Judul: Forest vegetation composition and structure of the former forest burned area (In R. Soerjo Forest Park Area, Malang)
Abstrak: I NTRODUCTION. Forests damage in Indonesia are increasing affect to forest function decline. One cause of forest destruction in Indonesia is forest fires. Forest fires in Indonesia are mostly caused by humans. Impact of forest fires covering all aspects of ecosystems like, vegetation, fauna, soil, water, climate, air, and humans. forest vegetation damage caused succession in burned area. Succession effect reflected on forest vegetation composition dan structure. METHODOLOGY. The research was conducted in unburnt forest area, forest areas with a mild fire level, forest area with medium fire level, and forest area with heavy fire level. In each site observations made in three plots with plot size 100 x 100 m. In each plot observations are made of 4 sub-plots sample with size 20 x 20 m to measure the level of tree, strangler and woody liana; size 10 x 10 m to measure the level of the pole; size 5 x 5 m measure the level of saplings, lianas non-wood, pine, and palm; and 2 x 2 m measure the level of seedlings, ferns, shrubs and herbs. RESULTS AND CONCLUSION. Forest fires in R Soerjo Forest Park, Malang resulted in a decrease number of species of trees and regeneration rate and growth form. Only herb that has a stable species number in all forest conditions. Shannon species diversity according to the Index of General Diversity (H') shows that forest fires reduced the value of diversity at the level of stakes, poles, trees and most other forms of non-tree growth. Forest structure in each forest condition have a different highest diameter class. Unburned forest conditions have diameter until up to 110 cm, mild level forest fires reached only 60-69 cm for the highest diameter class. Meanwhile, on the medium level forest fires reached 80-89 cm for the highest diameter class, while the diameter classes of forest with heavy fire levels only reached 40-49 cm. Forest fires reduce the value of density on all forest burned area. The effect of forest fire on soil chemical properties are decrease soil pH value, increase the value of C-organic, and increase the value of cation exchange capacity (CEC). Forest fire in R. Soerjo Forest Park Area, Malang is causing changes of forest vegetation composition and structure and also soil chemical properties.
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Judul: Composition and Vegetation Structure after Fire in the Peat Hydrologycal Unit (PHU) Meranti Island, Riau
Abstrak: Kebakaran berdampak pada perubahan komposisi jenis penyusun hutan, terutama pada hutan gambut yang memiliki ekosistem unik. Penelitian ini bertujuan untuk mengidentifikasi komposisi jenis di lahan pasca kebakaran pada perbedaan tahun kebakaran serta frekuensi kebakaran. Identifikasi area bekas kebakaran memanfaatkan indeks Normalized Burn Ratio (NBR) dan nilai difference Normalized Burn Ratio (dNBR). Data hotspot MODIS digunakan sebagai data pendukung area kebakaran serta dimanfaatkan sebagai penentuan periode kebakaran. Penelitian dilakukan di Kepulauan Meranti, Riau dengan pengumpulan data di lapangan menggunakan teknik purposive sampling pada kondisi hutan pasca kebakaran tahun 2014, 2018 dan 2019, serta 2020. Keanekaragaman jenis pada lahan pasca kebakaran tahun 2014 ditemukan 10 spesies, pada lahan pasca kebakaran keterulangan 2018 dan 2019 diperoleh 9 spesies, sedangkan pada lahan pasca kebakaran tahun 2020 ditemukan 7 spesies. Hasil suksesi pasca kebakaran hanya mencapai tingkat permudaan pancang. Tingkat tiang dan pohon yang ditemukan merupakan individu yang tahan terhadap kebakaran dan bukan merupakan hasil suksesi. Disisi lain, Asplenium sp. merupakan spesies tingkat tumbuhan bawah yang mendominasi di seluruh petak contoh.
Keyword: hotspot, kebakaran, lahan gambut, NBR, suksesi

Judul: Penyelesaian Masalah Rotasi Aliran Fluida Kental Von Karman Menggunakan Metode Homotopi
Abstrak: Von Karman equation is an equation that describes fluid viscous flow induced by infinite disk rotation. By assuming steady flow and laminar, viscous incompressible fluid flow is represented in Von Karman equation by an angular velocity and the vertical direction velocity as the independent variables. Von Karman equation is a nonlinear problem that is solved using the homotopy method. The use of homotopy method is done by defining an homotopy function that requires auxiliary parameters to control the convergent region of the solution. The solution is a recursive formula with given initial conditions. Using software based-functional shows that velocity components converge to a value.
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