Judul: Study of Gap Planting Impact to Soil Erosion on Rehabilitation Activities of Degraded Natural Forests in the PBPH Areal of PT SARPATIM
Abstrak: Pengembangan sistem silvikultur TPTR dan TRTR memerlukan informasi dampak tanam rumpang di areal hutan alam terdegradasi yang nantinya berdampak terhadap tanah hutan, terutama erosi tanah. Tujuan penelitian untuk mendapatkan informasi tingkat erosi tanah akibat kegiatan tanam rumpang di areal hutan alam terdegradasi serta bertopografi datar-landai dan sedang. Penelitian dilaksanakan pada Mei-September 2021 dengan pengambilan data sebanyak delapan kali di enam plot tanam rumpang dan enam plot hutan alam terdegradasi. Hasil uji statistik menunjukkan bahwa terdapat perbedaan nyata perlakuan teknologi tanam rumpang terhadap besar erosi tanah. Besar erosi tanah di rumpang bertopografi datar-landai dan sedang tidak berbeda nyata. Kesimpulan penelitian menunjukkan bahwa besarnya tanah tererosi yang terjadi berturut-turut dari terbesar ke terkecil ialah pada areal hutan alam terdegradasi, jalur tanam di rumpang, dan penyekat erosi di rumpang., The development of TPTR and TRTR silvicultural systems requires information on the impact of gap planting in degraded natural forest areals that might will have an impact on forest soils, especially soil erosion. The purpose of the research was to obtain information on the level of soil erosion due to the application of gap planting in degraded natural forest areals and with flat to sloping and moderate class topography. The research was carried out in May-September 2021 with data collection eight times in six gap planting plots and six degraded natural forest plots. The results of statistical tests showed that there were noticeable differences in the treatment of gap planting technology to the magnitude of soil erosion. Meanwhile, the magnitude of soil erosion in the gap flat to sloping topography and moderate topography did not show a noticeable difference. It is concluded, that the amount of eroded soil that occurred in order from the largest to the smallest was in the degraded natural forest areal, the planting stripe in the gap, and the erosion barrier in the gap.
Keyword: Degraded natural forests, Erosion, Gap planting technology, Rehabilitation

Judul: The Effect of Slopes on Soil Erosion in the Gap Planting Research Area of PT Sarmiento Parakantja Timber
Abstrak: Tanam Rumpang Tebang Rumpang (TRTR) merupakan sistem silvikultur yang diharapkan menjadi solusi peningkatan produktivitas hutan alam terdegradasi menggunakan teknologi tanam rumpang. Areal rumpang dimanfaatkan dengan menanam jenis pohon komersial setempat yang cepat pertumbuhannya dan berdaur pendek (5-8 tahun). Penelitian ini bertujuan untuk mengetahui pengaruh lereng terhadap erosi tanah yang terjadi akibat tanam rumpang. Penelitian dilakukan pada dua kelas lereng yakni kelas datar-landai dan kelas sedang. Hasil penelitian menunjukkan erosi tanah yang terjadi tertinggi pada areal simpukan, diikuti oleh erosi tanah di areal jalur tanam, dan yang terendah di areal hutan alam. Uji statistik menunjukkan bahwa erosi yang terjadi pada kondisi areal hutan alam, jalur simpukan dan jalur tanam tidak berbeda nyata. Pengaruh kelas lereng datar-landai dan kelas lereng sedang terhadap besarnya erosi di areal rumpang tidak berbeda nyata. Demikian pula besarnya erosi yang terjadi di areal rumpang dan di areal hutan alam terdegradasi juga tidak berbeda nyata., The gap planting and gap clear cutting (TRTR) silviculture system is projected to boost the productivity of damaged natural forests utilizing gap planting technology. The gap area is used by planting a local commercial fast-growing tree species with short-rotation (5-8 years). The goal of this study is to know how slopes affect soil erosion caused by gap planting. The study was conducted in two slope classes, namely the flat to sloping class and the medium class. The results showed that soil erosion occurred the highest in barrier areas, followed by soil erosion in planting path areas, and the lowest in natural forest areas. According to statistical analysis, there were no significant differences in the erosion that took place on planting path areas, barrier paths, and natural forest areas. The amount of erosion in the gap area is not considerably different depending on whether the slope is flat to sloping or medium. Similarly, the amount of erosion that occurs in the gap areas and in the degraded natural forest area is also not significantly different.
Keyword: Degraded natural forest, Gap planting, Soil erosion, Slopes

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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