The effects of forest composition and management on evapotranspiration in the New Jersey Pinelands

Forests deliver contrasting ecosystem services in relation to water, both provisioning it through filtration and recharge, and consuming it through evapotranspiration. Understanding forest evapotranspiration is critical for landscapes managed in part for the social benefits of their water provisioning ecosystem services. We used the flux disaggregation algorithm for the Atmosphere-Land Exchange Inverse model (DisALEXI) with remotely sensed data to characterize landscape-scale evapotranspiration at 30-m spatial resolution over the forested coastal plain Pinelands of southern New Jersey, USA. We examined changes in evapotranspiration due to forest compositional and cover differences, then evaluated the effects of three common management actions (thinning, seed tree regeneration, and prescribed burning) on stand evapotranspiration. Among various forest compositions, upland oak forests had the lowest annual evapotranspiration, while Atlantic white cedar had the highest. In uplands, increasing proportions of conifers increased evapotranspiration, as did increased canopy cover in conifer stands. Seed tree harvests reduced evapotranspiration for about 13 years, while thinning reduced forest water use for approximately six years. Prescribed fires had variable effects, but their typical application did not reduce evapotranspiration for a complete growing season. Our research can help to inform models and decisionmaking around forests and landscape water yield.