Mixed Forestation Outperforms Pure Stands in Soil Carbon Sequestration and Stability

Area of Science:

• Forest ecology
• Soil science
• Climate change mitigation

Background:

• Forestation is key for soil organic carbon (SOC) sequestration.
• Global data on pure vs. mixed forest impacts on SOC fractions and stability is limited.

Purpose of the Study:

• To quantify the global effects of pure and mixed forestation on SOC fractions and stability.
• To identify factors regulating SOC responses to forestation.

Main Methods:

• Meta-analysis of 4052 observations from 102 sites.
• Comparison of SOC, POC, and MAOC changes under pure and mixed forestation.
• Analysis of SOC stability indicators (MAOC:POC ratio).

Main Results:

• Mixed forestation significantly increased SOC (64.3%), POC (86.9%), and MAOC (65.3%).
• Pure forestation increased SOC and POC but not MAOC, and reduced SOC stability (MAOC:POC ratio by 24.9%).
• Prior land use and plantation age modulated SOC sequestration and stability.

Conclusions:

• Mixed forestation enhances both SOC storage and stability, offering a resilient carbon sequestration strategy.
• Mixed-species plantations should be prioritized for climate mitigation and ecosystem restoration policies.