Comparison between two and five years rotation models in poplar, willow and black locust Short Rotation Coppices (SRC) in North West Italy

Currently, SRC plantations should produce multiple assortments, both for industrial and energetic uses, for being economically profitable. SRC trials comparing two different cultivation models (very high density model -– vHDM, 8,333 trees ha -1 with 2 years rotation; high density model -– HDM, 1,667 trees ha -1 with 5 years rotation) were established in 2005 in two sites (Casale Monferrato and Cavallermaggiore), on agricultural land with alluvial soils in the Western Po Valley (Italy). Both models were applied to poplar (clone 83.141.020), willow (clone S76-008) and black locust (provenance Energy). After 6 years from planting, the two treatments did not show significant differences in terms of cumulative biomass yield, with poplar being the most productive species at Casale Monferrato (64.65 and 63.76 Mg ha -1 with HDM and vHDM, respectively). Poplar production potential was confirmed at Cavallermaggiore (105.83 and 57.22 Mg ha -1 , respectively). Black locust showed the lower yield at both sites. In HDM poplar exhibited the highest stem DBH, at both sites, reaching mean values of 15.0 and 17.8 cm at Casale Monferrato and Cavallermaggiore, respectively. In HDM, poplar was the only species capable to reach stem dimensions compatible with industrial destinations at the end of the first 5- years rotation.