USE OF ROOT-INGROWTH CORES TO ASSESS NUTRIENT LIMITATIONS IN FOREST ECOSYSTEMS

We tested the suitability of using root-ingrowth cores to identify nut rient limitations in a Metrosideros-dominated forest in Hawaii that pr eviously was demonstrated to be nitrogen limited. Plastic mesh cylinde rs filled with a calcined-clay growing medium were treated with nitrog en, phosphorus, calcium and potassium, or distilled water, and were in serted into the surface soil of the forest. After 6 months in situ, si gnificantly more roots grew into the cores dosed with nitrogen. Fertil ization trials provide the best means of identifying nutrient limitati ons to forest growth, but our results indicate that root-ingrowth core s can provide a reliable, alternative method of assessing nutrient lim itations in forest ecosystems.