The Center for Standardization of Disaster Resilience and Climate Change Instruments, Indonesia Ministry of Environment and Forestry, and the Mushroom Initiative collaborated from early 2020 to September 2023 to reforest degraded Indonesian peatlands using the 4N rehabilitation concept. The 4N approach stands for: No plastic (replacing plastic polythene bags with biodegradable pots made from purun grass and bamboo during planting), No burning (employing local community land preparation instead of burning), No chemical fertilizer (using mycorrhizal fungi instead of chemical fertilizers), and promoting Native peatland tree species over non-peatland trees. Through the 4N concept we can simultaneously restore peatland ecosystems and reduce and avoid greenhouse gas emissions to help mitigate climate change. Fire is a major threat to peatlands, and intensive maintenance is one of the main components of successful peatland reforestation.

The project involved eight researchers with expertise in microbiology, silviculture, genetics, carbon valuation, forest community empowerment and policy, and more than 10 stakeholders. We collaborated to rehabilitate c. 116 ha of tropical peatlands in Pedamaran, South Sumatra (51 ha) and Tumbang Nusa, Central Kalimantan (65 ha). More than 190,000 seedlings of 50 native peatland species were planted and inoculated with 15 mycorrhiza species. Planting took place each year, starting in 2020 and concluding in March 2023. A final evaluation in early September 2023 showed that seedling survival exceeded 70%.

The 4N approach has several benefits. Replacing plastic polythene bags, which have a carbon footprint of 6 kg CO2 per 1 kg of plastics (timeforchange.org/plastic-bags-and-plastic-bottles-co2-emissions-during-their-lifetime), eliminates 54 kg CO2/ha of emissions. Avoiding fire use through manual land preparation can potentially prevent a total of 290 t CO2/ha of emissions from burned peat soils (Agus, 2008, International Symposium on Land Use after the Tsunami, 5, 103–109) and shrubs (Volkova et al., 2021, Fire, 4, 64). The use of mycorrhizal fungi is estimated to avoid the use of up to 187 kg/ha of fertilizer, thereby reducing emissions from chemical fertilizers by 82 kg CO2/ha (2006 IPCC Guidelines for National Greenhouse Gas Inventories, 2006, Institute for Global Environmental Strategies, Japan). In addition to their adaptability to local sites, selecting native tree species also reduces the carbon footprint associated with transporting seedlings. Planting native species in waterlogged tropical peatlands reduces carbon emissions from peat oxidation but can necessitate up to three plantings because of the challenging conditions. The 4N approach is a departure from outdated revegetation practices, offering sustainability, community involvement, and a reduced carbon footprint, thus contributing to a sustainable future.

The making of purun pots for raising seedlings as an alternative to polythene bags, and 3-year old planting of the native peatland species Shorea balangeran. Photos: Wahyu Catur Adinugroho.