Forests cover 30 percent of the total land area and include some of the most diverse ecosystems on Earth. Yet we currently loose an estimated 200km2 of forests a day. At the same time, the net loss of forest area is not in itself sufficient to describe land-use dynamics that include both loss of forests due to deforestation and natural disasters and gains in forest area from planting or natural expansion. The rates of deforestation and of forest degradation are therefore crucial to better understand and address recent trends in the status of forest biological diversity.

This indicator consists of two different indicators, one of which is closely related to the indicator on extent of forests and changes over time, the other refers to the condition of existing forests. Global assessments of the world’s forests are currently carried out at 5 year intervals by the Food and Agriculture Organization of the United Nations (FAO) where information is collected on this indicator. The latest Global Forest Resources Assessment was completed in 2005 (FRA 2005) and the results of the next assessment is due in 2010. As part of the Global Forest Resources Assessment 2010 (FRA 2010), countries have been asked to provide information of their area of forest (and on the area of other wooded land) for 1990, 2000, 2005 and 2010 (forecast). Since large-scale afforestation and natural expansion of forests do not take place in most tropical countries, the net loss of forest can, with some caution, be used as a proxy for the rate of deforestation in these countries until better information becomes available. Efforts are currently underway to obtain comparable data on rates of deforestation at regional, biome and global levels (see Future developments below).

No comparable information is currently available on the rate of forest degradation or the area of degraded forest. However, information does exist on some elements of forest degradation notably the area of forest adversely affected by pests, diseases and forest fire, the area of forest classified according to level of disturbance/modification (primary forests, modified natural forests, planted forests etc.) and on stocking levels per unit area.

Degradation can be assessed at different scales. The current focus is on developing a set of indicators which are adapted to both the scale and to the desired element of forest degradation. Based on the outcome of the current study, the feasibility of developing a composite degradation index will be explored.

Information on rates of deforestation will be generated at global, biome and regional levels, but the methodology developed can equally be applied at national levels.

Given the lack of a common definition of forest degradation, no comparable data set on this variable is currently available.

Information on the extent of forests and the net change in forest are is available for most of the countries, but few countries currently can provide information on the rate of deforestation. Attempts at assessing the rate of deforestation have thus been limited to regional or global levels rather than national levels and the sum of net loss of forest area used as a proxy for the deforestation rate at the global level until better data becomes available.

Source: FAO, 2006

Source: FAO, 2006

Total forest area continues to decrease, but the rate of net loss is slowing
Deforestation, mainly conversion of forests to agricultural land, continues at an alarmingly high rate – about 13 million hectares per year. At the same time, forest planting, landscape restoration and natural expansion of forests have significantly reduced the net loss of forest area. Net change in forest area in the period 2000–2005 is estimated at -7.3 million hectares per year (an area about the size of Sierra Leone or Panama), down from -8.9 million hectares per year in the period 1990–2000.

South America suffered the largest net loss of forests from 2000 to 2005 – about 4.3 million hectares per year – followed by Africa, which lost 4.0 million hectares annually. North and Central America and Oceania each had a net loss of about 350 000 ha, while Asia, which had a net loss of some 800 000 ha per year in the 1990s, reported a net gain of 1 million hectares per year between 2000 and 2005, primarily as a result of large-scale afforestation reported by China. Forest areas in Europe continued to expand, although at a slower rate than in the 1990s.

Countries have been asked, as part of a special study for FRA 2010, to provide information on existing definitions of forest degradation and on methodologies for assessing and monitoring trends in the area of degraded forests where these exist. A technical meeting on the topic is planned for September 2009.

Data on rates of deforestation at global, biome and regional levels will be based on interpretation of 30 m resolution Landsat imagery from 1975 (quality permitting), 1990, 2000 and 2005 as part of the FRA 2010 remote Sensing Survey. The methodology includes extraction of samples of 10 km by 10 km at each intersection of latitude and longitude for regular measurement of the extent of forest and other types of land use and changes over time. The information collected from these plots will be statistically blown up to biome, regional and global levels. Countries will be fully involved in the interpretation of the Landsat data and the validation of the global maps.

Final results of the global remote sensing survey of forests are expected in 2011.