Understory Evapotranspiration Rates in a Coast Redwood Forest

In forests where the overstorey canopy has been disturbed by timber harvest or other means, evapotranspiration (ET) understorey may be main flux of water back to atmosphere. However, little research apportioned directly measuring use, and technology do so is thus limited. Here, we used a portable chamber quickly measure ET from soil vegetation enclosed chamber. This method was in third-growth coast redwood forest rates individuals five species commonly found understorey: Sequoia sempervirens (coast redwood) sprouts, Notholithocarpus densiflorus (tanoak) Vaccinium ovatum (evergreen huckleberry) Polystichum munitum (sword fern) Struthiopteris spicant (deer fern). Measurements were conducted four small watersheds which harvested varying intensities ranging 0% 75% targeted reduction preharvest overstory basal area. Mean rate highest watershed with lowest residual area (x̅ = 0.036 ± 0.024 mm/h) unharvested control 0.013 0.0078 mm/h). Multiple regression modelling on resprouting indicated that difference between related light resources. These results imply use can significant, particularly watersheds, should quantified at landscape scale.