The forest coverages for the regions were in general made up from a number of different regional and national sources, by region and by country, as outlined in Appendix 1. Countries excluded from the study are found in Appendix 3. The data sets were examined one by one and the data harmonised into a general forest classification which was devised for this study, consisting of 15 different tropical forest types and 11 different non-tropical ones (Table 1). The classification was designed to reflect characteristics of the forests that would be of conservation importance, for example, whether the forest is tropical or non-tropical, whether it is a plantation of exotic species, or whether it is a degraded natural forest type. Some parts of this study refer to"natural undisturbed forest types", which include all categories except exotic species plantations, native species plantations and disturbed natural forest. Not wishing to exclude much of the important areas that support trees which are sparsely distributed, a category for sparse trees and parkland was included. This agrees with the definition of"forest" used by FAO in their Forest Resources Assessments. Apart from this criterion for the limits of tree cover for"forest", there was no particular height limit used, just that the trees had to be mainly phanerophytes (single-trunked individuals, as most trees) and not chamaephytes (multi-stemmed individuals, as most shrubs).

The forest type categories were defined as follows, and these definitions were used to enable the translation from national classification systems to this global one. Because many of the national forest maps did not have either height or density criteria stated in their legends or keys, certain assumptions had to be made when carrying out the translation of the classifications. The forest type on the original source map was translated into the categories used in this study by comparing whatever information in the source map with the definitions for this study and choosing the closest one.

The split between"tropical" and"non-tropical" was made by including all those forests that were located between the tropics of cancer and capricorn in the tropical category, and assigning all other forests to"non-tropical". Some forest maps depicting montane forests within the tropics name them"temperate", but in the translation to the system used here these were registered as tropical. In all graphs and tables the letter"T" after a forest type name indicates that it is tropical,"N" similarly denoting non-tropical.

Natural forests with > 30% canopy cover, composed of species of mangrove tree, generally along coasts in or near brackish or salt water.

Natural forests with > 30% canopy cover, below 1200m altitude, composed of trees with any mixture of leaf type and seasonality, but in which the predominant environmental characteristic is a waterlogged soil.

Natural forests with > 30% canopy cover, below 1200m altitude that display little or no seasonality, the canopy being >75% evergreen broadleaf.

Natural forests with > 30% canopy cover, below 1200m altitude in which between 50-75% of the canopy is evergreen, > 75% are broadleaves, and the trees display seasonality of flowering and fruiting.

Natural forests with > 30% canopy cover, below 1200m altitude in which between 50-100% of the canopy is deciduous and broadleaves predominate (> 75% of canopy cover).

Natural forests with > 30% canopy cover, below 1200m altitude, in which the canopy is mainly composed of sclerophyllous broadleaves and is > 75% evergreen.

Natural forests with > 30% canopy cover, below 1200m altitude, in which the canopy is mainly composed of deciduous trees with thorns and succulent phanerophytes with thorns may be frequent.

Natural forest with > 30% canopy cover, below 1200m altitude, in which the canopy is predominantly (> 75%) needleleaf.

Natural forests with > 30% canopy cover, below 1200m altitude, in which the canopy is composed of a more or less even mixture of needleleaf and broadleaf crowns (between 50:50% and 25:75%).

Natural forests with > 30% canopy cover, between 1200-1800m altitude, with any seasonality regime and leaf type mixture.

Natural forests with > 30% canopy cover, above 1800m altitude, with any seasonality regime and leaf type mixture.

Natural forests in which the tree canopy cover is between 10-30%, such as in the savannah regions of the world. Trees of any type (e.g., needleleaf, broadleaf, palms).

Any forest type above that has in its interior significant areas of disturbance by people, including clearing, felling for wood extraction, anthropogenic fires, road construction, etc.

Intensively managed forests with > 30% canopy cover, which have been planted by people with species not naturally occurring in that country.

Intensively managed forests with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.

Natural forests with > 30% canopy cover, composed of trees with any mixture of leaf type and seasonality, but in which the predominant environmental characteristic is a waterlogged soil.

Natural forests with > 30% canopy cover, in which > 75% of the canopy is deciduous and broadleaves predominate (> 75% of canopy cover).

Natural forest with > 30% canopy cover, in which the canopy is mainly composed of sclerophyllous broadleaves and is > 75% evergreen.

Natural forest with > 30% canopy cover, in which the canopy is predominantly (> 75%) needleleaf and evergreen.

Natural forests with > 30% canopy cover, in which the canopy is predominantly (> 75%) needleleaf and deciduous.

Natural forest with > 30% canopy cover, in which the canopy is composed of a more or less even mixture of needleleaf and broadleaf crowns (between 50:50% and 25:75%).

Natural forests with > 30% canopy cover, the canopy being > 75% evergreen and broadleaf.

Natural forests in which the tree canopy cover is between 10-30%, such as in the steppe regions of the world. Trees of any type (e.g., needleleaf, broadleaf, palms).

Any forest type above that has in its interior significant areas of disturbance by people, including clearing, felling for wood extraction, anthropogenic fires, road construction, etc.

Intensively managed forests with > 30% canopy cover, which have been planted by people with species not naturally occurring in that country.

Intensively managed forests with > 30% canopy cover, which have been planted by people with species that occur naturally in that country.