Code
F04
Sector
Forest
The complete description of the NWRM
Summary

There is some evidence to suggest that loss of tree cover on Mediterranean hill slopes has altered weather patterns, which in turn have altered precipitation amount and timing. Modelling results suggest that Mediterranean precipitation regimes are very sensitive to variations in air temperature and moisture. Land use change and associated deforestation may have led to changes from and open monsoon-type regime with frequent summer storms over inland mountains to a regime dominated by closed vertical atmospheric recirculation where feedback mechanisms suppress storms over the coastal mountains and lead to increased summer time sea surface warming. This warming leads to torrential rains in autumn and winter. These rains can occur across the Mediterranean basin. This can be exacerbated by greenhouse heating associated with air pollutants.  Targeted afforestation in some parts of the Mediterranean may be one means of combating drought and desertification. However, caution should be taken when choosing areas for afforestation to avoid possible adverse effects, as there is some evidence that afforestation in dry environments, especially in montane areas, may decrease water yield and cause water deficit in the downstream rivers. Local tree species should be used to reduce risks to biodiversity.

Illustration(s)

Functioning of the water cycle in forests

Source: http://www.nature.com/nature/journal/v489/n7415/full/nature11485.html?WT.ec_id=NATURE-20120913(link is external)

 

Possible benefits with level

Case studies per NWRM

Reforestation in Veneto, ItalyWater retention spaces, reforestation and grazing management  in southern Portugal
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