| dc.description.abstract | Mangrove forests are an integral component of blue carbon ecosystems and play an important role in climate change mitigation. Atmospheric carbon dioxide (CO2) is absorbed through photosynthesis and converted into carbohydrates, which are subsequently stored as biomass in leaves, stems, and roots. Carbon is also stored in sediments through the decomposition of dead plant materials and the deposition of organic matter transported by tidal processes, which is subsequently buried and preserved under anaerobic conditions.
Mangrove ecosystems face increasing challenges associated with changes in forest extent resulting from global climate change and anthropogenic disturbances. Mangrove restoration is therefore considered a nature-based solution that contributes to ecosystem recovery and the achievement of the Sustainable Development Goals (SDGs). This study was conducted in two regions: East Java, covering Mangrove forests in Mangunharjo Urban Village and Dringu Village, and North Sumatra, covering Lubuk Kertang Village and Tanjung Rejo Village.
The study had four objectives: (1) to analyze mangrove species composition and measure the physicochemical characteristics of soil and water; (2) to quantify carbon stocks and carbon sequestration rates; (3) to map actor influence, dependence, and mobilization toward restoration objectives; and (4) to estimate the economic value of carbon based on voluntary carbon market prices. Carbon stocks were quantified non-destructively in restored mangrove forests aged 8, 14, and 20 years. The 8-year-old stands were selected because the trees had developed secondary xylem, the 14-year-old stands represented an intermediate stage, and the 20-year-old stands represented the climax stage. Biomass was estimated using general allometric equations based on two parameters: tree diameter (D) and diameter-height (DT), under two conditions: (1) ideal intact conditions (Di; DTi), in which all trees within the subplots were assumed to be alive; and (2) actual conditions (Da; DTa), in which all trees were recorded according to their actual field conditions, including both living and dead trees.
The mangrove species composition in East Java was dominated by Rhizophora mucronata (Importance Value Index [IVI] 183.14%), followed by R. stylosa (49.57%). In North Sumatra, the mangrove community was dominated by R. apiculata (IVI 192.03%), followed by R. mucronata (61.58%). The physicochemical characteristics of the mangrove environment did not differ significantly, with soil pH ranging from 3.8–6.0; soil moisture from 5.4–7.7; soil temperature from 25.3–31.0 °C; conductivity from 3.5–4.0 mS cm?¹; water temperature from 26.3–32.6 °C; water TDS from 25.4–38.8; EC from 37.8–59.60 mS cm?¹; ORP from 86.0–167.4; salinity from 24.9–41.8 ppt; and soil bulk density from 0.81–1.03 g cm?³.
In East Java, the mean carbon stock at 8, 14, and 20 years of age estimated using the ideal diameter-based allometric equation (Di) was 42.33 ± 4.36, 70.97 ± 11.87, and 96.11 ± 17.70 Mg C ha?¹, respectively, whereas the actual condition (Da) yielded 41.79 ± 4.11, 69.08 ± 11.68, and 93.08 ± 17.03 Mg C ha?¹, respectively. Using the ideal diameter-height allometric equation (DTi), the corresponding values were 43.47 ± 5.74, 88.67 ± 12.92, and 116.13 ± 22.66 Mg C ha?¹, while the actual condition (DTa) produced 43.06 ± 5.59, 86.61 ± 12.85, and 113.93 ± 22.05 Mg C ha?¹, respectively. In North Sumatra, the mean carbon stock at 8, 14, and 20 years based on the Di equation was 42.33 ± 4.36, 70.97 ± 11.87, and 96.11 ± 17.70 Mg C ha?¹, respectively, whereas the Da estimates were 41.79 ± 4.11, 69.08 ± 11.68, and 93.08 ± 17.03 Mg C ha?¹. Based on DTi, the corresponding values were 43.47 ± 5.74, 88.67 ± 12.92, and 116.13 ± 22.66 Mg C ha?¹, while DTa produced 43.06 ± 5.59, 86.61 ± 12.85, and 113.93 ± 22.05 Mg C ha?¹, respectively.
Total ecosystem carbon (TEC) in East Java ranged from 250.92 ± 1.23 to 390.02 ± 7.28 Mg C ha?¹, whereas in North Sumatra it ranged from 289.66 ± 3.86 to 416.08 ± 24.05 Mg C ha?¹. The annual carbon sequestration rate in East Java ranged from 18.40–19.82 Mg CO2e ha?¹ year?¹, while that in North Sumatra ranged from 49.97–56.02 Mg CO2e ha?¹ year?¹.
