One poplar (2293-19 Populus tricocarpa X P. nigra) and three willow varieties (9982-41 Salix purpurea; SV1 S. dasyclados; SX67 S. miyabeana) were arranged in a randomized complete block design with three replications, to test varietal influence on aspects of nutrient cycling. In an ancillary study, SV1 and SX67 were fertilized to test differences in nutrient dynamics as influenced by fertilizer application. In both studies, nutrient inputs from atmospheric deposition, nutrient transfers from leaf litterfall and decomposition, and nutrient outputs from woody biomass harvest, as influenced by species and fertilizer applications were investigated. Poplar system nutrient depletions after a three-year harvest cycle were observed. Total mean nutrient accumulations in the three willow varieties was +101.87, +18.72, +45.60, +449.95 and +37.37 kg·ha-1 for N, P, K, Ca, and Mg, respectively. External fertilization did not enhance yield or site productivity; therefore, it is recommended to limit fertilization in these systems to maintain carbon neutrality.