Temperature and humidity data supporting use of an in situ passive heating method, and associated whole tree responses, Cerrado, Brazil, 2020

Internal and ambient (treatment and control respectively) air temperatures and RHs were measured by Adafruit DHT22 sensors housed inside commercial solar radiation shields (Windspeed Ltd.) and recorded to SD card by Arduino, with automatic calibration using values calculated during previous sensor testing. Sensors were placed one inside and one outside any structure being tested, and rotated between them during the testing period. Reference temperatures and RHs were measured by a local WatchDog weather station, with no extra calibration carried out. All times were converted to local time (BRT = UTC -3).
Photosynthesis and dark respiration rates were measured at incremental leaf temperatures between 20 and 50°C using two LI-6400XT portable photosynthesis systems (LI-COR Biosciences Inc.), one with a fluorometer (6400-40) chamber head and one with an LED (6400-02B) chamber head (for photosynthesis and respiration measurements respectively). Photosynthesis and respiration were measured simultaneously between 08:00 and 11:30, on two different (healthy, fully expanded, and equally mature) leaves on the same individual. Respiration leaves were covered at dawn and kept in darkness for at least 40min before testing; photosynthesis leaves were exposed to direct sunlight for at least 40min prior to testing.