# ANNEX 4

## WCFSD Forest Classification System

In combining the data sources into one global coverage with four different categories of forest type, the classifications used in the original data sources had to be harmonised into these four categories.

    WCFSD   DESC
    OPTR    Open tropical forest
    OPTE    Open temperate forest
    CLTR    Closed tropical forest
    CLTE    Closed temperate forest

As a general guideline the Tropics of Cancer and Capricorn were used to differentiate tropical from non-tropical forests. Land cover with more than 10% tree crown cover was considered "forest", agreeing with the FAO definitions used for their Global Forest Resources Assessments (FRA). To separate Open from Closed forests a percent tree crown cover of 30% was used as the dividing line between the two. However, very few data sources specified the percent crown cover of the forest patches, so Open and Closed forest was distinguished using the following source category words:

Open Forest in this project included the classifications:

Tree Savanna

Tree Steppe

Open Woodland

Woodland/grassland mosaic

Woodland/scrub mosaic

Forest/grassland mosaic

Forest/scrub mosaic

Tundra with trees

Closed Forest in this project included the classifications:

Forest

Closed forest

Open Forest

Woodland

Dwarf forest

Disturbed forest

Degraded forest

As many of the national maps did not depict Open Forest according to these definitions, the data from the recent U.S.G.S./EROS Data Centre seasonal land cover classification were widely used. This was considered to be the best available global source, even though the datasets have not yet been thoroughly checked through and finalised, and the classes did not carry with them detailed structural or botanical definitions. In some cases expert opinion had to be used to decide whether to include a class or not, overriding the general guidelines for Open or Closed Forest classes listed above. No distinction was made between plantation (man-made) forests and natural ones. Although "disturbed" and "degraded" forests were included in Closed Forest, the Forest and Woodland mosaic classes listed under Open Forest probably contained forests that are degraded and may have some small-scale agricultural activities in them. However, classes that specifically indicated an agricultural element (such as "forest/crop mosaic") were generally excluded from the maps.