Populus nigra L. × P. maximowiczii Henry) and black locust ( Robinia pseudoacacia L.) in a temperate agroforestry system]]>

摘要

A leaf net photosynthesis model is presented driven by light and modulated by temperature and air humidity. From this the seasonal variation of CO~(2)uptake and release could be modelled to estimate the annual carbon fluxes of sun and shade leaves. In fully expanded leaves light is the major factor determining daily carbon balances, and highest observed daily carbon gains in sun leaves amounted to 748.9?mmol CO~(2)m_(?2)day_(?1)in poplar and to 536.3?mmol CO~(2)m_(?2)day_(?1)in black locust, while the annual carbon gains amounted to 46,824?mol CO~(2)m_(?2)in black locust and 66,803?mol CO~(2)m_(?2)in hybrid poplar. Results obtained via gas exchange measurements and from the leaf model clearly indicate a potentially better growth performance of the poplar compared to black locust on the investigated site. The presented photosynthesis model provides a good and realistic estimation for seasonal carbon balances on the leaf level for both species.