Site preparation affects survival, growth of koa on degraded montane forest land.
Banana poka vines (Passiflora mollissima) and kikuyu grass (Pennisetum clandestinum) can limit koa (Acacia koa) reforestation in Hawaii. Performance of planted koa seedlings was studied in relation to type of site preparation: broadcast spraying of Roundup [glyphosate] at 2.02, 4.05 and 6.07 kg/ha; and hand scalping vegetation at each planting spot. One yr after planting, survival and growth of koa seedlings were significantly greater in plots sprayed with the largest dose of Roundup than in control plots. Ten-yr survival and height were significantly greater for the heavy-dose treatment than for the scalp treatment, but none of the trees in the control treatment were alive.