StorAge Selection (SAS) function application to whole tree water storage and transport using enriched 2H tracing and sap flow in two tree species of North Carolina
Abstract
Tree water use and storage are dynamic in space and time. Understanding how trees store and use water is critical to modeling water balances and hydrological fluxes in forested ecosystems. Further, tree species vary in their ecohydrological properties and strategies for water storage and transport. Our objective was to quantify spatial and temporal variability in residence time and location of water for two tree species with different wood anatomy and hydraulic strategies. We selected one gymnosperm (loblolly pine; Pinus taeda L.) and one angiosperm (southern red oak; Quercus falcata) tree species, both of which are common in the Piedmont region of North Carolina, USA. In July 2021, 99.9 % atom enriched deuterated water (D2O) was injected as a tracer to the base of four trees in each species. For the next 45 days we tracked movement of the tracer axially and radially in tree stems by analyzing water vapor from a series of boreholes at three heights on the stem. At each height, three boreholes were installed to observe tracer presence radially at three locations: 1) shallow sapwood; 2) deep sapwood; and 3) heartwood. Isotopic data was used to parameterize a model of StorAge Selection (SAS) functions, utilizing the concentration of tracer input (e.g., injected 2H) and output concentration (e.g., 2H breakthrough curves). The SAS function analysis allows for inference of mixing and transport processes within a hydrological system by relating the age distribution of stored water to that of the water flux leaving the storage. Typically, SAS functions have been utilized to model hydrological fluxes at the catchment scale, but the potential of this approach for water transport within trees has rarely been explored.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.B55G1055M