The environmental impact of timber production from poplar plantation was evaluated by means of Life Cycle Assessment (LCA) using an attributional approach. A comparison was performed between a baseline scenario and an alternative one in which different harvesting operations were identified. An economic allocation was adopted to solve the multi-functionality of the studied process, by taking into account the price of the main product and of co-products. Sensitivity analysis was performed on alternative mass allocation and yield variations that derive from using high sustainability plants or from climate stress. A different characterization method was also analyzed. Among the different field operations, crop management involves a higher impact respect to field preparation-planting and harvesting-soil restoring. Emissions related to fertilizers' applications are the main responsible for acidification, eutrophications and particular matter formation. The results show that the modelling of the environmental impact of timber production is robust. The alternative scenario resulted better than baseline for all impact categories (impact reduction ranging from 0.1% to 12.4%), except for HT-noc (+12.2%) and POF (+20.6%), due to fuel and oil consumption in the chainsaw used for harvesting. In the next years, introducing high-sustainability clones (characterized by higher yield and higher resistance to pests and drought) could be an effective way for reducing the environmental impact of poplar roundwood production.