Mangroves are an important ecosystem that provides valuable social, economic, and environmental services. Indonesia has placed mangroves on its national priority agenda in an important effort to sustainably manage this ecosystem and achieve national climate commitments. However, mangrove management is faced with complex challenges encompassing social, ecological, and economic issues. In order to achieve the government’s commitments and targets regarding mangrove restoration and conservation, an in-depth study on and critical review of mangrove management in Indonesia was conducted herein. This work aimed to provide a comprehensive analysis of the challenges and strategic recommendations for sustainable mangrove management in Indonesia. SWOT analysis was carried out to understand the strengths, weaknesses, opportunities, and threats related to mangrove management in Indonesia. To address these gaps, we reviewed the existing policies, current rehabilitation practices, environmental challenges, and research and technology implementations in the field. We found that strategies on mangrove ecosystem protection, such as improving the function and value of mangrove forests, integrating mangrove ecosystem management, strengthening political commitments and law enforcement, involving all stakeholders (especially coastal communities), and advancing research and innovations, are crucial for sustainable mangrove management and to support the national blue carbon agenda.

Pinus merkusii Jungh et de Vriese, known as Tusam or Sumatran pine, is the only pine that grows naturally in the south of the Equator with its natural distribution found in Indonesia, the Philippines, Myanmar, Thailand, Laos, Cambodia, and Vietnam. The Sumatran pine is an economically and ecologically important species in Indonesia that covers three native strains, Aceh, Kerinci, and Tapanuli. The resin tapping of the pine has been practiced for hundreds of years while its timber has long been commercially used for various purposes. Although the pine is known as highland species, its adaptability on a wide spectrum environment makes it suitable for various restoration and rehabilitation purposes both in lowland and highland sites. Its high commercial values have also made the species be massively planted in pine plantations outside their natural distribution in Sumatera (i.e., in Java and Sulawesi island). This paper will review the current condition of Sumatran pine and its potential as a restoration and rehabilitation species and delivering its natural and artificial distribution map in Indonesia. In addition, the paper will also show the genetic variability of the species, determine the current innovative practices in silvicultural aspect both at nursery and plantation scales, describe tree improvement program, including its role in agroforestry practices, pine product both timber and non-timber, and its potential resources in relation with climate change mitigation management.

Tropical peatlands are areas of high carbon density that are important in biosphere-atmosphere interactions. Drainage and burning of tropical peatlands releases about 5% of global greenhouse gas (GHG) emissions, yet there is great uncertainty in these estimates. Our comprehensive literature review of parameters required to calculate GHG emissions from burnt peat forests, following the international guidelines, revealed many gaps in knowledge of carbon pools and few recent supporting studies. To improve future estimates of the total ecosystem carbon balance and peatfire emissions this study aimed to account for all carbon pools: aboveground, deadwood, pyrogenic carbon (PyC) and peat of single and repeatedly burnt peat forests. A further aim was to identify the minimum sampling intensity required to detect with 80% power significant differences in these carbon pools among long unburnt, recently burnt and repeatedly burnt peat swamp forests. About 90 Mg C ha^-1 remains aboveground as deadwood after a single fire and half of this remains after a second fire. One fire produces 4.5 ± 0.6 Mg C ha^-1 of PyC, with a second fire increasing this to 7.1 ± 0.8 Mg C ha^-1. For peat swamp forests these aboveground carbon pools are rarely accounted in estimates of emissions following multiple fires, while PyC has not been included in the total peat carbon mass balance. Peat bulk density and peat carbon content change with fire frequency, yet these parameters often remain constant in the published emission estimates following a single and multiple fires. Our power analysis indicated that as few as 12 plots are required to detect meaningful differences between fire treatments for the major carbon pools. Further field studies directed at improving the parameters for calculating carbon balance of disturbed peat forest ecosystems are required to better constrain peatfire GHG emission estimates.

Gunung Dahu Research Forest (GDRF) is a 250 ha tropical degraded land reforested by native dipterocarps species. The reforestation success was valued by evaluating the planted trees’ growth performance, their potential timber stock, natural regeneration capacity, soil improvement, biological interdependence, and environmental services. This scientific report used a combination of literature review and also primary data processing to describe the reforestation success within the area. A hilly species of Shorea platyclados showed the best growth performance with its average diameter and height of 43 cm and 23 m, respectively, with its mean diameter annual increment of 2.1 cm/year and the predicted standing stock at 220 m³/ha. Six Shorea species were identified to show their natural regeneration capacity and the occurrence of ectomycorrhizal fruiting bodies, predominantly by the genus Rusula, determined the establishment of biological interdependency at the site. Reforestation improved soil organic matters as revealed by high soil porosity (51.06–52.32%) and infiltration rate (120–155.33 mm/h). The reforested landscape also ensures a continuous water supply and provides an economic benefit for the community. Thus, planting native trees for reforesting degraded tropical landscapes is prospective and may deliver multiple benefits in an ecological and economic view.

Although accurate estimates of biomass loss during peat fires, and recovery over time, are critical in understanding net peat ecosystem carbon balance, empirical data to inform carbon models are scarce. During the 2019 dry season, fires burned through 133,631 ha of degraded peatlands of Central Kalimantan. This study reports carbon loss from surface fuels and the top peat layer of 18.5 Mg C ha⁻¹ (3.5 from surface fuels and 15.0 from root/peat layer), releasing an average of 2.5 Gg (range 1.8–3.1 Gg) carbon in these fires. Peat surface change measurements over one month, as the fires continued to smolder, indicated that about 20 cm of the surface was lost to combustion of peat and fern rhizomes, roots and recently incorporated organic residues that we sampled as the top peat layer. Time series analysis of live green vegetation (NDVI trend), combined with field observations of vegetation recovery two years after the fires, indicated that vegetation recovery equivalent to fire-released carbon is likely to occur around 3 years after fires.