Multiple abiotic and biotic pathways shape biomass demographic processes in temperate forests.

Area of Science:

• Ecology
• Forest Science
• Global Change Biology

Background:

• Forests are critical for the global carbon cycle, but drivers of their carbon dynamics are not fully understood.
• Abiotic and biotic factors influencing forest demographic processes need further investigation.

Purpose of the Study:

• To investigate how soil conditions and stand age affect forest biomass demographic processes.
• To determine the influence of vegetation quality and quantity on biomass dynamics.
• To quantify the contribution of growth, recruitment, and mortality to net biomass change.

Main Methods:

• Utilized repeat forest inventory data from 92,285 trees in northeast China.
• Employed structural equation modeling to analyze relationships between variables.
• Assessed the impact of soil conditions, stand age, functional trait diversity, and initial biomass stocks.

Main Results:

• Mortality was the strongest determinant of net biomass change.
• Growth, mortality, functional trait diversity, and community-weighted mean of specific leaf area (CWM_SLA) declined with stand age.
• High soil phosphorus increased functional diversity and dynamics but decreased CWM_SLA and initial biomass.
• Functional diversity correlated with recruitment, while initial biomass and CWM_SLA predicted growth and mortality, respectively.

Conclusions:

• Forest biomass dynamics are jointly constrained by multiple abiotic and biotic factors.
• Stand age and soil conditions significantly influence forest structure and function.
• Understanding these complex interactions is crucial for predicting forest responses to global change.