Comparison of sapling-level daily light capture and carbon gain between a temperate deciduous and a co-occurring evergreen tree species in the growing season and in winter

Abstract

Light capture efficiency (Ea) and mass-based daily carbon gain (Amass) were compared between saplings of a deciduous tree species, Ficus erecta Thunb. and the co-occurring evergreen broadleaved tree species, Neolitsea aciculata (Bl.) Koidzumi, in a temperate forest in Japan. Using obtained data and an ecophysiological–architectural model, we calculated the Ea and Amass of each study sapling. We also analysed the response of Amass to changes in photosynthetic traits and Ea. Saplings of F. erecta had a higher Amass than N. aciculata, due to the high leaf area : aboveground mass ratio (LAR). The model calculation suggested that changes in photosynthetic traits and Ea changed Amass but did not modify the interspecific difference of Amass. In winter Amass was lower than that in the growing season due to low light availability during the short day lenght, suggesting modest importance of winter carbon gain for the evergreen saplings of N. aciculata. In conclusion, the advantage of this deciduous species for carbon gain over the co-occurring evergreen broadleaved saplings is not modified by acclimative changes in leaf physiology, crown architecture or prolonged photosynthesis period by evergreen broadleaved trees.