UNDERSTANDING mass and energy exchange between vegetation and the atmosphere is essential for determining the future state of the climate system(1,2) and responses of plant communities. Plant water use is at present described by steady-state transport models(3,4), even though transport in the boundary layer is turbulent(5,6). This is especially true for forests, where the canopy air space is a chaotic environment where large turbulent events alternate with smaller-scale mixing(3,4,7). Here we demonstrate that the turbulent nature of the atmosphere affects plant processes. We propose that the dynamic nature of plant-atmosphere coupling represents a previously unrecognized feedback that influences plant water use and transport.