Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ruehr, N.*; Bamberger, I.*; Duarte, A.*; Katata, Genki; Pointner, A.*; Arneth, A.*
no journal, ,
Heat waves strongly affect the terrestrial carbon and water cycle, with responses likely continuing past the stress event. In this study we investigated the response of carbon and water relations in Douglas-fir over three subsequent years to repeated summer heat waves under high and low water availability, intermitted by recovery periods. Tree carbon and water fluxes responded strongly to the treatments, with largest water deficits occurring under coupled heat-drought stress. Day- and nighttime transpiration increased with high temperature and evaporative demand, as long as water supply was sufficient. Assimilation in both tree species declined strongly under heat and heat-drought conditions while dark respiration increased with stress intensity in Douglas-fir. We found lagged effects on gas-exchange during the recovery periods, resulting from tight stomata regulation and impaired photosynthesis.