Detecting Plant Health via Electrical Stress Response

Plants produce electrical signals which have traditionally been measured in voltage, but which have an unknown relation to plant health due to the unreliability of the voltage measurement. Using measurements of amperage, rather than voltage, we measured the electrical stress signatures produced by Douglas-fir (Pseudotsuga menziesii) trees in response to mechanical wounding. The electrical signature, which consists of a baseline signal, a spike initiated by wounding, and a subsequent signal recovery period, was measured along with controls for temperature, season, time-of-day, and soil type. We then compared the electrical stress signatures between healthy and unhealthy trees. We show that healthy trees have a characteristic electrical stress signature which is different from the electrical stress signature in unhealthy trees. Our results suggest that electrical stress signatures in amperage can be measured to reliably diagnose tree health providing a promising method for monitoring and early detection of changes in forest health.