Strategies for the processing of tree tops from hybrid poplar plantations

Industrial poplar plantations represent a strategic source of wood products for many countries. Harvested after 10 to 30 years, they yield about 200 t ha-1 of timber and 100 t ha-1 industrial wood. The latter is obtained from poplar tops, which can be converted into chips, or a mix of pulpwood and chips. The study compared four options to process poplar tops. Alternatives derived from the intersection of two product strategies (pulpwood and chips, or chips only) with two pulpwood processing methods (manual or mechanized). Both mechanization and simplification (only one product) succeeded in reducing production cost, but the former had a stronger effect. The tests demonstrated that all options were cost-effective and could return some profits. However, the exclusive production of chips offered lower profits, compared to an articulate product strategy aimed at maximising value recovery. In the case of Italian poplar plantations, the price difference between pulp and chips is generally larger than the cost reduction obtained with integral chipping. Similar conclusions were reached by other authors working with spruce and beech in Central Europe. Of course, this is only true for the current price levels of pulpwood and chips: results may change, if this price balance will be altered by the growing demand for biomass fuel.