Harvard Forest >

Summer Research Project 2017

• Title: Forest stand dynamics measured by an above-canopy automated robotic system
• Group Project Leader: Paul Siqueira
• Mentors: Xingjian Chen; Paul Siqueira
• Collaborators: Xingjian Chen; Paul Siqueira; Mark VanScoy
• Project Description:

  Forested environments in the northeastern US undergo a tremendous amount of variability, extending from hourly diurnal changes to seasonal changes that are associated with nutrient flow that is regulated through leaf transpiration and moisture resources drawn upwards through the soil. While many of these dynamics can be studied and observed on a per-tree basis, an automated system that is capable of making the measurements over a geographically distributed region will have the advantage of observing these dynamics from time scales extending from minutes to years.
  The nutrient flow, also called sap flow, along the long distance water transport system in plants is essential in maintaining the hydraulic connection between the soil and the atmosphere. Studying the movement and dynamics of sap throughout a plant is a key to progress our scientific knowledge about plant hydraulic function or dysfunction and growth in a given environment. Transpiration in trees is difficult to measure under natural conditions because of the large size of trees and the heterogeneity of forest stands. And sap flow measurements rarely have been used to estimate transpiration for a group of trees. With the knowledge that electromagnetic field is sensitive to the dielectric constant which is determined by sap in trees, it is possible to measure transpiration of trees for a large area by microwave instruments such as radar.
  Equipped with optical and microwave instruments, an automated tram capable of making these measurements has been constructed through previous REU efforts and will be operating at the Harvard Forest. A radar system based on Ettus soft defined radio, is developed which will be integrated into the tram system this summer for short and long term dielectric constant variation measurement.
  Students working on this project will work together but with different focuses. Two research projects will be conducted.
  
  Project 1:
  The student will work on collecting tram data, maintaining and operating the system as well as augmenting its measurement system through modifications of the tram itself.
  
  Project 2:
  The student will work on correlating data from ground sap flow sensors, developing and deploying other remote control sensors for the related measurement.
  
  Interested students should have some skills in electrical engineering (basic analog circuit knowledge) and computer programming (python and Linux OS), data analysis (basic statistics), robotics and an interest in working outdoors. Must have a valid driver's license to drive Harvard Forest vehicles
  

• Readings:

  Albinet, C., P. Borderies, T. Koleck, F. Rocca, S. Tebaldini, L. Villard, T. Le Toan, A. Hamadi, A. and D. Ho Tong Minh, "TropiSCAT: A Ground Based Polarimetric Scatterometer Experiment in Tropical Forests," J. Selec. Topics. in Appl. Earth. Obs. and Rem. Sens., 5(3), 1060-1066, 2012, DOI: 10.1109/JSTARS.2012.2201917

• Research Category: Forest-Atmosphere Exchange