Variasi Keawetan Alami Kayu Surian (Toona sinensis Roem.) dalam Sebatang Pohon

Abstract

Surian (Toona sinensis) merupakan salah satu pohon cepat tumbuh yang banyak ditemukan di Indonesia. Kayunya sudah dijadikan komponen perahu, rumah dan meubel meski baru diperdagangkan secara lokal. Variasi keawetan alami kayu surian masih belum banyak diketahui. Penelitian ini bertujuan mempelajari variasi vertikal dan variasi radial keawetan alami kayu surian dalam satu batang pohon untuk menentukan tindakan pengawetan yang harus diambil dalam rangka pemanfaatan kayu secara maksimal. Contoh uji berupa kayu surian yang mewakili bagian pangkal-tengah-ujung (variasi vertikal atau faktor ketinggian) dan gubal peralihan-teras (cariasi radial atau faktor kedalaman) dalam batang. Sebagai pembanding digunakan kayu pinus. Keawetan alami dievaluasi berdasarkan kehilangan berat dan kerusakan contoh uji setelah dikubur 3 bulan. Hasil penelitian menunjukkan keawetan alami kayu bervariasi menurut ketinggian dan kedalaman batang. Keawetan alami cenderung berkurang dari pangkal ke ujung batang mau pun dari teras ke gubal. Kehilangan berat dipengaruhi oleh faktor ketinggian dan kedalaman, sedangkan kerusakan contoh uji dipengaruhi oleh faktor ketinggian, kedalaman dan interaksi keduanya. Keawetan alami kayu surian secara keseluruhan lebih baik dibandingkan kayu pinus.

Surian (Toona sinensis) is one of the fast-growing tree species found in Indonesia. The wood is already used locally as a component for boats, houses and furniture. Since variations in natural durability of this wood are still limited, it is necesary to conduct a study on this aspect. This study aims to investigate variations in natural durability of surian wood, especially from a single tree, both vertical and radial directions in order to determine proper preservative treatment. The test sample was surian wood which represents the bottom-middle-tip as well as the heartwood transition-sapwood. As a comparison, pine wood was utilized. Natural durability of wood was evaluated based on weight loss and damage percentage in cross-section of wood samples after being buried for 3 months. Results showed that natural durability of this wood varies in vertical and radial directions. It tends to decrease from the bottom to the tip of the trunk and from pith (heartwood) to the bark (sapwood). The weight loss percentage was influenced by the height and depth factors, while the damage was influenced by the height, depth and the interaction of these two factors. Overall, natural durability of surian wood is better than that of pine wood.