Biomass production and energy potential of some eastern cottonwood (populus deltoides bartr. ex marsh.) clones in relation to planting spacing

Abstract

The possibility of biomass production was studied in an experimental trial stand with four clones of Eastern cottonwood Populus deltoides Bartr. ex Marsh. cl.457, cl.450, cl.618 and cl. 55/65 and three stand densities a) 1.2 × 1.0 m (8330 plants•ha-1), b) 1.2 × 0.75 m (11110 plants•ha-1) and c) 1.2 × 0.5 m (16600 plants•ha -1). Field trials were conducted on sandy-loamy form of fl uvisol. Total determined volume of trunk, bark, and branches in the fi rst two-year cycle for the used Eastern cottonwood ranged from 27.391 m3• ha-1 in clone 450 at planting distance of 1.2 × 1.0 m, subtreatment (a) to 42.006 m3•ha-1 in clone 618, subtreatment (c) at planting distance of 1.2 × 0.5 m. Aft er renovation of stand using the regeneration force of shoots from the tree stumps the produced wood mass in the second two-year cycle ranged from 54.664 m3• ha-1 in clone 55/65, subtreatment (a) to 79.235 m3• ha-1 in clone 450, subtreatment (b). In additon to clone selection a signifi cant infl uence on biomass yeald was also exerted by stand density (number of plants•ha-1). Th e largest amount of heat energy would be obtained in subtreatment (c) at density of 1.20 × 0.5 m by combustion of biomass of above ground part of clone 55/65: 364.02 GJ•ha-1 in the fi rst cycle, and 659.83 GJ•ha-1 in the second, or a total of 1023.85 GJ•ha-1.