Leaf- and ecosystem-scale photosynthetic parameters for the overstory and understory of boreal forests in interior Alaska

Masahito UEYAMA, Narumi TAHARA, Hirohiko NAGANO, Naoki MAKITA, Hiroki IWATA, Yoshinobu HARAZONO
2018 Journal of Agricultural Meteorology  
Photosynthetic parameters are key for predicting the carbon cycle and fluxes in terrestrial ecosystems. In northern high-latitude regions where cold temperatures limit available nitrogen for plants, the photosynthetic parameters are tightly linked with the nitrogen content. Here, we present the leaf-and ecosystem-scale photosynthetic parameters, the maximum carboxylation rate vcmax25 , based on leaf chamber measurements and eddy covariance data from two mature black spruce forests and one young
more » ... rests and one young aspen-birth forest in interior Alaska. The leaf carbon to nitrogen ratio C:N ratio explained most of the variations in vcmax25 across the five vascular plants Picea mariana, Betula glandulosa, Ledum groenlandicum, Betula papyrifera, and Populus tremuloides R 2 0. 68; p 0. 01 , including the overstory and understory, from the three forests. Each plant had a small within-species variability of vcmax25 and leaf C:N, suggesting that plants have a specific potential for available N in photosynthesis. This result indicates that the canopy structure and community composition are presumably important factors for modeling the canopy photosynthesis across boreal forests in interior Alaska. The ecosystem-scale vcmax25 determined from the eddy covariance data further supported this hypothesis.
doi:10.2480/agrmet.d-17-00031 fatcat:aqquvk7cxvbhdir6m3scikqtr4