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 litter traps to monitor koa litter fall over time and foliar %N to estimate N inputs from litter. We used caterpillar counts, koa canopy estimates, frass production rates, and frass %N to estimate N inputs from frass on the landscape. 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 N and P over time. Finally we collected foliage of various plant species over time, and tested for %N, under koa versus in the open to track how nutrients in frass fall may track into plants.