Waru gunung (Hibiscus macrophyllus Roxb.) termasuk salah satu jenis kayu cepat tumbuh, namun data dan informasi mengenai kualitas kayu tersebut, terutama yang berhubungan dengan umur masih sangat terbatas sehingga pemanfaatannya belum optimal. Tujuan penelitian adalah untuk mengetahui kualitas kayu waru gunung pada tiga kelompok umur dan sifat densifikasinya untuk bahan mebel, sehingga dapat diperoleh gambaran tentang pengembangan kayu tersebut secara skala usaha. Penelitian ini menggunakan kayu waru gunung umur 8, 12, dan 16 tahun, masingmasing 2 pohon, dari Kabupaten Ciamis, Jawa Barat. Contoh uji diambil pada arah aksial: pangkal, tengah, ujung. Khusus untuk pengujian panjang serat, sudut mikrofibril (MFA), dan berat jenis (BJ) maka dari setiap batang aksial dibuat contoh uji arah radial: dari dekat empulur ke dekat kulit. Ukuran dan prosedur penelitian untuk uji panjang serat mengacu pada prosedur di Pusat Litbang Keteknikan dan Pengolahan Hasil Hutan, Bogor, MFA dengan Difraksi Sinar X (XRD), BJ dengan standar BS 373-1957, pengeringan dengan metode Terazawa yang dimodifikasi, pemesinan dengan ASTM D. 1666-64 yang dimodifikasi. Untuk kayu densifikasi digunakan scaning electron microscope (SEM) untuk uji perubahan struktur selnya, PY-GCMS untuk uji struktur kimia penyusun kayu, dan XRD untuk uji kristalinitas kayu. Data kemudian diuji secara statistik, ANOVA, regresi linear dan non linear. Hasil penelitian menunjukkan kualitas kayu waru gunung dipengaruhi oleh umur, posisi arah aksial, dan radial batang. Dari data panjang serat, MFA, dan BJ, diprediksi pembentukan kayu dewasa kayu waru gunung dimulai pada umur 11-13 tahun. Berdasarkan hasil penelitian ini hanya kayu umur 16 tahun dari batang pangkal-tengah yang memenuhi persyaratan untuk kayu mebel dilihat dari kestabilan dimensi (rasio penyusutan T/R < 2), BJ, kualitas pemesinan, dan nilai dekoratif kayu. Namun kayu umur 8 dan 12 tahun sudah memenuhi kriteria untuk bahan mebel setelah didensifikasi dengan tekanan 25 kg/cm2 selama 40 menit dengan suhu minimal 180oC.

Waru gunung (Hibiscus macrophyllus Roxb.) belongs to one of the fastgrowing trees species. However, data and information about the timber, particularly related to the tree ages, are still limited. As a result, utilization of waru gunung timber is still not yet optimal. This research aimed to look into the properties of that timber species at three different tree-age groups and its densification for furniture. In this way, the favorable depiction of that timber can expectedly be obtained regarding its development for endeavor scale. This research used waru gunung timber (wood) at three ages of 8, 12, and 16 years, each comprising two trees, obtained from Ciamis regency, West Java Province. The wood samples were prepared in axial direction of the tree stem, namely, bottom, middle, and top portions. Especially for the testing of fiber length, microfibril angle (MFA), and specific gravity (SG), from each of the axial stem samples were prepared in radial direction of the wood from pith to bark. Sample size and procedure to measure fiber length were referring to the procedure at the Center for Research and Development on Forestry Engineering and Forest Products Processing Bogor, MFA proceeded with the X-ray diffraction (XRD) methods, SG in accordance with the BS No 373-1957, the drying properties following the modified Terazawa method, and machining properties according to the ASTM No. D. 1666-64 (modified). Meanwhile, for the wood densification, it employed consecutively the scanning electron microscope (SEM) to scrutinize the possible changes in wood-cell structures, PY-GCMS for the testing of wood chemical components, and XRD for wood-cristallinity scrutiny. All the resulting data were processed using the descriptive statistics, analysis of variances, correlation assessment, and linear and non-linear regressions. Research results revealed that the properties of waru gunung wood were affected by tree ages, and position of the tree stem in axial as well as in radial directions. Assessment on the fiber length, MFA, and SG suggested that the development of mature wood began at tree ages about 11-13 years old. Judging from these research results, it turned out that only the wood with tree age of 16 years at the bottom and middle portions that could comply with the requirements for furniture wood as assessed on wood-dimensional stability (i.e. T/R ratio less than 2), SG, machining properties, and wood-decorative values. Nevertheless, the wood at tree ages of 8 and 12 years old could already satisfy the criteria for furniture wood, after being densified at 25 kg/cm2 pressure for 40 minutes employing the minimum temperature at 180oC.

Kata Kunci : kayu waru gunung, umur, kualitas kayu, densifikasi, mebel