Fog mitigates the consequences of a profligate water use strategy in a Macaronesian cloud forest tree species

•Fog led to a 45% reduction in global radiation and an associated sap flow decrease.•Canopy remained wet during at least 55% of the time due to fog water interception.•Trade wind inversion altitude changes affect night-time sap flow and canopy wetting.•Night time sap flow represented 23% of the daily transpiration in M. faya.•Foliar water uptake in M. faya occurred with a 27% frequency.