What has the greatest influence on ET in rainforests?

In rainforests, precipitation plays a crucial role in influencing evapotranspiration (ET) rates. The abundant rainfall found in these ecosystems provides the necessary water supply for plants to engage in transpiration, a key component of ET. High levels of precipitation ensure that soil moisture remains consistently elevated, supporting lush vegetation and enabling a significant amount of water to be returned to the atmosphere through both transpiration from plant surfaces and evaporation from the soil.

While soil moisture, temperature, and evaporation rates are important factors that can impact ET, precipitation stands out as the primary driver in rainforests. The continuous and often heavy rainfall provides the moisture needed for plants to maintain high transpiration rates, which in turn, contributes significantly to the overall high ET observed in these ecosystems. This interconnected relationship highlights the crucial dependence of rainforest biomes on consistent, ample precipitation to sustain their ecological processes.