KARAKTERISTIK PENGERINGAN SUHU TINGGI PADA KAYU JATI DARI HUTAN RAKYAT KULON PROGO DENGAN VARIASI PERLAKUAN KEDALAMAN DAN KERAPATAN INCISING

HARITS KURNIA PUTRI, Tomy Listyanto, S.Hut., M.Env.Sc., Ph.D

2017 | Skripsi | S1 KEHUTANAN

Pengeringan kayu merupakan salah satu proses penting yang dilakukan untuk meningkatkan kualitas kayu. Namun, pengeringan membutuhkan waktu yang lama dan biaya yang tidak sedikit. Salah satu cara untuk mempercepat waktu pengeringan adalah dengan incising dan pengeringan suhu tinggi. Penelitian ini bertujuan untuk mengetahui pengaruh interaksi kedalaman dan kerapatan incising pada laju pengeringan dan cacat pengeringan serta pada sifat mekanika kayu jati dari hutan rakyat Kulon Progo yang telah dikeringkan. Pohon jati rakyat dari Kulon Progo berdiameter 29-30 cm dan berumur 15 tahun digunakan pada penelitian ini. Rancangan acak lengkap dengan 2 faktor yaitu kedalaman dan kerapatan incising. Kedalaman incising dengan 3 variasi yaitu ½ ¾ dan tembus tebal. Dua jenis kerapatan meliputi 2500 dan 5000 lubang/m kuadrat. Lubang incising berdiameter 3 mm. Sampel pengeringan dikeringkan hingga kadar air 12%. Parameter yang diamati meliputi laju pengeringan, retak permukaan, retak dalam, dan cacat perubahan bentuk. Uji keteguhan lengkung statik dilakukan berdasarkan standar British 373. Analisis varian pada taraf uji 5% dilakukan untuk menentukan pengaruh dari interaksi kedalaman dan kerapatan incising terhadap laju pengeringan, cacat dan sifat mekanika kayu jati yang dikeringkan. Untuk mengetahui perbedaan tersebut dilakukan uji lanjut Honestly Significant Difference Tukey. Hasil penelitian menunjukkan bahwa variasi kerapatan dan kedalaman incising berpengaruh nyata terhadap laju pengeringan. Laju pengeringan terbesar terdapat pada kedalaman tembus tebal kerapatan incising 5000 lubang/m kuadrat sebesar 19,724% per hari. Faktor kedalaman incising berpengaruh nyata terhadap cacat twisiting. Interaksi faktor kedalaman dan kerapatan incising menurunkan Modulus Patah (MoR) dan Modulus Elastisitas (MoE) kurang dari 9%.

Wood drying is one of the best methods to increase wood's quality. However, wood drying needs long time and high cost. Incising and high temperature drying methods are alternatives to increase drying rate. This research aimed to determine the effect of interaction between depth and density of incising on drying rate, defects, and mechanical properties of dried teak wood grown in community forest in Kulon Progo. Teak trees with diameter of 29-30 cm and 15 years old from community forest in Kulon Progo were used in this research. The samples were completely randomized design with two factors, depth and density of incising. Three variations of incising depth are 1/2 thickness, 3/4 thickness, and full depth. Two types of incising densities are 2500 and 5000 holes / m square. The diameter of incising hole was 3 mm. The drying samples were dried until reaching final moisture content of 12%. Drying rate, surface checks, honeycomb, and warping were observed to measure the drying characteristic. Static bending test was also conducted accordingly to the British Standard 373. Variance analysis in 5% of significant level were performed to examine effect of interaction between depth and density of incising on drying rate, defects, and mechanical properties of dried teak wood. The difference was determined by Honestly Significant Difference Tukey test. The result shows that the variations of depth and density incising influence significantly on the drying rate. The highest drying rate occurred in the incising density of 5000 holes/m square which was 19,724% per day. Incising depth influences significantly on twisting. Interaction between incising depth and density decreased Modulus of Rupture and Modulus of Elasticity less than 9%.

Kata Kunci : pengeringan, suhu tinggi, jati, kedalaman, kerapatan, incising;density, depth, drying, high temperature, incising, teak wood