This data release includes metadata and tabular data that document estimates of litterfall, koa moth (Scotorythra paludicola) caterpillar frass production, soil nutrients, and foliar nutrients during 2013-2014 at Hakalau Forest National Wildlife Refuge. During this time, there was a massive defoliation event of Acacia koa (koa) trees by the koa moth. We monitored these metrics in 4 sites that varied in forest structure and composition at Hakalau. We used resin bags under koa canopy where frass was directly falling as compared to open grass sites where no frass was falling to monitor soil inorganic nitrogen and phosphorus over time. By comparing soil with frass inputs to frass inputs over time we could watch for differential spikes in soil nutrients due to the outbreak event.