Increment and biomass in hybrid poplar and some practical implications

Growth data were collected from 41 stands of poplar (Populus sp.) growing on former farmland in Sweden, situated between latitudes 55 and 63° N. The mean age of the poplar was 20 years (range 4-73), the mean stand density 1327 stems ha⁻¹ (range 155-4690), and the mean diameter at breast height (over bark) 210 mm (range 49-447 mm). Soil types in the poplar stands were mainly clay (25 stands), other sediments (six stands) and sandy-silty till (10 stands).The mean total standing dry weight above stump level (≈200 mm) for poplar was 141.9 ± 13.9 ton ha⁻¹ with a range of 19-438 ton ha⁻¹. In addition to estimating conventional dry weights of trees and tree components, SLA, PLA and LAI, among other measures, were estimated and were in agreement with published figures.The results indicate that poplar stands could produce 70-105 ton ha⁻¹ after 10-15 years growth mainly used for biofuel. Otherwise, the stands could be thinned for pulpwood and timber production with a rotation period of 25-30 years and the thinnings used for biofuel.