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Harvard Forest REU Symposium Abstract 2016

• Title: Coding Among the Trees: Automating Sap Flow Measurements
• Author: Alexandra C Widstrand (Smith College)
• Abstract:

  The water cycle in a forested environment is an important mechanism for plant respiration and the transport of nutrients through trees. Quantifying the presence of water in a forest is a complex undertaking with several possible approaches. Two such methods are being investigated and developed for use in the Prospect Hill clear-cut stand at the Harvard Forest. One approach will use a radar transceiver to send and receive signal pulses to measure trees’ water content remotely; the other will allow researchers to measure the rate of sap flow using pairs of probes inserted directly into tree trunks. Implementing these measurement systems simultaneously will enable comparison of the results and more insight into forest dynamics. While the radar will be incorporated into the robotic tram that operates over the clear-cut, the sap flow system functions separately because the probes must be physically attached to the trees of interest. The focus of this project has been to develop a standalone system that can measure diurnal sap flow in multiple trees at the same time. A single-board computer was programmed to continuously gather and store the data. The system is battery-powered and can be charged using a solar panel. The system has been tested in the field, running successfully for several days off-grid with two sets of probes. Development is ongoing for enabling remote access to the system through the Harvard Forest’s wireless network.

• Research Category: Forest-Atmosphere Exchange


• Figures:
Tree probe setup.jpg