Survival, early growth and chemical characteristics of Paulownia trees for potential biomass production in a cool temperate climate.

Abstract

The results of two experiments to investigate the survival, early growth and chemical characteristics of six Spanish and three Moroccan genotypes of Paulownia, grown from container produced and bare root plants, respectively, are described. Both trials were planted in Northern Ireland (NI) and after three growing seasons the overall mean survival and height of the Spanish and Moroccan genotypes were 70.8% and 32.2% and 1.1 m and 2.2 m, respectively. Chemical characteristics, except for nitrogen and ash content, were similar to those reported for other biomass crops such as willow and miscanthus (Miscanthus × giganteus). Genotypes that performed well were PWST-33 (P. fortunei) from Spain and P. fortunei from Morocco. Biomass yields varied significantly and were considerably lower than those reported for other fast growing species grown as energy crops. The results suggest that the potential of Paulownia as an energy crop in NI is limited due to its low performance in biomass production. The main constraints to further planting of Paulownia in this region are the edaphic and climatic conditions that pertain, which appear not to be conducive to growth of this tree species.