Mass propagation of Eucalyptus species for essential oils: sustainable techniques for Indonesian forestry

This research aimed to arrange the most suitable propagation techniques for the five eucalypts producing essential oils, E. tereticornis, E. camaldulensis, E. urophylla, E. deglupta, and E. citriodora, in KHDTK Wanagama, Yogyakarta Province. The sprouting formation was stimulated by girdling techniques, followed by shoot harvesting at 21 days after the first emergence. A completely randomized design was applied in a factorial experiment with two levels of hormones ((1) 100 g/liter onion extract and (2) 100 mg/L IBA, all soaked for 20 minutes) and two types of rooting media ((1) sand: cocopeat (2:1), and (2) sand:topsoil: cattle dung (2:2:1)). Results showed that E. urophylla, E. camaldulensis, and E. teretricornis produced the highest girdling survival (100%), followed by E. deglupta (60%). The girdled E. citriodora failed to produce sproutings. A combined treatment of 100 gr/liter onion extract, with sand, topsoil and cattle dung (2:2:1) media, gained the highest cutting ability at all species and parameters observed. The eight-week-old E. deglupta cuttings treated with 100 gr/liter onion extract and planted in the sand, topsoil, and cattle dung (2:2:1) media gained the highest survival, root formation, and leaves production, followed by the E. urophylla cuttings. The E. teretricornis cuttings failed to survive in IBA hormones, but the application of onion extract helped to improve the survival. Unfortunately, no cuttings of E. camaldulensis survived at any hormone and media treatments. This study may contribute to arranging better strategies for the mass production of selected eucalypts. © The Authors, published by EDP Sciences.