Thinning practices in rehabilitated mangroves: Opportunity to synergize climate change mitigation and adaptation

Mangrove trees act important roles in the coastal ecosystems, protecting community against high-tide and\ud storms, controlling land erosion and providing fish breeding ground. In the last few decades, the massive area has\ud devastated due to commercial shrimp and fish ponds development. To rehabilitate the coastal ecosystems, some\ud mangrove has been planted with spacing distances of 1x1 m with minimal forest management. Those dense-spaced\ud stands enhanced light competitions and inhibit growth. These poor quality and immature stands that reach an early\ud climax in 10-15 years were observed in two adjacent sites near Nam Dinh and Thanh Hoa in northern Vietnam, where\ud Kandelia candel were planted. To cultivate the resurgent stands and increase their growth, thinning mangrove is\ud essential. Stand densities of the mangrove trees with and without the thinning practice were 17,800 and 5,200 trees ha-1,\ud respectively. Their potential of the maximum above-ground biomass were 303 and 239 Mg ha-1, respectively. However,\ud quality of the single tree was largely different whether or not thinning practice is conducted, as the thinned one of 46 kg\ud tree-1 was about three times higher than the non-thinned of 17 kg tree-1. The thinning practice enhances stand biomass\ud growth with improved growth condition in the forest, which advances carbon sequestration for the climate change\ud mitigation. The cultivated trees also ensure the climate change adaptation of coastal protection, fishery products and\ud bio-diversity. Synergizing mitigation and adaptation strategies with the mangrove thinning would enhance the benefits\ud for coastal communities most vulnerable to climate change

Challenges and opportunities for achieving Sustainable Development Goals through restoration of Indonesia’s mangroves

Indonesia, the most mangrove-rich nation in the world, has proposed the most globally ambitious mangrove rehabilitation target (600,000 ha) of any nation, to be achieved by 2024 to support multiple Sustainable Development Goals (SDG 1–3, 6, 13 and 14). Yet, mangrove restoration and rehabilitation across the world have often suffered low success rates and been applied at small scales. Here, we identify 193,367 ha (estimated costs at US$0.29–1.74 billion) that have the potential to align with the national mangrove rehabilitation programme. Despite being only 30% of the national target, our robust assessment considered biogeomorphology, 20 years of land-use and land-cover change and state forest land status, all key factors moderating mangrove restoration success which have often been neglected in Indonesia. Increasing subnational government representation in mangrove governance as well as improving monitoring and evaluation will increase the likelihood of achieving the mangrove rehabilitation targets and reduce risks of failure. Rehabilitating and conserving mangroves in Indonesia could benefit 74 million coastal people and can potentially contribute to the national land-sector emissions reduction of up to 16%