This data release includes data and metadata on litterfall rates, foliar nitrogen and carbon, grass biomass, soil nitrogen and carbon, and native outplant survival rates for an experiment that added large quantities of woody litter to a restoration forest in an attempt to lower soil nitrogen and exotic grass biomass. All sites were within Hakalau Forest National Wildlife Refuge on Hawaii Island. Broadly, this study looked at the ability to alter soil nitrogen cycling, exotic grass biomass and native outplant survival with large quantities of Metrosideros polymorpha litter in a forest dominated by Acacia koa.