forestry 1989. As from 2000 the sample is drawn from the Farm Register of the Norwegian Agricultural Authority.
Accuracy and reliability
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Sources of error and uncertainty
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Primary data are obtained from the forms filled in by the respondents. They may contain errors made by the individual respondents when he or she filled in the form. A number of errors are discovered and corrected during the editing process at Statistics Norway. Errors may also occur during the data processing. Extensive work has been carried out to reduce these errors as much as possible.
Non-response in the survey is mainly due to that individual respondents refuse to answer the questionnaire. In the Sample survey of Forestry 2004 the non-response rate due to refusal was 6,5 per cent.
Another type of non-response is that a property or holding has been merged with another property/holding and is no longer an independent unit.All sample surveys will be hampered by uncertainty. Generally, the fewer the observations, the more uncertain the results. Groups based on few observations will be particularly sensitive to extreme values, i.e. values that deviate considerably from the average. Such extreme values are consequently assigned a weight equal to 1, so that they only represent themselves in the statistics.
In the Sample Survey of Forestry 2008 all types of forest properties are included. To provide a better representation in certain counties with few properties a higher percentage of holdings is selected.The quality of the register from which the sample is drawn has crucial impact on the quality of the final result. During the editing process in Statistics Norway it was discovered that the Farm Register was not completely updated regarding fusion of properties.