Variasi aksial dan radial sifat fisika-mekanika dan struktur anatomi kayu jabon (anthocephalus cadamba Miq) dari Kabupaten Landak Kalimantan Barat

YANI, Ahmad, Dr. Ir. Sri Nugroho Marsoem, M.Agr

2009 | Tesis | S2 Ilmu Kehutanan

Studi variasi aksial dan radial sifat fisik-mekanik dan struktur anatomi kayu jabon dilakukan menggunakan tiga pohon dengan diameter stinggi dada (dbh) rata-rata 36 cm. Ketiga pohon tersebut tumbuh di hutan rakyat di Kabupaten Landak, Kalimantan Barat. Contoh uji kayu di dalam batang di ambil berdasarkan pada kedudukan aksial dan radial. Pengambilan log kayu sepanjang 110 cm dipotong pada bagian batang dari pangkal ke ujung sampai batas cabang pertama. Pengujian sifat fisik; kadar air, berat jenis dan perubahan dimensi, sifat mekanik; keteguhan lengkung statis dan keteguhan tekan, dan strutur anatomi; proporsi sel, dimensi serat dan sudut mikrofibril. Data dianalisa dengan analisis varians yang menggunakan Rancangan Acak Lengkap dalam Faktorial. Penelitian ini bertujuan untuk mengetahui variasi aksial dan radial sifat fisikmekanik dan struktur anatomi kayu jabon yang terdapat di Kabupaten Landak Kalimantan Barat untuk kemungkinan penggunaan yang sesuai. Hasil penelitian menunjukkan bahwa kayun jabon mempunyai rerata kadar air segar dan kering udara sebesar 93,76 % dan 14,13 %. Berat jenis segar, kering udara dan kering tanur sebesar 0,27, 0,28 dan 0,30. Penyusutan tangensial, radial dan longitudinal dari segar ke kering udara sebasar 4,66, 0,99 dan 0,29, dengan nilai perbandingan T/R 4,90. Pengembangan tangensial, radial dan longitudinal dari kering tanur ke basah sebesar 7,97, 2,34 dan 0,51, dengan perbandingan T/R 3,54. Keteguhan lengkung statik sampai batas proporsi (BP), MOE dan MOR sebasar 145,07 kg/cm2, 41,45 ( x 1000 kg/cm2) dan 424,54 kg/cm2. Keteguhan tekan sejajar serat sampai modulus young (MOY) dan sampai maksimum sebesar 1,36 ( x 1000 kg/cm2) dan 90,66 kg/cm2, dan keteguhan tekan tegak lurus serat sampai maksimum sebesar 60,84 kg/cm2. Proporsi sel pembuluh 9,39 %, serabut 55,32 %, jari-jari 17,56 % dan parenkim 18,43 %. Panjang serat 1,46 mm, diameter serat 27,23 μm, diameter lumen 22,42 μm dan tebal dinding sel 2,40 μ. Sudut mikrofibril rerata sebesar 30,01o. Secara umum pola penyebaran sifat fisik-mekanik dan struktur anatomi kayu jabon pada arah aksial dan radial yang terbentuk sangat bervariasi. Kayu jabon dapat digunakan untuk konstruksi ringan dan cocok untuk bahan baku pulp dan kertas.

Study on axial and radial variation of physical-mechanical properties and anatomical structure of jabon tree were conducted by using three trees of jabon with diameter breast height (dbh) average about 36 cm. the trees of jabon were grown in community forest in landak sub province west Kalimantan. Wood sample due to the trunk were based on axial and radial position. Log with 110 cm length was cut at bottom section to the top section of the first branch of the trunk. Moisture content examination, specific gravity and dimensional changes, were conduct as physical examination. The examination of Static bending strength, compression strength and anatomical structure, cell proportion, fiber dimension and micro fibril angel. Data obtained were analyzed by analysis of variance by using a factorial experimental in Completely Randomized Design. This research aim is to know axial and radial variation of physicalmechanical properties and anatomical structure of Jabon that grown in Landak sub province west Kalimantan for determination the possible utilization. The research result showed that jabon have the average of green and air -dry moisture content are 93.76 % and 14.13 % respectively. The specific gravity of green, air-dry and oven-dry are 0.27, 0.28 and 0.30 respectively. Tangential, radial and longitudinal shrinkage from green to air–dry are 4.66, 0.99 and 0.29 respectively with T/R ratio is 4,90. Tangential, radial and longitudinal swelling from green to air-dry are 7.97 , 2.34 and 0.51 respectively with T/R ratio is 3.54. Static bending strength till the proportion limit , MOE and MOR are 145.07 Kg/cm2, 41.45 (x 1,000 Kg/cm2) and 424.54 Kg/cm2 respectively. Compression strength parallel to grain till modulus of young and maximum are 1.36 (x1,000 kg/cm2) and 90.66 kg/cm2. The proportion of wood vessels is 9.39 %, fibers 55.32 %, rays 17.56 % and parenchyma is 18.43 %. Fiber length is 1.46 mm, fiber diameter is 27.23 μm, cell wall thickness is 2.40μm. the average of micro fibril angel is 30.010. Generally, distribution pattern of physical-mechanical properties and anatomical structure of Jabon at axial and radial were formed vary. Jabon is can be used to light construction and suitable for pulp and paper raw material.

Kata Kunci : Jabon (Anthocephalus cadamba Miq),Sifat fisik,Sifat mekanik,Struktur dan anatomi kayu serta sudut mikrofibril