Evaluation of a Single-Pass, Cut and Chip Harvest System on Commercial-Scale, Short-Rotation Shrub Willow Biomass Crops

Harvesting is the single largest cost in the production of short-rotation woody crops (SRWC) like shrub willow, and previous systems tested in North America have not been effective for the size of material grown. The objective of this study was to evaluate the performance of a single-pass, cut and chip harvester in conjunction with two locally sourced chip collection systems on 54 ha of coppiced willow harvests in New York State. Harvesting and collection equipment was tracked for 153 loads over 10 days of harvesting using GPS data loggers. Effective material capacities (Cₘ) increased linearly with standing biomass up to 40 to 45 Mgwₑₜ ha⁻¹because ground speed was limited by ground conditions. This relationship changed dramatically with standing biomass in the 40–90 Mgwₑₜ ha⁻¹range, where Cₘplateaued between 70 and 90 Mgwₑₜ h⁻¹and was limited by crop conditions and harvester capacity. The relationship between standing biomass and the harvester’s Cₘwill probably change under different crop and ground conditions. The size of the harvester and the experience of the operator are other factors. This nonlinear relationship will impact cost and optimization modeling SRWC systems. Improperly sized headland and long haul distances impeded the performance of locally sourced collection systems resulting in a 33 % decrease in Cₘfrom the field to the headlands, and 66 % from the field to short-term storage as biomass moves through the system.