Paulownia ( ) is a genus of seven to 17 species of hardwood trees (depending on taxonomic authority) in the family Paulowniaceae, the order Lamiales. The genus and family are native to east Asia and are widespread across China. The genus, originally Pavlovnia but now usually spelled Paulownia, was named in honour of Anna Pavlovna, queen consort of The Netherlands (1795–1865), daughter of Tsar Paul I of Russia. It is also called "princess tree" for the same reason.

It was originally sought after as an exotic ornamental tree in Europe and Asia, and later introduced to North America in 1844. Its fruits (botanically capsules) were also used as packaging material for goods shipped from East Asia to North America, leading to Paulownia groves where they were dumped near major ports. The tree has not persisted prominently in US gardens, in part due to its overwintering brown fruits that some consider ugly. In some areas it has escaped cultivation and is found in disturbed plots. Some US authorities consider the genus an invasive species, but in Europe, where it is also grown in gardens, it is not regarded as invasive.

Paulownia trees produce as many as 20 million tiny seeds per year. However, the seeds are very susceptible to soil biota and only colonize well on sterile soils (such as after a high temperature wildfire). Well-drained soil is also essential. Successful plantations usually purchase plants that have been professionally propagated from root cuttings or seedlings. Although seeds, seedlings, and roots of even mature trees are susceptible to rot, the wood is not and is used for boat building and surfboards.

Dimensionally stable and given its straight grain and light weight, Paulownia timber is extremely easy to work with and is reported to be resistant to decay, with good weathering characteristics.

Trees can grow to maturity in under 10 years and produce strong, lightweight timber, good as firewood, and with an even higher strength to weight ratio than balsa wood. Its density is low at around , although significantly higher than balsa's very low .

Morphology

thumb|Paulownia tomentosa

Paulownia is a genus of angiosperm trees, and one of the fastest-growing trees in the world. Paulownia tomentosa can grow over tall and has large heart shaped leaves ranging from wide and long with a -long petiole. The leaves grow in opposite decussate pairs, and as the name tomentosa suggests, are covered in hairs. The leaf margin can be toothed or entire and sometimes may be slightly lobed. They can be distinguished from common look-alike genera, such as Catalpa and Cercis, by secondary and tertiary venation.

Paulownia macrofossils have been recovered from the late Zanclean stage of the Pliocene sites in Pocapaglia, Italy and Paulownia caucasica macrofossils have been recovered from strata of the Serravallian stage of the Miocene in Georgia in the Caucasus region. It is believed that the climate then would have been suitable for the genus across the whole northern hemisphere.

Uses

In China, Paulownia () is popular for roadside planting and as an ornamental tree. Paulownia needs much light and does not like high water tables.

As a forestry crop, Paulownia are exacting in their requirements, performing well only in very well draining soil, with summer rainfall or availability of irrigation water. Paulownia is extremely fast growing, increasing in height by up to in one year when young. Some species of plantation Paulownia can be harvested for sawn timber in as little as five years. Once the trees are harvested, they regenerate from their existing root systems, earning them the name of the "Phoenix tree" (that name is alternatively attributed to the belief that it is the only tree within which the phoenix will roost.)

Paulownia is also used in Chinese agroforestry systems because it grows quickly, its wood is light but strong, its flowers are rich in nectar, its leaves make good fodder for farm animals, it is deep-rooting, and it is late-leafing, and its canopy is sparse enough to allow crops below it get enough light to grow while being sheltered from the wind.

thumb|This Paulownia flower pattern (go-shichi-no-kiri) is the symbol of the Office of the Prime Minister of Japan. It also decorates the [[Order of the Rising Sun and the Order of the Paulownia Flowers and is a crest of the Eihei-ji Zen temple.]]

Paulownia is known in Japanese as , specifically referring to P. tomentosa; it is also known as the "princess tree". Paulownia is used in the Government crest of Japan, which serves as the symbol of the prime minister, Cabinet and the Government of Japan (whereas the chrysanthemum is the imperial crest of Japan, used by the Emperor and the Imperial Family). It is one of the suits in the card game hanafuda, associated with the month of December in Japan, or November in Korea.

Japan: An Illustrated Encyclopedia states:

<blockquote>Paulownia wood is very light, fine-grained, and warp-resistant. It is the fastest-growing hardwood. It is used for chests, boxes, and clogs (geta). The wood is burned to make charcoal for sketching and powder for fireworks, the bark is made into a dye. The silvery-grey wood is sliced into veneers for special visiting cards.</blockquote>Paulownia boxes called tomobako (ともばこ) protect ceramic works and other fragile items during shipment and storage. The lid of the box usually tied down with a flat ribbon called a sanada-himo (真田紐). Japanese wardrobes called tansu (箪笥) as well as much Korean lacquerware is also made from the wood.thumb|A [[Japanese , 95–97% gold, "Paulownia" mark, emblem, 373.11 grams, Japan]]

It is important in China, Korea, and Japan for making the soundboards of stringed musical instruments such as the guqin, guzheng, pipa, koto, and gayageum. and for surfboard cores. It is typically used in guitars as the core body, then laminated under a more durable wood.

Species

left|thumb|Paulownia fortunei flowers and bark

Tested and confirmed species:

Potential variety, hybrid, and synonym species:

References

  • Paulownia forestry information
  • Paulownia Research Center in China (Shaanxi)
  • Flora of China - Paulownia
  • Paulownia trees.org
  • silvatree.com: Paulownia forestry
  • fadr.msu.ru: "Paulownia, the Tree of Choice in China"