Milford Neck - Tree Sap Flux - Nov 2021 - ongoing

This dataset includes sap flux (cm3 cm-2 hr-1) measurements from instrumented trees at the Delaware Forested site (Milford Neck) for the CZNet Coastal Cluster. Tree sap flux reflects tree water use within xylem, rather than flow of tree sap (within phloem). Twelve Pinus taeda (loblolly pine) trees were initially selected for instrumentation. Selection was based on high canopy integrity and large DBH that was uniform across the site and reflected tree maturity. Selected trees were instrumented with heat pulse velocimetry (HPV) sap flow sensors (Implexx model, Edaphic Scientific, Melbourne, Australia). Sensors consist of three equidistant 30 mm-long probes: a central heating probe, a downstream, and an upstream probe. Each probe contains an inner and outer thermistor for functional redundancy and cross-sectional averaging. The Implexx HPV sensors work functionally similar to thermal dissipation probes. Sensors were installed in tree trunks at 1 m in height above the soil surface on the south side of the tree trunk. Bark thickness was shaved to <0.5 cm thickness in a small area for the probe installation so that thermistors were installed in sapwood. Data from sensors was collected every 30 minutes with a CR300 datalogger (Campbell Scientific). Power was supplied with a 7W solar panel and stored in a 12V sealed lead-acid battery. Because the datalogger batteries occasionally died or failed to charge by the solar power (particularly in mid-summer, when the forest canopy was full), there may be gaps in the record.