This report provides a detailed review of the literature on Paulownia research across the world. The main objective of this report was to assess the potential of Paulownia as a novel biomass crop for Northern Ireland, based on previous work in this area. Paulownia trees originate from China and are also grown throughout Asia, USA, Australia and Europe. Although a number of Paulownia species exist, only the ornamental species Paulownia tomentosa is currently grown in the UK. With optimal conditions in terms of light and moisture, Paulownia is reported to be one of the fastest growing trees in the world. The trees can be damaged by frost and require a sheltered place for growth.
Paulownia timber has many uses, including timber for construction, doors, furniture, kitchens etc. The deep rooting system of Paulownia in combination with the rapid rate of growth enables it to take up more nutrients than other species and may therefore offer potential for bioremediation purposes. Paulownia leaves can be used for animal feed and honey is made from the bright colourful flowers in China.
Intercropping with wheat is common practice in China, where it is important to utilise the ground for food production in addition to lumber purposes. There is little competition for nutrients between Paulownia and wheat in an intercropping system, whereas the converse applies to Paulownia-maize intercropping. Recent studies have acknowledged the possibility of Paulownia-switch grass intercropping, both being renewable energy resources.
Because of the high cellulose content of Paulownia, cellulosic ethanol can be produced as a renewable energy fuel. Cellulosic ethanol is reported to have much reduced greenhouse gas emissions when compared to ethanol produced via a sugar/starch-based fermentation.
Interest in Paulownia is gaining momentum around the world, due to its fast growing nature, the ability to take up nutrients and the potential for intercropping. Along with this, Paulownia may offer the possibility of producing home-grown timber, reducing the requirement for importation of timber into the UK, which is common practice. Considering that the majority of woody biomass in Northern Ireland comes from the growing of willow, Paulownia may also offer potential as a novel source of biomass in Northern Ireland. The fast-drying nature of the wood by natural methods (air drying) is interesting, considering the considerable energy requirements for willow drying. There are currently no Paulownia trees growing in Northern Ireland and they may offer potential for biomass and bioremediation purposes. It may also be worthwhile examining the potential of the leaves for fodder purposes.