[rolph]

leaf temperature is the issue. photosynthetic machinery begins to denature at 30C leaf temperature, this is physiologic break even point. plants become stunted and just survive, rather than produce net gain of biomass

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC129275/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10422931/