4.4 | Short term vs long term acclimation
In the absence of large-scale manipulative experiments with mature trees in the tropics, studies of climate change effects rely on seedling or sapling temperature and/or CO2 manipulations (e.g. Winter & Virgo 1998; Winter, Garcia, Gottsberger. & Popp 2001; Lovelock, Winter, Mersits & Popp 1998; Cheesman & Winter 2013; Slot & Winter 2017a, 2018; Fauset et al. 2019), or on manipulation of individual leaves or branches of mature trees (Körner & Würth 1996; Lovelock, Virgo, Popp & Winter 1999; Doughty 2011; Slot et al. 2014, but see Smith et al. 2020). Inferring long-term acclimation potential from manipulated pre-existing canopy leaves is challenging because newly developed tissue tends to exhibit stronger acclimation responses than pre-existing leaves. This was confirmed in our study; stronger acclimation was accomplished when plants were measured at their growth conditions than when fully-formed leaves were re-measured after the plants were switched between treatments. Acclimation of newly developed tissues is more relevant for long-term predictions and simulations.