POLA DISTRIBUSI ABOVEGROUND BIOMASSA TEGAKAN MANGROVE DALAM KAITANYA DENGAN STOKS KARBON DI KAWASAN PESISIR SUNGAI PINYUH KABUPATEN MEMPAWAH KALIMANTAN BARAT

Mangrove ecosystem is one of the largest carbon storage sheds on earth, has enormous environmental benefits in disaster mitigation, as well as a source of livelihood for coastal communities. The purpose of this research is to know the aboveground biomass distribution of mangrove forest stand and to know the potency of carbon reserve of mangrove forest area of Mempawah Regency. The research was conducted from September to October 2017 in mangrove forest of Sungai Pinyuh district of Mempawah Regency. Aboveground biomass measurements are performed in a 50 x 50 m measuring plot, data collection is performed by listing each stand with dbh ? 5 cm and grouping it in diameter classes. Aboveground tree biomass estimation was performed using allometric equations and organic carbon stocks calculated by converting biomass by conversion factor of 0.5. The results showed the biomass value ranged from 32.37 to 55.84 tons / ha with an average value of 40.28 tons / ha. The highest biomass is distributed in diameter class 15-25 cm with the percentage 23.10% and lowest in class diameter> 55 cm with contribution equal to 13.39%. Carbon stock in mangrove stand biomass ranged from 16.18-27.91ton C / ha with average value 20.14 ton C / ha. Avicennia officinalis is an important type with the contribution of carbon reserves of 98.99%.Keywords: aboveground biomass, Carbon stock, mangrove forest, Mempawah Regency.AbstrakEkosistem mangrove merupakan salah satu gudang penyimpanan karbon terbesar di bumi, memiliki manfaat lingkungan yang besar dalam mitigasi bencana, serta sebagai sumber mata pencaharian masyarakat pesisir. Tujuan penelitian ini adalah untuk mengetahui distribusi aboveground biomass tegakan hutan mangrove dan mengetahui besarnya potensi cadangan karbon kawasan hutan mangrove Kabupaten Mempawah. Penelitian dilaksanakan dari bulan September hingga Oktober 2017 di hutan mangrove kecamatan Sungai Pinyuh Kabupaten Mempawah. Pengukuran biomassa atas permukaan (aboveground biomass) tegakan dilakukan di dalam petak ukur ukuran 50 x 50 m, pengumpulan data dilakukan dengan mendata tiap tegakan dengan dbh ? 5 cm dan mengelompokkannya dalam kelas-kelas diameter. Pendugaan biomassa aboveground pohon (aboveground tree biomass) dilakukan dengan menggunakan persamaan allometrik (Komiyama et al., 2008) dan stoks karbon organik dihitung dengan mengkonversikan biomassa dengan faktor konversi sebesar 0,5. Hasil menunjukkan nilai biomasa berkisar antara 32,37-55,84 ton/ha dengan nilai rata-rata 40,28 ton/ha. Biomasa tertinggi terdistribusi pada kelas diameter 15-25 cm dengan persentase 23,10% dan terendah pada kelas diameter >55 cm dengan kontribusi sebesar 13,39%. Stoks karbon pada biomasa tegakan mangrove berkisar antara 16,18-27,91 ton C/ha dengan nilai rata-rata 20,14 ton C/ha. Avicennia officinalis merupakan jenis penting dengan kontribusi stoks karbon sebesar 98,99%.Kata kunci: Aboveground biomass, hutan mangrove, Kabupaten Mempawah, Stok karbon.

Short-Term Dynamics of Vegetation Diversity and Aboveground Biomass of Picea abies (L.) H. Karst. Forests after Heavy Windstorm Disturbance

Although forest disturbances have become more frequent and severe due to ongoing climate change, our understanding of post-disturbance development of vegetation and tree–herb layer interactions remains limited. An extreme windstorm, which occurred on 19 November 2004, destroyed Picea abies (L.) H. Karst dominated forests in the High Tatra Mts. Here, we studied short-term changes in diversity, species composition, and aboveground biomass of trees and herb layer vegetation, including mutual relationships that elucidate tree–herb interactions during post-disturbance succession. Assessment of species composition and tree biomass measurements were performed at 50 sample plots (4 × 4 m) along two transects 12, 14, and 16 years after the forest destruction. Heights and stem base diameters of about 730 trees were measured and subsequently used for the calculation of aboveground tree biomass using species-specific allometric relationships. Aboveground biomass of herb layer was quantified at 300 subplots (20 × 20 cm) by destructive sampling. Species richness and spatial vegetation heterogeneity did not significantly change, and species composition exhibited small changes in accordance with expected successional trajectories. While aboveground tree biomass increased by about 190%, biomass of annual herb shoots decreased by about 68% and biomass of perennial herb shoots was stable during the studied period. The contribution of trees to total aboveground biomass increased from 83% to 97%. After 16 years of forest stands recovery, tree biomass represented approximately 13% of forest biomass before the disturbance. Herb layer biomass, particularly the biomass of annual herb shoots, was more closely related to tree cover than to tree biomass and its decline could be assigned to gradual tree growth. Our study provides clear evidence that short-term successional processes in post-disturbance vegetation are much better detectable by biomass than by diversity or compositional measures and emphasized the importance of light conditions in tree–herb competitive interactions.

Estimation of aboveground tree biomass Toona sureni and Coffea arabica in agroforestry system of Simalungun, North Sumatra, Indonesia

Latifah S, Muhdi, Purwoko A, Tanjung E. 2018. Estimation of aboveground tree biomass Toona sureni and Coffea arabica in agroforestry system of Simalungun, North Sumatra, Indonesia. Biodiversitas 19: 620-625. Agroforestry is an ecologically and environmentally sustainable land use that offers great promise to carbon (C) sequestration. Forests play a significant role in reducing greenhouse gas emissions through maintaining current carbon stores and by increasing the rate of carbon sequestration. Vegetation carbon stocks are necessary to be quantified to evaluate the carbon sequestration potential in the ecosystem. Reasonable methods for estimating tree biomass and carbon storage on forest land are increasingly crucial given concerns of global climate change. This study aimed to evaluate C sequestration potential by agroforestry in North Sumatra Indonesia. This study was conducted at the Agroforestry system in Aek Nauli, Simalungun District, North Sumatra. Data collection for primary data was done through a field survey. The present study was carried out to determine above ground tree biomass of Toona sureni (Blume) Merr and Coffea arabica. Data retrieval of T. sureni and C. arabica was done by non-destructive sampling by measuring the diameter at breast height (dbh). The results showed that the potential of average above-ground biomass and carbon storage of T. sureni and C. arabica was 6.25 t ha-1 and 2.88 C t ha-1, respectively. Total aboveground biomass of Toona sureni and C. arabica in the study area was 93.75 ton, while total of carbon storage was 43.16 ton