Modeling seasonal variation of needle photosynthesis in Larix kaempferi stand

抄録

A photosynthesis model was developed to estimate the seasonal variation of needle photosynthesis (P_n) of Larix kaempferi in this study. On the basis of the physiological factors, the seasonal variation of photosynthesis was estimated from the leaf nitrogen content (N). Additionally, the effect of vapor pressure deficit (VPD) on photosynthesis was considered as the environmental factor. A positive correlation between P_n and N was found. However, there was a decrement in P_n under high VPD even though N was at the same level. Consequently, the photosynthesis-nitrogen relationships were developed by dividing VPD into two ranges: 0 < VPD < 2 and VPD ? 2. Finally, P_n was estimated from the photosynthesis-nitrogen relationships. The estimated P_n was fairly closed to the observed P_n throughout a year and represented a temporary decline which occurred frequently in summer induced by the water stress.