What do intensive agricultural expansion, urbanization, sandalwood harvesting, and unmanaged grazing have in common? They all result in deforestation and depleted soil, both globally and across the Hawaiian Islands.
A desirable, fast-growing, nitrogen-fixing tree such as Gliricidia sepium could increase the organic carbon in soils, provide shade, and prepare the land for subsequent plantings. But what’s the best way to plant it out?
This is where M.S. candidate Travis Usinger’s research comes in. Travis, in the Dept. of Natural Resources & Environmental Management, will defend his thesis, “An Evaluation of Moisture Management Approaches for Vegetative Propagation of Gliricidia sepium in Arid Landscapes” via Zoom on August 5 at 2 p.m. to address just that question.
A common name for Gliricidia sepium is “quick stick” because of the tree’s ability to quickly and easily be propagated by vegetative stakes. However, in conditions with lower rainfall these stakes have a low rate of survival compared to seedlings. Travis examined factors that could help to increase survival in vegetative cuttings, including pretreatment of stakes, moisture management through irrigation and hydrogel amendment, and diameter size, to determine their relationship to survival and growth of gliricidia at the Plant Materials Center on Moloka‘i.
Travis’s committee is Linda Cox, Travis Idol, and J.B. Friday.