POTENSI BIOMASSA DAN KARBON ORGAN AKAR TANAMAN MELINJO (Gnetum gnemon) PADA SISTEM AGROFORESTRI DI HUTAN RAKYAT DESA NGLANGGERAN, KABUPATEN GUNUNGKIDUL, DIY

YENI FATMADEWI, Dr. Ir. Ris Hadi Purwanto, M.Agr.Sc.

2015 | Skripsi | S1 KEHUTANAN

Pemanfaatan lahan dengan pengelolaan hutan rakyat sistem agroforestri memiliki peranan penting dalam menyediakan kebutuhan baik kayu maupun non kayu. Pengelolaan hutan rakyat sistem agroforestri ikut berkontribusi dalam pengurangan emisi gas karbon dioksida (CO2) yang merupakan salah satu penyebab perubahan iklim. Desa Nglanggeran merupakan kawasan yang mengembangkan hutan rakyat dengan berbagai jenis tanaman penyusun agroforestri antara lain tanaman melinjo (Gnetum gnemon) yang merupakan jenis tanaman multiguna (Multi Purpose Tree Species). Penelitian ini dilakukan untuk mengetahui potensi biomassa dan karbon serta serapan gas CO2 organ akar tanaman melinjo pada sistem agroforestri di hutan rakyat Desa Nglanggeran, Kabupaten Gunungkidul. Penelitian ini dibagi dalam 3 tahap yaitu pengukuran kandungan biomassa dan karbon organ akar tanaman melinjo, penyusunan persamaan allometrik menggunakan software statistik dan penaksiran potensi biomassa, karbon, dan serapan gas CO2 pada sistem agroforestri hutan rakyat Desa Nglanggeran. Pengukuran kandungan biomassa dan karbon organ akar tanaman melinjo menggunakan metode destructive sampling dengan pemanenan 18 pohon sampel dari berbagai ukuran diameter setinggi dada (dbh). Untuk mengetahui potensi biomassa, karbon, dan serapan gas CO2 dilakukan inventarisasi dengan metode stratified random sampling berdasarkan luas kepemilikan lahan terhadap 30 responden pemilik hutan rakyat. Hasil penelitian menunjukkan kadar karbon organ akar adalah 36,68% dari biomassa. Rerata kandungan biomassa organ akar yaitu 13,06 plus minus 5,929 kg/pohon sedangkan kandungan karbon yaitu 4,59 plus minus 2,146 kg/pohon. Persamaan allometrik hubungan diameter dengan biomassa adalah B = 0,021 Dbh pangkat 2,479 (R2 = 95,1%) sedangkan persamaan allometrik hubungan diameter dengan karbon adalah C = 0,009 Dbh pangkat 2,419 (R2 = 95,7%). Berdasarkan hasil inventarisasi diketahui rerata potensi biomassa adalah 1,046 plus minus 0,6156 ton/ha, rerata potensi karbon adalah 0,369 plus minus 0,2192 ton/ha, dan serapan gas CO2 sebesar 1,354 plus minus 0,8045 ton/ha.

Agroforestry system in community forest is important. Because it provide the timber and non timber products for people. It also has an contribution to reduce carbon dioxide (CO2) in the air, which is one of the causes of climate change. Melinjo (Gnetum gnemon) is one of the species that was developed in Nglanggeran Village with agroforestry system. Its also classified as Multi Purpose Tree Species (MPTS). The purpose of this research is to calculate the potency of biomass and carbon also calculate the absorption of CO2 gas of roots organ of melinjo in agroforestry system in Nglanggeran Village, Gunungkidul District. This research is consist of three steps: measuring biomass and carbon content of roots organ of melinjo, arrange allometric equation by using statistic software, and estimating potency of biomass, carbon, and absorption of CO2 gas in the agroforestry system, specifically in community forest of Nglanggeran Village. Destruction sampling method was used to measure biomass and carbon content of roots organ of melinjo. 18 trees with various diameter was used as samples. Inventory upon 30 respondents who own community forest in stratified random sampling based on the ownership of spacious land was conducted to determine the potency of biomass, carbon, and CO2 absorption. The result showed that carbon content of root organ was 36,68% of biomass. The average of biomass content of the roots organ was 13,06 plus minus 5,929 kg/tree and the average of carbon content was 4,59 plus minus 2,146 kg/tree. Allometric equation to estimate the biomass content of roots organ was B = 0,021 Dbh pangkat 2,479 (R2=95,1%) and to estimate the carbon content was C = 0,009 Dbh pangkat 2,419 (R2=95,7%). Based on the results of the inventory, the potency of biomass was 1,046 plus minus 0,6156 tons/ha, and the average carbon potency was 0,369 plus minus 0,2192 tons/ha, and the absorption of CO2 was 1,354 plus minus 0,8045 tons/ha.

Kata Kunci : Agroforestri, biomassa, karbon, CO2, allometrik, Gnetum gnemon