Forest

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Logo. Feature : Forest
One example for Feature : Forest
Description
How to describe tree-covered areas like forest or woodland. There are some tagging approaches. Describing the meaning of tags natural=wood and landuse=forest.
Tags

A forest or woodland is a natural or semi-natural area covered by trees, which may or may not be used to produce forestry products such as wood and timber. In English, the terms "wood" and "forest" have overlapping meanings, but are clearly distinct from an orchard, which is an area of trees used to produce food (landuse=orchard).

Different tags are used to map a wood, forest or other area of trees, primarily natural=wood and landuse=forest. There are differences in the way these are used by some OpenStreetMap mappers.

The situation is complicated as different people advocate different, conflicting tagging schemes.

Depending on region there may or may not be difference between areas tagged as natural=wood and landuse=forest. The difference, if any, depends on who mapped the area. As result nearly all data consumers treat both natural=wood and landuse=forest as synonymous tags for a wooded area.

This problem is explained below.

Which tag should be used?

The differences in tagging woodland essentially result from different approaches to document human management and use of woodland areas (excluding orchards, which are consistently tagged with landuse=orchard). The following approaches are advocated by different groups:

Approach 1

Approach 2

Note that visiting location is not enough, checking whatever land is managed for forestry requires more extensive research and many people marking forests are not interested in spending time on tagging distinction between managed and unmanaged forest.

Tag managed=* is very rarely used (less than 6500 instances in database [1])

Approach 3

  • landuse=forest is used for maintained or managed woodland. This approach views most woodland as managed or maintained especially in areas such as Europe.
  • natural=wood is used for ancient or virgin woodland, with no forestry use.

Approach 4

  • wood=yes is used to mark the presence of trees. Use of wood=* is deprecated for indicating vegetation types but wood=yes is still used. It is however fairly uncommon (less than 1000 instances in database [2]).
  • natural=wood is used to mark areas of unmanaged forest. It implies wood=yes
  • landuse=forest is used to mark areas of managed forest. It implies wood=yes

Approach 5

  • landcover=trees is used to mark the presence of trees. It does not imply the use nor origin of the trees. This can be used in combination with other approaches. Note that this tag is rarely used tag for wooded areas (100,000 instances in database [3]) compared to overall use of natural=wood and landuse=forest tags (about 5 million each).

Approach 6

Does not attempt to give meaning to differences between these tags. Typically used during mapping from aerial images, or during casual survey without extensive research of a given forest. Also used by mappers not interested in distinctions discussed above or unaware about them.

Additional tags may be used to clarify purpose, forestry status etc.

Note that this approach is used by nearly all data consumers, including Standard tile layer[1].

Discussion

Advantages of each approach

  • Approach 1
    • Tags appear consistent – having trees on is not a "land use".
    • Does not require the tagger to make a distinction between managed and virgin woodland, which can be near impossible to make even for someone surveying the area.
    • Allows for tagging of areas of commercial forestry which are not currently wooded (landuse=forest + natural=scrub).
    • Is more consistent with tagging of other features such as reservoirs, which are tagged natural=water, along with their land use.
    • This approach is recommended for use in Russia as a result of discussion and further voting in local OSM community.
  • Approach 2
    • Mapping forests does not require the tagger to make a distinction between managed and virgin woodland
    • Information about forest management is stored in a tag separate from natural=wood and landuse=forest
  • Approach 3
    • More commonly used after a bot was used to retag existing woodland this way.
  • Approach 4
    • As for Approach 1
    • Uses only existing tags.
    • Existing tagging largely retains its meaning.
    • Further landuses might be specified to distinguish between forest managed for decorative/leisure use, lumber/pulp production, or ecological improvement.
  • Approach 5
    • Simple. No need to identify use nor origin of the trees
    • Can be used in addition to landuse=forest, landuse=orchard, and natural=wood
  • Approach 6
    • Mapping forests does not require the tagger to make a distinction between managed and virgin woodland

