Variasi Radial Sifat Kayu Puspa Hutan Tanaman serta Transisi Kayu Juvenil dan Kayu Dewasanya

Abstract

Karakteristik dan keseragaman mutu kayu dalam sepotong sortimen (kayu gergajian) sangat mempengaruhi tujuan akhir penggunaan dan mutu produk yang akan dihasilkan. Penelitian ini bertujuan untuk menganalisis variasi radial beberapa sifat kayu puspa hasil hutan tanaman umur 56 tahun dan mengevaluasi keseragaman mutunya dalam sebatang pohon. Sifat yang diteliti terdiri dari kerapatan kayu, panjang serat dan sudut mikrofibril (MFA), sedangkan keseragaman mutu kayu dievaluasi berdasarkan keberadaan kayu juvenil dan kayu dewasa. Kerapatan kayu diukur secara gravimetris, panjang serat melalui sediaan maserasi, sedangkan MFA melalui sediaan mikrotom. Transisi kayu juvenil dan kayu dewasa ditetapkan secara visual berdasarkan variasi radial nilai ketiga parameter yang diteliti dari empulur ke kulit. Hasil penelitian memperlihatkan bahwa kerapatan, panjang serat dan MFA kayu puspa bervariasi dari empulur ke kulit. Rata-rata nilai kerapatan kayu adalah 0,76 g/cm3 , panjang serat 1328 μm dan rata-rata MFA 43,04⁰. Meskipun transisi kayu juvenil dan kayu dewasa belum dapat dipastikan keberadaannya, namun periode pembentukan kayu juvenil akan berakhir pada segmen ke-4 atau 8 cm dari empulur. Kata kunci: Juvenilitas, kerapatan kayu, panjang serat, Schima wallichii, sudut mikrofibril

The characteristics and uniformity of wood quality in a piece of sortimen greatly influence the final use and the quality of the product to be made. This study aims to analyze the radial variation of several properties of 56-year-old puspa wood from plantation forest, and to evaluate the uniformity of wood quality within a single tree. The properties studied consisted of wood density, fiber length and microfibril angle (MFA), while the uniformity of wood quality was evaluated based on the presence of juvenile and mature wood. Wood density was measured gravimetrically, fiber length through maceration specimens, while MFA through microtome specimens. Juvenile-mature wood transition was determined visually based on radial variation of the three parameters studied. The results showed that density, fiber length and MFA of puspa wood varied from pith to the bark. The average wood density is 0,76 g/cm3 , fiber length is 1328 μm and the MFA is 43,04⁰. Although the transition between juvenile and mature wood is still unknown, it is certain that juvenile wood formation period will end at the 4th segment or 8 cm from the pith. Kata kunci: Fiber-length, juvenility, microfibril angle, Schima wallichii, wood density.