Over the past few decades, a change in forest composition and structure has been observed in southern Quebec (Canada), with the development of a dense understory layer of American beech (Fagus grandifolia) in stands dominated by sugar maple (Acer saccharum). The impact of this dense understory vegetation on the forest water budget remains poorly understood, although it can have important implications in terms of water availability to trees. The objective is to assess the impact of the development of a dense understory layer of American beech in sugar maple stands on rainfall interception by the canopy. Within the Kenauk private reserve, six sites were selected, including three beech-dominated sites (basal area occupied by beech saplings > 2 m2 ha-1) and three control sites (basal area occupied by beech saplings < 0.5 m2 ha-1). During the summer of 2023, we measured throughfall reaching the ground on a weekly basis using 81 containers displayed in a systematic way on the ground of each plot (total collection area = 0.87 m2). Rainfall gauges were set up in open areas near each site to measure gross rainfall and interception was computed as the difference between gross rainfall and throughfall. Results show that the presence of a dense understory layer did not influence rainfall interception by the canopy, with only rainfall intensity being a significant predictor of interception. This project will provide a better understanding of how the presence of a dense understory layer in temperate forests can affect water availability to trees.