Disadvantages of each approach

  • Approach 1
    • Conflicts with approach 2, 3, 4.
    • Requires the mapper to make a distinction that can be very difficult. People mapping forests are likely to be unable or not interested in making this distinction.
    • Conflicts with widespread interpretation of landuse=forest as marking of forested areas. Potential switch to this tagging scheme would require updates on side of data consumers.
    • Any forest mapped using approach 6 requires resurvey.
  • Approach 2
    • Conflicts with approach 1, 3 and 4
  • Approach 3
    • Requires the mapper to make a distinction that can be very difficult. People mapping forests are likely to be unable or not interested in making this distinction.
    • Conflicts with approach 1, 2, 4.
    • Any forest mapped using approach 6 requires resurvey.
    • Does not distinguish between landuse=forest, natural=wood tagged using this approach and other approaches.
  • Approach 4
    • Uses the wood=* key which has gone out of favor for other purposes.
    • Conflicts with approach 1, 2, 3
    • Any forest mapped using approach 6 requires resurvey.
    • Forest tagged by mapper unable/uninterested in making distinction between managed and unmanaged forest would be ignored by typical data consumers. As result people are unlikely to start using this scheme.
    • Is fairly uncommon.
  • Approach 5
    • landcover=trees is not common (taginfo oct 2019: 100000) and rarely supported by data consumers. As result either original mapper or somebody editing later in a given region will use other approach - instead or in addition to.
    • Does not distinguish between orchards and similar tree plantations used for food (landuse=orchard), even though these are visibly different on aerial imagery and in survey.
  • Approach 6
    • Does not distinguish between landuse=forest, natural=wood. As result it is disliked by people that would prefer these tags to have a different meaning.

General problem with this tagging scheme

When mapping from aerial or satellite images is usually very difficult to determine if a woodland area is used for forestry. This can be difficult even for the observer on the ground. As result, most mappers use landuse=forest and natural=wood fairly arbitrarily.

As result tagging schemes that rely on a particular difference between natural=wood landuse=forest are problematic. For a given area it is complicated to guess which tagging scheme used by the original mapper. It is nearly impossible to do it automatically and there are no known tools for doing this. As result other mappers and data consumers are unable to use data that was intended to be added by selecting natural=wood or landuse=forest.

Historical development

The tag natural=wood was first used in England in the early days of OpenStreetMap, before mapping had spread to other countries. There it was used to map a wood or a forest in the countryside. (At the time, very small patches of trees in parks or urban areas were not yet mapped). The tag landuse=forest was added to areas that were clearly used for managed forestry - usually plantations of conifer trees which were planted to produce timber and lumber. These are distinct from the semi-natural broadleaf woodlands in England.

However, when mappers in other countries wanted to map a named "forest", they often used landuse=forest. Other mappers considered that woods are not really "natural" when they are managed by humans, so used landuse=forest for all kinds of woodland.

In other regions, especially in the sub-artic and the tropics, there is no clear distinction between woodland areas which are actively managed for timber and lumber production, and areas of woodland which are lightly used by humans. In these countries it is usually not possible for a visiting mapper to determine the level of human management of a particular area of trees.

Over time it became popular to map small areas of trees within residential areas, university campuses, urban parks, and other features. Both landuse=forest and natural=wood were sometimes adopted for this purpose by different mappers, which expanded their meaning from "a forest or wood" to "an area covered by trees (which is not an orchard)". Some use landuse=forest because urban trees are "managed", others use natural=wood because these areas not used for forestry.

Additional tags

  • name=* - name of the forest
  • leaf_type=broadleaved/needleleaved/mixed - describes the type of leaves.
  • leaf_cycle=deciduous/evergreen/mixed - describes the phenology of leaves.
  • managed=yes/no - whether a woodland area is actively managed
  • produce=* - to describe the produce of a woodland/forestry area (e.g. produce=wood, produce=timber, produce=cork). Also see crop=* and trees=*, used for landuse=orchard.

Rendering

For a given area it is impossible to guess what kind of tagging scheme was used by the original mapper, so in practice both natural=wood and landuse=forest are typically interpreted as "area covered by trees".

On maps forests are typically a green area. When leaf_type=* is set one may show little broad leaved or coniferous (or both) icons.

Possible rendering of woodland
Tag Rendering Comment Pictures
leaf_type=broadleaved Wood deciduous.png Broadleaved woodland. WaldAlfeld.jpg Aerial view of the Amazon Rainforest.jpg
leaf_type=needleleaved Wood coniferous.png Needleleaved woodland. Swiss National Park 131.JPG Pinus canariensis (Barlovento) 06 ies.jpg
leaf_type=mixed Wood mixed.png Mixed woodland. Mixed forest-Poland spring.jpg 09272008 BrightonUT.JPG

Possible Tagging Mistakes

If you know places with this tag, verify if it could be tagged with another tag.
Automated edits are strongly discouraged unless you really know what you are doing!
If you know places with this tag, verify if it could be tagged with another tag.
Automated edits are strongly discouraged unless you really know what you are doing!

See also

Related OSM projects

Wiki for all environment and natural tags and projects Environmental OSM

References