Planting large amounts of trees may add a lot to improving an ecosystem, and in mitigating atmospheric CO2-levels. But planting trees in arid areas can sometimes worsen the environmental circumstances, especially the water availability for people living downstream. Environmental researchers from Utrecht University studied over 400.000 watersheds worldwide. Their results have been published in Nature.
Deforestation and afforestation have been studied many times worldwide, mostly in terms of climate impact. The effects of forest management on streamflow however is less well-known. For over 100 years researchers have been studying the prediction of streamflow response to forest planting and removal. But until now the results were exceptionally unclear and largely unpredictable.