Thresholds Database > Climate change with rooting depth, Amazon, South America

Background

This study links vegetation type, rooting depth and climate in the Amazon Basin.

Alternate Regimes

1. Forested areas with a consequent wetter, shorter, dry season

2. Deforested areas with a consequent warmer, longer, dry season

Mechanism

During the dry season, water transpired by plants contributes substantially to atmospheric moisture, increasing relative humidity. Vegetation type determines rooting depth, which in turn partly determines the availability of soil moisture for evapotranspiration. The climate in the deforested landscape, where shallower rooted plants prevail, has more frequent long dry periods, which are warmer, drier and more intense than in forested areas.

Management Decisions in Each Regime

State 1: Most of the modelled climatic changes arising from large-scale deforestation can be attributed to the removal of deep roots. The longer, dryer periods could make it more difficult for deep-rooted evergreen forest to become re-establishment.