Using branch and basal trunk sap flow measurements to estimate whole-plant water capacitance: comment on Burgess and Dawson (2008)
| Authors: | Nathan G. Phillips, Fabian G. Scholz, Sandra J. Bucci, Guillermo Goldstein, Frederick Meinzer |
| Year: | 2009 |
| Type: | Scientific Journal |
| Station: | Pacific Northwest Research Station |
| Source: | Plant Soil DOI: 10.1007/s11104-008-9741-y |
Abstract
Sap flow sensors are uniquely able to continuously monitor whole tree physiology. Recently, Burgess and Dawson (Burgess SSO, Dawson TE, Plant Soil 305:5-13, 2008) urged caution in using sap flow probes to estimate water storage use in trees. Here we respond to three criticisms raised there: (1) sampling: that tree water storage, estimated from branch-bole sap flow lags, was compromised by unaccounted variation in branch position and orientation; (2) instrumentation: that sap flow sensor response times may be sensor artifacts rather than manifestations of tree water storage; and (3) theory: that tree water storage estimates are based on a faulty concept of lag phenomena in sap flow that persists in the literature. We agree with the need for caution in sap flow-based estimates of plant water storage, but here correct flaws in arguments and representations of studies presented in Burgess and Dawson (Burgess SSO, Dawson TE, Plant Soil 305:5-13, 2008).