Variasi Radial Sifat Fisika dan Keawetan Alami Kayu Kelapa (Cocos nucifera L.) yang Tumbuh di Kabupaten Bantul, Daerah Istimewa Yogyakarta

Achmad Rizal Mustaqim, Ir. Agus Ngadianto, S.Hut., M.Sc., Ph.D.

2026 | Tugas Akhir | D4 PENGELOLAAN HUTAN

Kayu kelapa (Cocos nucifera L.) merupakan tanaman yang berpotensi dimanfaat sebagai bahan baku alternatif pengganti kayu dalam mendukung pemanfaatan sumber daya secara berkelanjutan. Namun, pemanfaatannya masih terbatas karena informasi mengenai variasi radial sifat fisika dan keawetan alaminya masih terbatas. Penelitian ini bertujuan untuk menganalisis variasi radial sifat fisika dan keawetan alami kayu kelapa yang tumbuh di Kabupaten Bantul, Daerah Istimewa Yogyakarta menggunakan pemodelan efek campuran linier dan nonlinier. Hasil penelitian menunjukkan bahwa nilai rata-rata diameter batang dan tinggi pohon masing-masing sebesar 27,5 cm dan 13,3 m. Nilai rata-rata kerapatan dasar, kadar air segar, penyusutan radial, penyusutan tangensial, mortalitas rayap, kehilangan berat, dan kadar ekstraktif larut alkohol berturut-turut sebesar 0,54 g/cm³; 150,9%; 4,24%; 4,81%; 96,0%; 8,62%; dan 9,49%. Model efek campuran linier (Model I) merupakan model terbaik untuk menggambarkan variasi radial kerapatan dasar dan kadar air segar, sedangkan model efek campuran nonlinier logaritmik (Model II) merupakan model terbaik untuk menggambarkan variasi radial penyusutan radial, penyusutan tangensial, mortalitas rayap, kehilangan berat, dan kadar ekstraktif larut alkohol. Analisis korelasi menunjukkan bahwa kerapatan dasar berkorelasi negatif sangat signifikan dengan kadar air segar dan kehilangan berat akibat serangan rayap. Hasil penelitian menunjukkan bahwa kerapatan dasar berpotensi digunakan sebagai indikator awal untuk memprediksi kadar air segar dan kehilangan berat akibat serangan rayap, sehingga dapat mendukung penentuan kualitas dan ketahanan alami kayu kelapa.

Coconut wood (Cocos nucifera L.) has considerable potential as an alternative raw material to substitute conventional timber, thereby supporting the sustainable utilization of forest resources. However, its utilization remains limited due to insufficient information on the radial variation of its physical properties and natural durability. This study aimed to analyze the radial variation of the physical properties and natural durability of coconut wood grown in Bantul, Yogyakarta, using linear and nonlinear mixed-effects models. The results showed that the mean values of stem diameter and tree height were 27.5 cm and 13.3 m, respectively. The mean values of basic density, green moisture content, radial shrinkage, tangential shrinkage, termite mortality, mass loss, and alcohol-soluble extractive content were 0.54 g/cm³, 150.9%, 4.24%, 4.81%, 96.0%, 8.62%, and 9.49%, respectively. The linear mixed-effects model (Model I) was the best model for describing the radial variation in basic density and green moisture content, whereas the logarithmic nonlinear mixed-effects model (Model II) best described the radial variation in radial shrinkage, tangential shrinkage, termite mortality, mass loss, and alcohol-soluble extractive. Correlation analysis revealed that basic density was significantly and negatively correlated with green moisture content and mass loss caused by termite attack. These findings indicate that basic density has the potential to serve as an initial indicator for predicting green moisture content and mass loss due to termite attack, thereby supporting the assessment of the quality and natural durability of coconut wood.

Kata Kunci : Kayu kelapa, keawetan alami, sifat fisika, model efek campuran, variasi radial.