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

Authors: ISAACSON, B. - Rutgers University; YANG, YUN - US Department Of Agriculture (USDA); CLARK, K - Us Forest Service (FS); Anderson, Martha; GRABOSKY, J. - Rutgers University

Submitted to: Agricultural and Forest Meteorology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/28/2023
Publication Date: 7/8/2023
Citation: Isaacson, B., Yang, Y., Clark, K., Anderson, M.C., Grabosky, J. 2023. The effects of forest composition and management on evapotranspiration in the New Jersey Pinelands. Agricultural and Forest Meteorology. 339. Article e109588. https://doi.org/10.1016/j.agrformet.2023.109588.
DOI: https://doi.org/10.1016/j.agrformet.2023.109588

Interpretive Summary: Forest management actions, such as thinning, harvest, and fire suppression, can have significant and sometimes unanticipated effects on the water balance within the forest and the water yield from forested lands. Models and policies that attempt to account or manage forests for ecosystem services should be sensitive to the hydrologic behavior of different forest disturbance events. To this end, satellite remote sensing can provide fine-grained, spatially continuous geospatial information on evapotranspiration (ET), or consumptive water use, that is not possible with other methods. This paper investigates utility of 30-m daily ET maps generated from Landsat imagery to provide hydrologic decision support for forest and water management in the New Jersey Pinelands, the largest forested landscape on the mid-Atlantic coastal plain. Specifically, we quantify water use response by tree species to harvest, thinning, and prescribed fires. There was a variable effect of management on water yield, where the intensity and duration of the ET anomaly was qualitatively related to the intensity of overstory disturbance. This research can help to inform data-driven decision-making in managing this or other forests for water yield.

Technical Abstract: Forests have contrasting roles in ecosystem services with relation to water, both provisioning it through filtration and recharge, and consuming it through evapotranspiration. Understanding forest evapotranspiration is critical for landscapes purchased and managed for the social benefits of their water provisioning ecosystem services. We used the flux disaggregation algorithm for the Atmosphere-Land Exchange Inverse model (DisALEXI) to characterize landscape-scale evapotranspiration 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. 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. Seed tree harvests reduced evapotranspiration for about 13 years, while thinning reduced forest water use for roughly 5 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 decision-making about managing this or other forests for water yield.