Ornamental, crop, or invasive? The history of the Empress tree (Paulownia) in the USA

Abstract

The Paulownia tree first arrived in the USA in the early nineteenth century and quickly transitioned from an exotic oddity to a beloved ornamental by some and a reviled invasive species by others. Many gardeners and horticulturalists praised the tree for its rapid growth and beautiful lavender blossoms. Critics thought the non-native tree a threat to native flora and sought its eradication. One species, Paulowniatomentosa, is invasive and has been especially vilified by organizations ranging from the National Park Service and National Forests Service to the US Department of Agriculture. Another species, Paulowniaelongata, started to gain attention as a viable domestic tree crop in the 1980s. Demand derived primarily from Asian countries, especially Japan where the tree had been traditionally used for dowry chests, furniture, and musical instruments. Due to over harvesting, Japan had suffered a severe shortage to the extent that Paulownia made up a large chunk of the country's wood imports. P. elongata and various hybrids are currently grown by Americans ranging from diversified farmers to businessmen and even former president Jimmy Carter. Paulownia growers believe that the tree's value expands beyond furniture and other carvings to environmental possibilities such as biofuels, biomass, electricity, and even air purification. Deemed a pest by some and a profitable commodity by others, the Paulownia has become a permanent part of the American landscape but measures must be taken to contain P.tomentosa and keep P.elongata from becoming invasive.