Pengawetan Kayu Gubal Jati Secara Rendaman Dingin dengan Pengawet Boron untuk Mencegah Serangan Rayap Kayu Kering (Cryptotermes cynocephalus Light.)

Abstract

Pada penggunaan kayu jati umur muda, umum diketahui bahwa bagian gubal banyak diserang oleh rayap kayu kering karena keawetan alaminya yang rendah. Asam borat dan boraks merupakan salah satu pengawet yang mengandung bahan aktif boron yang murah, mudah didapat, tidak berbau, dan tidak mengubah warna kayu. Bahan yang digunakan adalah bagian gubal papan jati yang diperoleh dari tebangan jati hutan rakyat di Kecamatan Kali Bawang, Kulon Progo. Penelitian ini menggunakan rancangan acak lengkap yang disusun secara faktorial dengan dua faktor yaitu faktor jenis bahan pengawet yaitu asam borat dan boraks (konsentrasi 5 %) dan faktor lama perendaman (12, 24, 36, dan 48 jam). Rayap yang digunakan untuk pengujian keawetan contoh uji pada penelitian ini adalah rayap kayu kering (Cryptotermes cynocephalus Light.) Hasil penelitian menunjukkan kisaran hasil rerata nilai pada parameter absorbsi sebesar 33,09 – 70,77 kg/m3 , nilai retensi sebesar 3,81 – 10,77 kg/m3 , kedalaman penetrasi 2,34 – 3,86 mm, mortalitas rayap sebesar 46,33 – 53 % selama 2 minggu dan 82,67 – 94,33 % selama 4 minggu pengumpanan, pengurangan berat sampel sebesar 0,56 – 0,57 gram, serta derajat kerusakan sebesar 30,34 – 31,27 %. Hasil analisis sidik ragam menunjukkan bahwa terdapat interaksi antara faktor jenis bahan pengawet dan lama perendaman yang berpengaruh nyata terhadap mortalitas rayap. Faktor jenis bahan pengawet berbeda sangat nyata terhadap absorbsi dan penetrasi. Faktor lama perendaman berbeda sangat nyata terhadap absorbsi, retensi, penetrasi. Pemberian bahan pengawet mampu mengurangi kehilangan berat sampai sekitar 70 % serta memberi persentase kematian rayap yang lebih tinggi (87-92 %) dibandingkan gubal tanpa perlakuan.

Katakunci: Tectona grandis L.f., gubal, pengawetan kayu, boraks, rendaman dingin, Cryptotermes cynocephalus Light

Preservation of Teak Sapwood by Cold Soaking Using Boron Against Drywood Termite (Cryptotermes cynocephalus Light.) Attacks.

Abstract

The utilization of younger teakwood has a disadvantage, which is the sapwood is more susceptible to dry wood termites as it has less natural durability. Boric acid and borax are inexpensive preservatives, which contain boron as the active material. Those preservatives are also easy to be obtained as well as do not produce smells and the wood discoloration. The experiment materials were the sapwood parts from teak boards obtained from the felled trees in the community forest of Kali Bawang, Kulon Progo. A complete randomized block design was arranged in a factorial with two factors, which were the type of preservatives (boric acid and borax in 5% concentration) and duration of cold soaking (12, 24, 36, and 48 hours). To examine the durability of sample, dry wood termites (Cryptotermes cynocephalus Light) were used. The results showed that the average values of absorption, retention, and depth of penetration were 33.09 to 70.77 kg/m3, 3.81 to 10.77 kg/m3, and 2.34 to 3.86 mm, respectively. The average values of termite mortality during 2 weeks and 4 weeks were 46.33 to 53 %, 82.67 to 94.33 %. Weight reduction and degree of the damage were, 560 to 570 mg, and 30.34 to 31.27 %, respectively. By analysis of variance, there was an interaction between the type of preservatives and the duration of cold soaking factors, which affected significantly the termite mortality. Type of preservative affected significantly the absorption and penetration. Further, the duration of cold soaking affected significantly the level of absorption, retention and penetration. The application of preservatives could reduce the mass loss of specimens until 70 % as well as to give higher levels of mortality rate (87-92 %) compared to that of untreated one.