Use of a thermocouple-datalogger system to evaluate overstory mortalityThis article is part of a larger document. View the larger document here.
In the past, it was difficult to accurately measure dynamic fire behavior during prescribed burns. Peak temperature, flaming duration, and total heat output may be directly related to first-order fire effects such as fuel consumption and vegetative mortality; however, little is known about which of these variables is most closely associated with, and therefore the best predictor of, post-burn conditions. A thermocouple-datalogger system can allow forest managers and scientists to record data related to maximum temperature, heat pulse duration, and total heat output at any location within a prescribed burning treatment area over a user-defined time period. The advantage of this type of system is its ability to evaluate the rate of spread and intensity of a prescribed burn, and to relate those spatial variabilities to short- and long-term effects such as tree mortality. Regression equations of fire attributes and overstory mortality indicated that immediately following the first fire, flaming duration and average flame temperature together explained 43 percent of the mortality observed. After two years, average temperature alone showed the strongest relationship to mortality but only accounted for 24 percent of the variance. Overstory mortality was lower after the second burn, with total heat output explaining 45 percent of model variation.