The influence and dependence analysis indicated that mangrove restoration governance in East Java and North Sumatra exhibited similar patterns, characterized by government institutions acting as key decision-making actors, supported by facilitating institutions serving as bridging actors. Meanwhile, academic institutions, village and subdistrict governments, and local community groups remained relatively less active. Actor mobilization indicated that mangrove restoration in both East Java and North Sumatra received positive support without explicit opposition. However, the mobilization priorities remained unbalanced between ecological, economic, and social interests.
The estimated economic value of carbon (EVC), based on the average global voluntary carbon market price of USD 30 tCO2e?¹ and an exchange rate of USD 1 (IDR 17,000), ranged from IDR 408,065,338 to IDR 551,618,532 for restored mangrove forests in East Java, covering an area of 136.45 ha. In North Sumatra, covering 2,221.18 ha, the estimated EVC ranged from IDR 20,650,587,526 to IDR 26,816,990,839. The estimated allocation per hectare was IDR 7,300,404 ha?¹ in East Java and IDR 22,552,772 ha?¹ in North Sumatra. Under the National Economic Value of Carbon (NEK) framework established by Presidential Regulation No. 110 of 2025 and Minister of Forestry Regulation No. 6 of 2026, the economic benefits generated from carbon projects should be managed through a fair, accountable, and transparent benefit-sharing mechanism. The distribution of carbon-related economic benefits should not be limited to investors or project developers but should also provide equitable benefits to local communities, government institutions, and other relevant stakeholders involved in project implementation. | |
| dc.description.abstract | Hutan mangrove merupakan bagian dari ekosistem karbon biru (blue carbon ecosystem) berperan penting dalam mitigasi perubahan iklim. Karbon dioksida (CO2) di atmosfer diserap dan digunakan dalam proses fotosintesis menghasilkan karbohidrat yang disimpan dalam bentuk biomasssa pada daun, batang, akar. Penyimpanan karbon juga terjadi di sedimen melalui dekomposisi bagian tumbuhan yang mati dan dari pasang surut, kemudian tersimpan dalam kondisi aneraob.
Mangrove menghadapi tantangan perubahan luasan disebabkan perubahan iklim global dan gangguan antropogenik. Dalam upaya memulihkan hutan mangrove, maka restorasi merupakan solusi berbasis alam yang berkontribusi bagi pembangunan berkelanjutan (SDGs). Penelitian dilakukan pada dua region, yaitu hutan mangrove region Jawa Timur (Kel. Mangunharjo, Desa Dringu) dan region Sumatera Utara (Desa Lubuk Kertang, Tanjung Rejo)
Penelitian memiliki 4 tujuan, yaitu: 1) menganalisis spesies penyusun hutan mangrove dan pengukuran faktor fisik-kimia tanah dan air; 2) kuantifikasi stok dan laju sekuestrasi karbon; 3) pemetaan pengaruh dna ketergantungan serta mobilisasi aktor terhadap tujuan; 4) mengestimasi nilai ekonomi karbon dari harga pasar sukarela. Stok karbon yang diukur merupakan hasil dari kuantifikasi hutan mangrove restorasi umur 8, 14 dan 20 tahun secara non destruktif. Umur 8 tahun dipilih karena kayu sudah memiliki xylem sekunder, sedangkan umur 14 tahun merupakan fase tengah dan umur 20 tahun fase klimaks. Alometrik biomassa yang digunakan adalah alometrik umum dengan dua parameter yaitu diameter (D) dan diameter-tinggi pohon (DT) pada dua kondisi: 1) ideal utuh (Di;DTi), yaitu seluruh pohon pada sub plot diasumsikan hidup; 2) aktual (Da;DTa), yaitu seluruh pohon didata sesuai dengan kondisi aktual, ada pohon yang hidup dan mati.
