Hill Demonstration Forest HF1 and HF2 riparian buffer and HF2 upland sap flow data

This data publication contains hourly sap flux data from three locations (defined as HF1 riparian buffer, HF2 riparian buffer, and HF2 upland) in a pair of watersheds on the Hill Demonstration Forest (HF). Sap flux density was monitored at the HF1 riparian buffer location in the following species from 2010-2016: loblolly pine (Pinus taeda), sweetgum (Liquidambar styraciflua), red maple (Acer rubrum), white oak (Quercus alba), and tulip poplar (Liriodendron tulipifera). At the HF2 riparian buffer location sap flux density was monitored from 2010-2016 in the following species: loblolly pine, sweetgum, red maple, tulip poplar, American beech (Fagus grandifolia), white oak, and Virginia pine (Pinus Virginia). Thirdly, sap flux density was monitored at the HF2 upland location from 2015-2016 for the following species: loblolly pine, sweetgum, red maple, tulip poplar, chestnut oak (Quercus montana), and Virginia pine. The HF is located north of Durham, North Carolina and is owned by North Carolina State University. Upland trees were harvested in HF1 watershed from 29 November 2010 to 19 January 2011 as part of a Timber Harvest/Best Management Practices Project, leaving a 15.2-meter (m) riparian buffer on either side of the stream. HF1 is the treatment watershed, and HF2 is the reference watershed. Therefore, no logging activities occurred in HF2. Although HF1 and HF2 are paired and share a watershed boundary line, the clearcut edge in HF1 is 130 m from HF2 monitored riparian buffer trees and poses little chance to create changes in HF2 riparian buffer soil or canopy conditions that would influence their water use. The riparian buffer covers about 8% of the watershed area in both HF1 and HF2.
Quantifying species sap flux density (i.e., tree water use) is essential to improve stand-scaled transpiration estimates, and to refine the forests role in the hydrological cycle. In addition, linking soil moisture, tree water use, and climate conditions at the watershed level is rarely done, but is critical to refining water loss estimates from forest, managing the effects of drought, and understanding hydrological processes in unmanaged and managed watersheds across various regions. New plantations are being planned across the southern United States to meet the rising demand for wood production. This type of data could help public and private landowners decide which trees might be better to maximize the benefits and costs related to water in tree planting across the Piedmont. This data publication is used by USDA Forest Service scientists, staff and cooperators in support of research in hydrology, watershed management, silviculture, and forest ecology in the North Carolina Piedmont Region.