Judul: The Carbon Dynamics in Rewetted Tropical Peat Swamp Forest
Abstrak: Extensive areas of tropical peat swamp forests (PSFs) have been deforested, degraded, and converted to other land uses. In degraded and drained conditions, the carbon emission is greater than the carbon sequestered, making this ecosystem a significant contributor to greenhouse gas (GHG) emissions from forestry and land-use sectors. Rewetting interventions as part of restoration management have been strongly recommended to mitigate the GHG emissions from degraded and drained tropical PSFs. GHG emission reductions or carbon benefits from the rewetting intervention is calculated by subtracting the GHG emissions from rewetted PSFs with GHG emissions from drained PSFs. Due to the lack of site-specific emission factors (EFs) from rewetted tropical PSFs, default EFs derived from Tier 1 methodology proposed by the Intergovernmental Panel on Climate Change (IPCC) have been widely used to quantify carbon benefit from the rewetting intervention in tropical PSFs. However, GHG emissions are not only affected by the climatic zone and soil nutrient status but also by the site-specific characteristics such as vegetation cover, previous land use, and restoration management being implemented. Therefore, the application of default EFs to a specific land cover could under- or over-estimate the carbon benefit, mainly if applied to a specific tropical PSF cover at the national and project levels. To assess this situation, we conducted a study with the intent of contributing to the restoration of tropical PSFs, particularly by providing site-specific GHG EFs for undrained and rewetted sites in tropical PSFs in Central Kalimantan Province, Indonesia. Both sites had been selectively logged prior being restored. The restoration was started in 2016. The study was divided into three phases: the first was a systematic review and meta-analysis of peer-reviewed literature and data, the second was an assessment of the study sites’ biophysical characteristics and carbon stocks, the third evaluated the variability of GHG EFs in the study sites. In the first phase (Chapter two), a review and meta-analysis were conducted to evaluate the effect of rewetting on carbon emissions by comparing the carbon emissions (CO2, CH4, and Dissolved Organic Carbon [DOC]) from rewetted peatlands (treatment sites) with drained peatlands (control sites) in various climatic zones and at different restoration times. Twenty-seven articles passed the inclusion criteria and were used for meta-analysis. Three of these articles were from tropical climates while the remainder were from boreal and, predominantly, temperate climates. The overall effect size indicates that peatland rewetting can reduce the CO2 emission rate by -1.343 ± 0.358 Mg CO2-C ha-1 yr-1, while significantly increasing the CH4 emission rate by 0.033 ± 0.003 Mg CH4-C ha-1 yr-1. However, there was no discernible effect of rewetting on DOC. The findings highlight the lack of primary data from rewetted tropical peatlands which indicates an opportunity to conduct more research on carbon emissions. In the second phase (Chapter three), biophysical characteristics, carbon stock, and fluxes of the study sites were assessed. The biophysical characteristics of both sites were not significantly different, except for the C/N ratio. The number of species per ha and basal areal in the undrained site were 78, and 23.2  3.1m2/ha While in the rewetted
Keyword: Carbon benefit, greenhouse gas, emission factors, meta-analysis, peatland restoration, heterotrophic respiration

Judul: Carbon Dynamics in Restored Secondary Tropical Peat Swamp Forests
Abstrak: Hutan lahan basah tropis sepeti halnya hutan rawa gambut secara global dikenal sebagai salah satu ekositem yang kaya akan karbon organik. Akan tetapi, hingga saat ini masih sedikit pemahaman mengenai siklus karbon di hutan rawa gambut, khususnya dalam hubungannya dengan perubahan tutupan lahan (misalnya akibat deforestasi, degradasi, dan aktivitas restorasi). Penelitian ini menyajikan data utuh tentang pemahaman dinamika karbon yang meliputi cadangan karbon ekosistem, produktivitas primer biomassa di atas permukaan, dan respirasi tanah gambut (respirasi total dan heterotrofik) serta tinggi muka air tanah di area restorasi hutan rawa gambut sekunder di Kabupaten Katingan, Provinsi Kalimantan Tengah. Dua plot permanen berukuran 100 m x 100 m dibangun di lokasi penelitian untuk pengamatan dan pengambilan data dinamika karbon secara sistematis dan reguler. Hasil pengamatan menunjukkan bahwa cadangan karbon ekosistem rawa gambut sekunder di lokasi studi ini adalah 1752 ± 401 ton karbon per hektar dimana 93% dari nilai tersebut tersimpan dalam bentuk tanah gambut. Nilai laju tahunan produktivitas primer biomassa dalam bentuk produksi serasah adalah 4.6 ± 0.5 ton karbon per hektar per tahun dan pertambahan biomassa dari pertambahan diameter batang pohon sebesar 2.7 ± 0.5 ton karbon per hektar per tahun dalam rentang 1.5 tahun pengamatan. Emisi karbon yang berasal dari respirasi heterotropik menyumbang sekitar 11.1 ± 0.9 ton karbon per hektar per tahun. Data hasil pengukuran lapang ini dikombinasikan dengan beberapa data literatur untuk estimasi nilai kesetimbangan karbon di ekosistem rawa gambut sekunder, yang meliputi produktivitas primer bersih, produktivitas primer bruto, dan respirasi ekosistem. Nilai produktivitas bersih primer hutan rawa gambut sekunder adalah sekitar 10.2 ton karbon per hektar per tahun, dimana lebih dari 75% dari total produktivitas primer bersih berasal dari pertambahan diameter batang dan produksi serasah. Estimasi nilai produktivitas primer bruto adalah 30.3 ton karbon per hektar per tahun. Secara keseluruhan, nilai kesetimbangan karbon di ekosistem rawa gambut sekunder ini adalah – 1.5 ton karbon per hektar per tahun, mengindikasikan bahwa karbon yang terlepas ke atmosfer lebih tinggi nilainya dibanding karbon yang masuk ke dalam ekosistem rawa gambut itu sendiri. Temuan ini diharapkan mendukung usaha pemerintah Indonesia dalam upaya konservasi dan restorasi hutan rawa gambut terdegradasi untuk strategi mitigasi perubahan iklim nasional
Keyword: biomass, fluxes, peatland, Indonesia, climate change mitigation

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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