Judul: Evaluasi Awal Uji Keturunan Kayu Manii (Maesopsis eminii Engl.) Umur 5 Tahun
Abstrak: Maesopsis eminii is a fast growing tree species commonly found in community-forest. Due to its economic and ecological significance, breeding program of this species has been initiated. The objectives of this research were: i) to estimate the genetic parameters of the progeny trial including genetic gain and ii) to determine correlation between wood quality traits (based on non-destructive test) and growth traits. Randomized Complete Block Design (RCBD) were used consisting of 100 families replicated in 8 blocks for evaluating growth traits and their associated genetic parameters (Experiment-I), while Completely Randomized Design (CRD) with 3 treatments, i.e. fast, moderate and slow tree growths and 16 replicates were used for determining wood quality traits (Experiment-II). There was a fluctuation in terms of values of genetic parameters; it was high during the early growth, significantly decreased in the middle, then increased and reached stability at later growth stages. Consistencies of genetic parameters value (H2 and rg) were given by growth increments 41 and 56 months, namely: ΔD41, ΔT41, ΔV41 and ΔD56, ΔT56, ΔV56. Highest genetic gain (ΔG) was expected by ΔD56 - ΔV56 (14.2%) based on indirect selection method. A negative correlation between a wood quality trait (MOEd) and a growth trait (tree volume) was observed with a value of (r = -0.246). The results also would imply that the recommended genetic selection, i.e. roguing, that is best carried out by using indirect-method based on measurement of diameter (dbh) as main criteria.
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Judul: Evaluasi Kualitas Pertumbuhan dan Karakteristik Kayu Jati (Tectona grandis L. f.) Unggul Nusantara Umur 4 Tahun
Abstrak: INTRODUCTION. The lack of better quality of wood supply recently has resulted in the barrier of wood industry development in Indonesia. To overcome the above problem many community forests had been establishing by people using selected wood species. One of them is Jati (Tectona grandis) Unggul Nusantara (JUN) plantation belongs to Koperasi Perumahan Wanabakti Nusantara (KPWN) with teak as the main species. These stands were planted using tree spacing of 3 m by 3 m for the rotation of 5 years. To ensure these woods qualities were similar to those of the conventional teak, growth quality and wood properties have to be studied well. The aim of the study was to evaluate growth quality and wood characteristics of 4 year-old JUN by measuring the diameter and height of the trees and by studying wood physic properties and fiber morphology. MATERIALS AND METHOD. The main material used was increment core of 4 year-old of JUN extracted from the stem from the nine selected trees representing the diameter of the stands (small, medium and big) at dbh level using increment borer (ø 5 mm). From each sample tree, 2 pieces of increment core were extracted oppositely: one for wood physical measurement (moisture content at green condition/green MC, wood density and specific gravity/SG); and the other for fiber morphology measurement (fiber length and cell wall thickness). Both of them were measured radially (from pith to the bark). All measurements were carried out using procedural standard of Faculty of Forestry IPB. Demarcation between juvenile- and mature wood portions was evaluated using fiber length and wood density from pith to the bark. Effect of stem diameter and growth ring number was evaluated using t-student at the 95% confidence interval. Data processing was conducted with SPSS 13. RESULT AND DISCUSSIONS. It showed that growth quality of JUN was varied. Average value of diameter and height was 13.45 cm and 6.92 m, respectively. Growth rate of diameter and height was fast. They are around 3.36 cm and 1.73 m per year, respectively. It also showed that green MC, density, SG, fiber length and cell wall thickness of each group were varied. Average value of green MC was 112.27% (small tree), 127.53% (medium) and 146.35% (big); wood density was 0.99 g/cm3 (small), 1.02 g/cm3 (medium) and 1.09 g/cm3 (big); SG was 0.47 (small), 0.45 (medium) and 0.45 (big); fiber length was 741.15 μm (small), 845.52 μm (medium) and 833.30 μm (big), while wall thickness was 3.06 μm (small), 3.20 μm (medium) and 3.17 μm (big). Statistical analysis showed that green MC and wood density are influenced by diameter, while SG, fiber length and cell wall thickness are not. The bigger the diameter, the greater the green MC and the wood density. Based on its SG, the wood of JUN was classified into Strength Class of III. The result also showed that growth ring has no effect on the all parameters studied, except in case of SG on medium tree group and fiber length on small tree group. Generally, SG and fiber length tended to increase from pith to the bark.
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Judul: Persamaan Gelombang Permukaan Dalam Sistem Hamiltonian
Abstrak: Fluida adalah suatu zat yang bentuknya dapat berubah secara kontinu akibat gaya geser. Dua bentuk fluida yang dikenal adalah fluida yang berbentuk cairan dan gas. Dalam tulisan ini akan dibahas fluida yang berbentuk cairan. Persamaan yang memodelkan fenomena gelombang fluida di antaranya adalah sistem Hamiltonian. Persamaan ini berasumsi babwa fluida dalam keadaan ideal di mana fluida tak mampu mampat (inkompresibel), fluida tak rotasional (irrotasional).
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