Joint Influence Mechanism of Phenology and Climate on the Dynamics of Gross Primary Productivity: Insights From Temperate Deciduous Broadleaf Forests in North America

Abstract

AbstractUnderstanding the influence mechanism of biotic and abiotic factors on the dynamics of gross primary productivity (GPP) is crucial to accurately simulate the terrestrial carbon cycle. Based on the carbon flux data, meteorological data (i.e., temperature, precipitation, vapor pressure deficit, and radiation) and phenological metrics (i.e., the date of greenup, maturity, senescence, and dormancy) collected from six North America temperate deciduous broadleaf forests (NAT‐DBF) sites, this study investigated the joint influence mechanism of phenology and climate on the dynamics of GPP by using commonality analysis and structural equation modeling. The results showed that precipitation, the date of maturity and senescence jointly dominated the dynamics of annual GPP in NAT‐DBF. The date of maturity and senescence rather than the date of greenup and dormancy were crucial phenological metrics that directly influenced the dynamics of annual GPP. There existed an important indirect influence path of temperature on the dynamics of annual GPP through regulating the date of maturity, while the direct influence of temperature on the dynamics of annual GPP was negligible. Precipitation not only directly influenced the dynamics of annual GPP, but also indirectly influenced the dynamics of annual GPP through regulating the date of senescence. Our study provides a process‐based understanding for the joint influence mechanism of meteorological factors and phenology on the dynamics of annual GPP, which is helpful for understanding the vegetation responses to climate change and improving the process‐based ecosystem models.