Evaluating the desertification risk assessment tool with local experimental results |
Author: Victor Jetten
Introduction
The area has shallow Cambisols (< 30 cm deep) over metamorphic shists and steep slopes. The main vegetation is pine forest, Eucalypt and shrubs, but fire destroys this and decreases the vegetation cover. The climate shows a strong seasonality despite the overall high precipitation (600-1000 mm per year) with dry summers. The landscape has steep slopes and a deeply incised drainage system.
Desertification indices
Oddly enough the desertification index scores highest for overgrazing, and fire risk, for which the area is known, scores only as low risk. The fire risk depends on land use intensity which is difficult to estimate: if tourism is counted (which is one of the causes of forest fire) and the land use intensity is increased from low to high, the fire risk increases also from 1.49 to 1.65.
Water erosion and overgrazing give the highest risk factors, respectively 3.8 and 5.4 for an intact forest with a cover of 0.5-0.75. The fire risk is low: 1.7 and there is no water stress. After a forest fire with a low cover and high percentage of forest fire these values change to 4.5 for water erosion and 4.7 for overgrazing, presumably because there is less vegetation to graze upon.
The fire risk is not affected by the burning. This may indicate a false effect: in reality a forest fire would decrease the fuel load available and greatly decrease the risk. This is in fact the purpose one of prescribed burning, which is one of the control measures tested in the project. Fire protection also hardly affects fire risk, the index decreases from 1.65 to 1.48, both in the low risk zone.
Conclusions
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Study sites
Acknowledgement
The DESIRE project was
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DESIRE brought together the expertise of
26 international research institutes
and non-governmental organisations.
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