Sunlight and wind provide the energy to drive the process of water evaporation.
Following rainfall, water is intercepted by the forest canopy and directly evaporated back to the atmosphere.
Leaves, understorey and ground vegetation
Tree species vary in their ability to control water loss via stomata; water is lost through these open pores on the leaf surface during transpiration.
Water is also lost by evapotranspiration from any understorey or ground vegetation, although at a lower rate due to the shaded and sheltered conditions.
Soil and roots
Soil drying during summer reduces the amount of 'available; water and can lead to trees closing their stomata, thus reducing the transpiration loss.
Root uptake of water from the soil supports the 'transpiration stream'.