Komposisi spesies penyusun hutan mangrove Jawa Timur didominasi Rhizophora mucronata (INP 183,14%) kemudian R.stylosa (49,57%). Komposisi spesies penyusun Sumatra Utara di dominasi R. apiculata (INP 192,03%) dan R. mucronata (61,58%). Sifat fisik-kimia tanah mangrove tidak berbeda nyata pada nilai pH tanah yaitu rentang 3,8–6,0; kelembapan tanah 5,4–7,7; suhu tanah 25,3–31,0 °C; konduktifitas 3,5–4,0 mS/cm; suhu air 26,3–32,6 °C; TDS air 25,4–38,8; EC 37,8–59,60mS/cm; ORP 86,0 – 167,4; salinitas 24,9–41,8 ppt, dan BD tanah 0,81-1,03 g/cm3.
Nilai stok karbon rata-rata di Jawa Timur umur 8, 14 dan 20 tahun dengan alometrik (Di) berturut-turut 42,33±4,36, 70,97±11,87 dan 96,11±17,70 Mg C ha-1, sedangkan alometrik (Da) berturut-turut 41,79±4,11; 69,08±11,68 dan 93,08±17,03 Mg C ha-1. Nilai stok karbon rata-rata dengan alometrik (DTi) berturut-turut 43,47±5,74, 88,67±12,92 dan 116,13±22,66 Mg C ha-1, sedangkan alometrik (DTa) berturut-turut 43,06±5,59, 86,61±12,85 dan 113,93±22,05 Mg C ha-1. Nilai stok karbon rata-rata di Sumatera Utara umur 8, 14 dan 20 tahun (Di) berturut-turut 42,33±4,36, 70,97±11,87 dan 96,11±17,70 Mg C ha-1, sedangkan pada (Da) berturut-turut 41,79±4,11; 69,08±11,68 dan 93,08±17,03 Mg C ha-1. Nilai stok karbon rata-rata (DTi) berturut-turut 43,47±5,74, 88,67±12,92 dan 116,13±22,66 Mg C ha-1, sedangkan pada (DTa) berturut-turut 43,06±5,59, 86,61±12,85 dan 113,93±22,05 Mg C ha-1.
Total Karbon Ekosistem di Jawa Timur umur berada pada rentang 250,92 ±1,23 Mg C/ha hingga 390,02 ±7,28 Mg C ha-1. Sementara itu di Sumatera Utara rentang 289,66 ±3,86 Mg C ha-1 hingga 416,08 ±24,05 Mg C ha-1. Laju sekuestrasi karbon tahunan JT sebesar 18,40-19,82 Mg Mg CO2e ha-1 tahun-1 dan SU sebesar 49,97 -56, 02 Mg CO2e ha-1 tahun-1.
Peta pengaruh dan ketergantungan menunjukkan bahwa tata kelola restorasi mangrove di Jawa Timur dan Sumatera Utara memiliki pola umum yang serupa, yaitu didominasi oleh aktor pemerintah sebagai aktor penentu, didukung lembaga pendamping sebagai aktor penghubung, sementara aktor akademisi, pemerintah desa dan kecamatan masih berada pada posisi kurang aktif, termasuk kelompok masyarakat tapak. Mobilisasi aktor menunjukkan bahwa restorasi mangrove Jawa Timur dan Sumatera Utara sama-sama memperoleh dukungan positif tanpa penolakan eksplisit, tetapi prioritas mobilisasinya belum seimbang antara kepentingan ekologis dengan ekonomi dan sosial.
Estimasi NEK dengan rata-rata harga pasar sukarela global yaitu 30USD (1 USD: Rp17.000) pada mangrove restorasi di Jawa Timur dengan luasan 136,45 ha berada pada rentang Rp 408.065.338,- hingga Rp 551.618.532,- sedangkan pada mangrove restorasi di Sumatera Utara dengan luasan 2.221,18 ha pada rentang Rp 20.650.587.526,- hingga Rp 26.816.990.839,- dengan alokasi per hektarnya Rp 7.300.404,- untuk Jawa Timur dan Rp 22.552.772,- untuk Sumatera Utara. Tata cara laksana NEK sesuai Perpres 110/2025 dan Permenhut No. 6 Tahun 2026 bahwa manfaat ekonomi yang dihasilkan dari proyek karbon perlu dikelola melalui mekanisme benefit sharing yang adil, akuntabel, dan transparan, tidak hanya bagi investor atau pengelola proyek, tetapi bagi masyarakat, pemerintah, dan pihak yang terkait lainnya dalam proyek. | |
