Foliar water uptake (FWU) — the direct absorption of water through leaf surfaces — is increasingly recognized as an important pathway by which trees supplement water status independent of root uptake, particularly during periods of leaf wetting from fog, dew, or precipitation. However, the extent to which surface contaminants alter this pathway remains poorly understood. In field experiments conducted in the Boston area during summer 2026, we observed measurable FWU in red maple (Acer rubrum) and red oak (Quercus rubra), alongside notable accumulation of salt deposits on leaf surfaces — a common feature of urban and coastal tree canopies exposed to road salt aerosols and sea spray. This raises the question of whether such salt deposition enhances, suppresses, or has no effect on subsequent water uptake through the leaf surface. Here, propose a pilot experiment testing the effect of a dilute saline spray (3 mg/L Na) on FWU rates in red maple and red oak, using pressure chamber (pressure bomb) measurements to quantify leaf water potential before and after treatment. This small-scale test is designed to inform the design of a larger, more comprehensive study on how surface salt interacts with foliar water absorption in urban and coastal tree species.