Judul: Model Struktur Tegakan Hutan Tanaman Agathis (Agathis loranthifolia) di Hutan Pendidikan Gunung Walat Sukabumi Jawa Barat
Abstrak: Forest stand structure is the number of trees distribution on various class diameters per unit area and is one of the forms of display of a structure. A diversity of various class diameters are very affected by external and internal factors of tree development. The internal factors that affect : tree growth are types and location of tree developments. Tree types are highly linked with genetic factors, few trees with the same types but different surrogates, then those trees will have different growth for each trees. Meanwhile, the age of tree is linked with diameter growth, the age difference will affect the large or small of the diameter. The external factors that affects tree growth are climatic factor, edapic factor, and biotic. The edapic factor is connected with the soil which is the growth place’s condition. The condition of the said forest stand structur essentially can be identified by looking at the stand structure of the forest. To elaborate the stand structure condition, a famillial distribution method such as : normal distribution family, lognormal, gamma, and negative exponential can be used. The purpose of this study is to gain an agathis plant forest stand structure model in the shape of its family’s distribution, as well as analyzing the skewness value of Agathis loranthifolia’s stand stucture curve. This research was conducted at Gunung Walat University Forest in February 2011. The data used were the tree measurement on breast height of agathis forest stand. The method used to measure the stands was the lines method. The transect chosen is 1 hectare area wide with a 500 meter line length and 20 meter line width. The choosing of the transect location is conducted by purposive sampling. In this research, five transects is chosen that is able to represent the forest stand structure in the study location. The results of study conducted in Gunung Walat University Forest with maximum likelihood function method indicates that the model choosen as the best model in depicting the stand stucture of the agathis cohort and the cohort of all types is the gamma family distribution model. Meanwhile, the best model in depicting the cohort stand structure of types is the lognormal distribution family model. The coefficient skewness value obtained tends towards positive skewness. This indicates that most of the data clusters in the left side end, while in the right side end, the data isn’t that many. So that in its management it will be easier to make the curve to zero skewness by doing regeneration effort by planting on unproductive areas or empty lots, efforts in increasing quality and quantity by thinning, controlling pests and disease, controlling forest fires, climate disturbance, and protecting from disturbances from humans and animals.
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Judul: Studi model struktur tegakan hutan tanaman pinus merkusii Jungh et de Vriese tanpa penjarangan di Hutan Pendidikan Gunung Walat
Abstrak: Forest stand condition is influenced by habitat condition, silvicultur treatments, age and genetic properties of trees, the interaction between each individual tree to habitat condition, and also interactions among individual trees. Effective influence of these factors will make a forest stands into the condition which very typical in any particular area. In essence, the forest stand condition may be known by looking at its stand structure. To explain the structural condition of stands, it can use family distribution models, such as the normal family distribution, lognormal, gamma, and negative exponential. This research aims to obtain the stands structure model of pine (Pinus merkusii Jungh et de Vriese) plantation forest on the family distribution, and analyze its curve skewness coefficient value. This research was conducted at Gunung Walat University Forest in August 2010. The data used were the tree diameter measurement on breast height of P. merkusii plantation forest which the age is unknown. The sample method is purposive line or strip sampling. The sensused plots were about 1 hectare with 500 m length path and 20 m wide path. The plots location was selected through purposive sampling method. In this research, five plots which were considered for representing the structure of forest stands at the sites would be taken. The results of research were conducted at Gunung Walat University Forest by using the maximum likelihood function shows that the family distribution model which was chosen as the best family distribution model for describing the stand structure of pine species and all species was the gamma family distribution, while for other species was the lognormal family distribution. Meanwhile, the skewness coefficient value which obtained tends on positive skewness, which means that curve is right skewed. The information of forest stand condition can be a suggestion to determine silviculture implementation, specially for thinning and felling, to get the expected forest stand condition.
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Judul: Penentuan energi aktivasi ion untuk melewati membran teflon pada berbagai larutan elektrolit
Abstrak: Kaseno (1999) menyatakan bahwa dalam teknologi pemisahan, membran adalah bahan yang dapat memisahkan dua komponen dengan cara yang spesifik yaitu menahan atau melewatkan salah satu komponen lebih cepat dari komponen lainnya. Kemampuan pemisahan yang dimiliki oleh membran untuk melewatkan suatu senyawa kimia atau molekul diakibatkan oleh adanya perbedaan sifat fisika atau kimia antara membran dengan senyawa kimia.
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