Judul: Systematic Review: Timber Harvesting Waste in Indonesia (Quantity, Source, and Utilization)
Abstrak: Pemanfaatan kayu yang kurang efisien terjadi karena jumlah kayu yang dimanfaatkan pada umumnya masih rendah dibandingkan dengan volume kayu yang ditebang. Dalam arti lain, kegiatan pemanenan masih banyak menimbulkan limbah kayu. Penelitian mengenai limbah pemanenan kayu sudah banyak dilakukan di Indonesia. Penelitian ini bertujuan untuk menghimpun dan menganalisis hasil penelitian terkait kuantitas, sumber, dan pemanfaatan limbah pemanenan kayu di Indonesia. Penelitian ini menggunakan data sekunder yang dihimpun menggunakan metode systematic review yang kemudian dilakukan analisis secara deskriptif. Hasil pencarian secara online mendapatkan 32 artikel penelitian mengenai limbah pemanenan kayu di Indonesia dari tahun 1984 hingga tahun 2020 yang terbagi atas dua jenis hutan, yaitu hutan alam dan hutan tanaman. Penelitian paling banyak dilakukan di hutan alam dengan teknik pemanenan yang digunakan adalah Reduce Impact Logging (RIL) dan konvensional. Limbah kayu berupa tunggak merupakan jenis yang paling banyak dihasilkan dengan kondisi cacat mekanis berupa pecah. Keterampilan operator chainsaw, topografi, kelas umur pohon, diameter pohon, kerapatan tegakan, dan penentuan arah rebah pohon sangat memengaruhi limbah kayu yang terjadi dalam kegiatan pemanenan kayu., Inefficient use of wood occurs because the amount of wood used is generally still low compared to the volume of wood cut. In another sense, harvesting activities still generate a lot of wood waste. Research on wood harvesting waste has been widely carried out in Indonesia. This study aims to collect and analyze research results related to the quantity, source, and utilization of wood harvesting waste in Indonesia. This research uses secondary data collected using a systematic review method which is then analyzed descriptively. The online search results found 32 research articles on wood harvesting waste in Indonesia from 1984 to 2020 which were divided into two types of forest, namely natural forest and plantation forest. Most research is conducted in natural forests with the harvesting techniques used are Reduce Impact Logging (RIL) and conventional. Wood waste in the form of stumps is the type that is mostly produced with mechanical defects in the form of breaking. The skills of chainsaw operators, topography, tree age class, tree diameter, stand density, and determining the direction of tree fall greatly affect the wood waste that occurs in wood harvesting activities.
Keyword: harvesting waste, harvesting waste wood, wood waste.

Judul: Systematic Review: Environmentally Friendly Forest Harvesting in Indonesia.
Abstrak: Tinjauan Sistematis: Pemanenan Hutan Ramah Lingkungan di Indonesia. Dibimbing oleh AHMAD BUDIAMAN. Pemanenan kayu pada pengelolaan hutan alam masih menimbulkan permasalahan lingkungan. Teknik perencanaan serta pelaksanaan pemanenan kayu yang baik dan benar masih belum dipergunakan dalam pemanenan kayu di hutan alam Indonesia, sehingga dampak kerusakan yang ditimbulkan selama kegiatan pemanenan kayu masih tinggi. Tujuan penelitian ini yaitu untuk mengetahui dan menghimpun hasil penelitian mengenai pemanenan hutan ramah lingkungan berdampak rendah serta mengevaluasi kinerja teknik Reduced Impact Logging. Penelitian ini menggunakan metode systematic review. Jenis data yang dikumpulkan berupa artikel berbahasa Indonesia maupun Inggris, yang bersifat open access sebanyak 28 jurnal. Hasil penelitian menunjukkan bahwa pemanenan kayu konvensional yang dilaksanakan selama ini dilakukan tanpa perencanaan yang baik, teknik pelaksanaan yang buruk dan lemahnya pengawasan menyebabkan kerusakan lingkungan yang besar, sedangkan pemanenan kayu dengan teknik Reduced Impact Logging lebih banyak disarankan untuk digunakan dalam kegiatan pemanenan hutan di berbagai Negara karena bersifat ramah lingkungan dan mampu meminimalkan kerusakan yang terjadi., Systematic Review: Environmentally Friendly Forest Harvesting in Indonesia. Supervised by AHMAD BUDIAMAN. Timber harvesting in natural forest management still causes environmental problems. Planning techniques and the implementation of good and correct timber harvesting are still not used in timber harvesting in Indonesia's natural forests, so the impact of damage caused during wood harvesting activities is still high. The purpose of this study is to find out and collect the results of research on environmentally friendly forest harvesting with a low impact and evaluate the performance of the Reduced Impact Logging technique. This study used the systematic Reviu method. The type of data collected is in the form of Articles in Indonesian and English, which are open access as many as 28 journals. The results showed that conventional wood harvesting carried out so far was carried out without good planning, poor implementation techniques and weak supervision caused great environmental damage, while wood harvesting with the Reduced Impact Logging technique was more widely recommended to be used in forest harvesting activities in various countries because it is environmentally friendly and able to minimize the damage that occurs.
Keyword: conventional, low impact harvesting, reduced impact logging, sustainable forest harvesting

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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