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How does forest clearing change the water cycle?
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Deforestation
A section of clear-cut forest in Romania.
Forest clearing significantly alters the hydrologic cycle by disrupting the mechanisms that regulate water interception, storage, and flow.1
When forests are removed, several critical changes occur:
- Reduced Evapotranspiration: Forests facilitate the movement of water from the soil into the atmosphere through transpiration and evaporation. Clearing trees reduces this process, which can decrease local rainfall, particularly in regions like the Amazon Rainforest where recycled moisture accounts for a significant portion of precipitation.123
- Increased Runoff and Flooding: Forests act as sponges that filter and store water. Unforested land sheds water swiftly, leading to rapid, high-volume streamflow and increasing the risk of floods.1
- Water Table Changes: In wet areas, the removal of the forest canopy often raises the water table, which can limit the ability of remaining vegetation to thrive.1
- Degraded Water Quality: Without the filtering action of forest soils and litter layers, water quality often declines. Deforestation can lead to increased turbidity (suspended solids), higher water temperatures, and increased nutrient content in streams.1
These changes demonstrate that forests are essential for maintaining reliable, uniform water yields and protecting the stability of regional climates.14