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Desertification Indicator System for Mediterranean Europe


1. Definition

Name

DEFORESTED AREA

Brief definition

Total deforested surface annually as a percentage of the total land surface

Unit of measure

%

Spatial scale

 

Temporal scale

Annual

2. Position within the logical framework DPSIR

Type of Indicator

Driving Force/State

3. Target and political pertinence

Objective

The indicator contributes to quantification of deforestation in a defined area.

Importance with respect to desertification

Deforestation may have catastrophic global effects. Many studies showed that the variation in runoff and sediment yields in drainage basins is attributed to vegetation cover and land use management changes (Douglas, 1969; Reed, 1971; Williams and Reed, 1972; Patton and Schumm, 1975; Newson, 1985; Bryan and Campbell, 1986). On the other hand, it has been demonstrated that in a wide range of environments both runoff and sediment loss decrease exponentially as the percentage of vegetation cover increases (Elwell and Stocking, 1976; Lee and Skogerboe, 1985; Francis and Thornes, 1990). A piece of land is considered desertified when the biomass productivity drops below a certain threshold value. A value of 40% (Thornes, 1988) vegetative cover is considered critical below which accelerated erosion dominates on sloping land. This threshold may be modified for different types of vegetation, rain intensity and land attributes. This however confirms that degradation begins only when a large portion of the land's surface is denuded, and then it proceeds with an accelerated mode, that cannot be arrested by inherent land resistance alone.

International Conventions and agreements

The UNCCD recognised the particular conditions of the Mediterranean affecting desertification processes. The extensive forest coverage losses are due to different causes (deforestation, frequent wildfires, intensive grazing etc) (Convention text as of September 1994 and as of September 2001).

Secondary objectives of the indicator

The deforested area is an indicator of the impact due to loss of forest surface. Information about desertification can help in addressing political measures. Recognition of the loss of cover vegetation in a specific area can be used to organise efficient control and indirectly reduce desertification.

4. Methodological description and basic definitions

Definitions and basic concepts

Data are available for forested areas for different periods and territory levels (FAO; EUROSTAT, ISTAT, CFS). Detailed multi-temporal analyses of satellite data show that deforestation is a highly dynamic process of clearing, abandonment and re-clearing, and that the rates at which land is cleared or abandoned are related to the land use and management system the forest farmers employ. Scientists use a combination of satellite-based earth observation and intensive field data collection to estimate deforestation process on a definite territory.

Benchmarks Indication of the values/ranges of value

class I - score 1: <1.5 % of total deforested surface/total territorial surface/ per year = low incidence

class II - score 1.33: 1.50 - <2.5 % of total deforested surface/total territorial surface/ per year = moderate incidence

class III - score 1.66: 2.5 - <3.5 % of total deforested surface/total territorial surface/ per year = high incidence

class IV - score 2: >= 3.5 % of total deforested surface/total territorial surface/ per year = extreme incidence

Methods of measurement

Ratio between total deforested surface and the total land surface.

Limits of the indicator

One limit of the indicator is the difficulty in finding statistic forest data and homogeneous data on deforested areas for different European countries, at a municipality level. A secondary limit is the lack of a standardised definition for forest.

Linkages with other indicators

Forest fragmentation, Area of matorral, Biodiversity conservation, Forest productivity, Forest management quality

5. Evaluation of data needs and availability

Data required to calculate the indicator

Total deforested surface annually(ha); total land surface (ha).

Data sources

National and European Forest Statistics (ISTAT, EUROSTAT) E.O. data

Availability of data from national and international sources

Data on forest surfaces can be provided by the Eurostat and National Statistical Organizations. Satellite data can also be used to measure current loss of forest cover.

6. Institutions that have participated in developing the indicator

Main institutions responsible

University of Basilicata

Other contributing organizations

 

7. Additional information

Bibliography

Bryan, R,B. and Campbell, I.A., 1986. Runoff and sediment discharge in a semi-arid drainage basin. Zeit fuer Geomorph., 58:121-143.

Douglas, I., 1969. Sediment yields from forested and agricultural lands, Proc. Symp. on "The Role of Water in Agriculture", University of Wales (Aberystwyth), Memorandum No. 12, E1-E22

Elwell, H. A. and Stocking M.A., 1976. Vegetal cover to estimate soil erosion hazard in Rhodesia. Geoderma, 15:61-70.

Francis, C. F. and Thornes, J.B., 1990. Runoff hydrographs from three Mediterranean vegetation cover types. In: J.B. Thornes (editor), Vegetation and Erosion, Processes and Environments. J. Wiley & Sons, Chichester, pp. 363-384.

Lee, C.R. and Skogerboe, J.G., 1985. Quantification of erosion control by vegetation on problem soils. In: Al Swaify, W. C. Moldenhauer and A. Lo (editors), Soil Erosion and Conservation. Soil Conservation Soc. of America, pp. 437-444.

Newson, M.D., 1985. Forestry and water on the uplands of Britain-the background of hydrological research and options for harmonious land use. J. Forestry, 79:113-120.

Patton, P.C. and Schumm, S. A., 1975. Gully erosion, Northwestern Colorado: a threshold phenomenon. Geology, 3:83-90.

Reed, L.A., 1971. Hydrological and sedimentation of Corey Creek and Elk Run Basins, North-Central Pennsylvania. US Geol. Surv. Water Supply Paper.

Thornes, J. B. (1988). Erosional equilibria under grazing. In J. Bintliff, D. Davidson and E. Grant (eds.) Conceptual Issues in Environmental Archaeology, Edinburgh University Press, pp. 193-210.

Williams, K.F. and Reed, L.A., 1972. Appraisal of stream sedimentation in the Susquehanna River basin. US Geol. Surv. Water Supply Paper.

Other references

 

Contacts Name and address

Prof. Agostino Ferrara
University of Basilicata
Polo Universitario di Macchia Romana
85100 Potenza, Italy
e-mail: ferrara@unibas.it