Reasearches on Short-Rotation-Forestry with poplar in the South-Eastern part of the Po Valley (Italy)

Abstract

Eight poplar clones (83.148.041; 85.036; 85.037; 84.078; I 214; AF2; AF6 and Pegaso) are under comparison in Short-Rotation-Forestry (SRF) plots established in the early spring 2004 in silty-clay soils of the Po Valley near Ferrara (Emilia-Romagna region). Clones 83.148.041; 85.036; 85.037 and 84.078 were planted in single rows at a density of 8900 trees ha-1, while clones AF6 and Pegaso were planted in twin rows at density of 11300 trees ha-1. Clones I 214 and AF2 were planted at both the above mentioned densities and planting schemes. Plots were arranged in a randomised block design with three replications. At the end of the first growing season all the stems were cut 10 cm above the collar (back cutting) in order to enhance sprout number and vigour. At the and of the first and second growing season the following data were collected: plant survival; stem diameter at the base and 1,30 m height; stem height; nr. of stems per stump; percentage of stems with silleptic branches. Stem and branch samples were collected and weighted in the field and dry w./fresh w. ratio was determined in laboratory. These data were used for the calculation of the annual clone productivity expressed in t d.m. ha-1. At the end of the second year of the trials the eight clones did not show significant differences at the statistical analysis in terms of stem dimensions and productivity, even if the higher annual biomass production was observed with 83.148.041 (8.89 t d.m. ha-1) for the single-row and with I 214 (5.40 t d.m. ha-1) for the twin-row plots. Pegaso and 84.078 showed the lowest results in terms of both survival and productivity. However, an increase in clone differentiation and productivity is expected in the next years of the research. On the whole, clone performance was better in single-row than in twin-row plots. These first results are compared with those of other SRF experimental plantations in the Po Valley.