The Impact of Relative Humidity and Soil Moisture on Foliar Water Uptake for Urban Tree Planning
Start Date
3-16-2026 11:10 AM
End Date
3-16-2026 11:19 AM
Abstract
Foliar water uptake (FWU), uptake of water into plant leaves, occurs through several pathways during fog events. Interactions between FWU and environmental conditions must be understood to predict plant survivability in water-stressed environments, such as street tree planting, and create accurate projections of water and carbon budgets as fog regimes change. Rates of FWU are assessed assuming that water vapor can be taken up through the leaves by entering the substomatal cavity and leaf cuticle, after which it condenses and is absorbed.
Results show that FWU is highly sensitive to soil moisture and relative humidity (RH). Soil moisture at or above 0.4 m3/m3 can support transpiration and FWU rates of 0.15 µmol/sec, with FWU simultaneously occurring when relative humidity is high. Results showed that the same peak transpiration rate occurred with a high soil moisture and RH of 80% and 100%. But, the scenario with FWU (RH 100%) enabled carbon assimilation to increase by approximately 65%.
These findings have the potential to help manage stormwater and prevent runoff. When leaves continue to uptake water during drought, soil saturation may increase, increasing hydraulic conductivity, which could alter infiltration rates. Trees that efficiently uptake water are more likely to survive drought periods. The increase in tree survival would lead to their improved ability to uptake water via their roots when storm events do occur. Having a better understanding of FWU provides a more specific understanding of urban stormwater mitigation and how urban street tree planning can impact it.
Subjects
Environmental policy, GIS / modeling, Hydrology, Land use planning, Plant ecology, Sustainable development
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The Impact of Relative Humidity and Soil Moisture on Foliar Water Uptake for Urban Tree Planning
Foliar water uptake (FWU), uptake of water into plant leaves, occurs through several pathways during fog events. Interactions between FWU and environmental conditions must be understood to predict plant survivability in water-stressed environments, such as street tree planting, and create accurate projections of water and carbon budgets as fog regimes change. Rates of FWU are assessed assuming that water vapor can be taken up through the leaves by entering the substomatal cavity and leaf cuticle, after which it condenses and is absorbed.
Results show that FWU is highly sensitive to soil moisture and relative humidity (RH). Soil moisture at or above 0.4 m3/m3 can support transpiration and FWU rates of 0.15 µmol/sec, with FWU simultaneously occurring when relative humidity is high. Results showed that the same peak transpiration rate occurred with a high soil moisture and RH of 80% and 100%. But, the scenario with FWU (RH 100%) enabled carbon assimilation to increase by approximately 65%.
These findings have the potential to help manage stormwater and prevent runoff. When leaves continue to uptake water during drought, soil saturation may increase, increasing hydraulic conductivity, which could alter infiltration rates. Trees that efficiently uptake water are more likely to survive drought periods. The increase in tree survival would lead to their improved ability to uptake water via their roots when storm events do occur. Having a better understanding of FWU provides a more specific understanding of urban stormwater mitigation and how urban street tree planning can impact it.