In a recent study published in the International Forestry Review, researchers from the Food and Agriculture Organization of the United Nations (FAO) and the Forest Research Institute in Myanmar have revealed insights into the carbon density of the country's mangrove forests. The article, titled "Mangrove Biomass and Carbon Estimates for REDD+ from National Forest Inventory in Two Regions of Myanmar," confirms the assumption that mangroves are much more efficient and effective in carbon storage than most other forest types. 

Myanmar boasts the second-largest area of mangrove forests in Southeast Asia. Despite this, the region has experienced high deforestation rates and forest degradation. The study addresses the knowledge gap by providing comprehensive data on carbon content in mangrove forests, encompassing four biomass and carbon pools. Key findings include insights into:

• Carbon density surpasses previous estimates: The research indicates that the carbon density per area unit in mangrove forests is between 11–12 times higher than the values used as emission factors for the 2018 forest reference level (FRL) for REDD+ in Myanmar. This finding has important implications for understanding the role of mangrove forests in carbon sequestration.

• Resilience of heavily degraded mangroves: Even heavily degraded mangrove forests were found to store significant amounts of carbon, primarily in soil and sediments, challenging the common perception that degraded ecosystems contribute minimally to carbon storage.

• Updated emission factors: The study provides updated emission factors based on the new findings, allowing for their application in sub-national biome-wise or jurisdictional REDD+ projects or programmes. This could significantly impact future national and international carbon accounting and reporting efforts.

• Regional variations in mangrove species: The research reveals regional differences in mangrove species occurrences, with mature mangroves more frequent and extensive in the Tanintharyi region compared to the Ayeyarwady region. The information can aid in developing targeted conservation and restoration strategies.

• Biomass stock estimates for calibration: The geo-referenced biomass stock estimates at the cluster and plot levels could be crucial for calibrating biomass models in space-borne monitoring products for mangrove forests. This enhances the accuracy of satellite-based assessments of biomass, contributing to better-informed conservation efforts.

The results have immediate implications for REDD+ implementation and reporting. The updated emission factors, particularly considering the inclusion of soil organic carbon, demonstrate that mangrove areas play a more significant role in carbon sequestration than previously thought. This challenges the traditional approach of assigning lower carbon values to degraded ecosystems.

Data collection and processing

The study utilized a comprehensive data collection process through a national forest inventory (NFI) implemented during the years 2017/18 and 2019/20. The NFI was designed, tested, and operationally planned in collaboration with the UN-REDD National Programme and was initially carried out with funding from Finland in the project "National Forest Inventory, National Forest Monitoring, and Information System with a Human Rights Based Approach." 

Before field visits, a pre-assessment of candidate NFI clusters took place within ecozones based on land cover types (forest, other wooded land, other land). A satellite-based land cover assessment was carried out for all clusters on both strata, upland, and mangrove, in the land areas covered by the study. These pre-assessments were crucial for estimating land class areas and ensuring the representation of different land classes in the analysis. 

The study emphasizes the need for further research, especially in areas not covered in the current study, and stress the importance of integrating ground-based forest inventory results with satellite-based monitoring for more effective forest resource management. As Myanmar and other forested nations strive to meet climate goals, understanding the carbon wealth hidden in mangrove ecosystems becomes increasingly crucial for informed decision-making and sustainable environmental practices.

Authors:

Franz Arnold

International Expert on Forest Monitoring/REDD+ and Forest Data Management

Forestry Division, FAO

[email protected] 

MarcoPiazza

Forestry Officer

Forestry Division, FAO

[email protected] 

Maryia Kukharava

Project Officer (Programme, Advocacy and Outreach)

Forestry Division, FAO

[email protected]

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