Judul: Systematic Review: Techniques, Produvtivity, and Costs of Harvesting Forest in Indonesia
Abstrak: Pasokan kayu selama ini berasal dari hasil pemanenan hutan alam dan hutan tanaman. Penelitian mengenai pemanenan kayu sudah banyak dilakukan di Indonesia dengan variasi hasil yang berbeda. Penelitian ini bertujuan untuk menghimpun hasil penelitian mengenai teknik, produktivitas, dan biaya pemanenan hutan di Indonesia. Data sekunder dihimpun menggunakan metode Systematic Review kemudian dianalisis menggunakan analisis deskriptif. Berdasarkan hasil pencarian secara online terhimpun 51 artikel penelitian mengenai pemanenan kayu di Indonesia yang kemudian dikelompokan menjadi tiga tipe hutan yaitu, hutan tanaman lahan basah, hutan tanaman lahan kering, dan hutan alam. Hutan tanaman lahan kering merupakan jenis hutan yang paling banyak diteliti. Kegiatan pemanenan dibagi menjadi beberapa tahapan antara lain penebangan, penyaradan, muat bongkar, dan pengangkutan. Kegiatan yang paling banyak diteliti adalah penyaradan. Produktivitas pemanenan dipengaruhi oleh peralatan pemanenan, kondisi lapang, teknik pemanenan, keterampilan pekerja, beban kerja, dan cuaca. Besarnya biaya pemanenan di pengaruhi oleh produktivitas, biaya pemilikan, biaya operasional, dan upah pekerja., The supply of wood so far has come from harvesting natural forests and plantation forests. Many studies on timber harvesting have been carried out in Indonesia with varying results. This study aims to compile research results on techniques, productivity, and costs of forest harvesting in Indonesia. Secondary data was collected using the Systematic Review method and then analyzed using descriptive analysis. Based on the results of an online search, 51 research articles on timber harvesting in Indonesia were collected which were then grouped into three types of forest, namely, wetland plantation forest, dry land plantation forest, and natural forest. Dryland plantation forest is the most studied forest type. Harvesting activities are divided into several stages, including logging, skidding, loading and unloading, and transportation. The most researched activity is skidding. Harvesting productivity is influenced by harvesting equipment, field conditions, harvesting techniques, worker skills, workload, and weather. The amount of harvesting costs is influenced by productivity, ownership costs, operational costs, and worker wages.
Keyword: biaya pemanenan, produktivitas pemanenan kayu, teknik pemanenan

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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