The role of permafrost in water exchange of a black spruce forest in Interior Alaska

► Water exchange in a black spruce forest on permafrost was examined over seven years. ► Evapotranspiration (E) was supported by soil thawing and snowmelt water. ► The presence of ice-rich permafrost helps the accumulation of water in the soil. ► Cumulative E did not show noticeable interannual variability. ► Whether ice-rich permafrost exists is an important factor for determining the magnitude of the variation in E in boreal forests.