Chinese Empress Tree

Ses abondantes fleurs lilas et son arôme parfumé en font un favori .....

Its abundant lilac flowers and fragrant aroma make it a favourite for gardeners and landscape designers. But the Chinese empress, or kiri, tree is beginning to ring alarm bells among scientists and environmental authorities in Latin America.

Colombia just declared this leafy tree (scientific name Paulownia tomentosa) as a species with a “high risk of invasion”. There are still relatively few planted in the country, mostly for timber, but the preventive move has concerned growers.

Long life

Despite its beauty and valuable wood, Colombian scientists fear the kiri could be an ecological time bomb. It grows at an impressive rate and produces thousands of seeds that are dispersed by the wind. Its branches can reproduce new trees and it sprouts easily after fire.

These advantages make it a “super species” that thrives in environments such as pastures and streams. Yet this is precisely what makes it a very difficult plant to control.

As a result, the Colombian Government’s National Committee of Invasive Alien Species concluded two months ago that it would be better to avoid its proliferation rather than regret it. The body is responsible for evaluating the risks of non-native species in Colombia, the second most biodiverse country in the world.

The Ministry of Environment is now in the process of adopting the committee’s recommendation. Three of its members – two government scientific institutes and the largest public university in the country – presented technical studies warning about this tree with hairy, heart-shaped leaves and oval capsules that shoot thousands of flying seeds.

Unlike in Brazil, Argentina and Paraguay, where it was introduced in the 1950s, there are still no reports of large wild populations of kiri crops in Colombia. The Colombian government, however, opted for caution. Twelve states in the US, where the kiri was introducedin the mid-nineteenth century, now consider it an invasive species.

“It is sad to detect the effects of invasive species when they have already occurred. The ideal is to think in a preventive way, to avoid them from happening,” says ecologist Carolina Castellanos, one of the scientists at the Alexander von Humboldt Biological Resources Research Institute (IAVH) who evaluated the risk of kiri.

After studying scientific information from other countries, the IAVH concluded that the tree, whose seeds are freely sold on the internet, represents a significant risk for the country.

Dairon Cárdenas, curator of the herbarium at the Amazon Institute for Scientific Research (SINCHI), said: “It is based on the precautionary principle. If the species has biological characteristics that make it an invasive one, such as the speed of its reproductive strategy, it is recommended to manage it more carefully.”

Last month, in a fit on excessive spring exuberance, I blogged about the redbud tree, one of the first trees to blossom as the weather warms. Spring has been a bit delayed here and tree enthusiasts have yet to spy the redbud’s lovely reddish-pink blooms. Nevertheless, I am going to continue the theme by writing about another tree which stands out on account of its beautiful pastel flowers–the empress tree (Paulownia tomentosa), a deciduous tree from western and central China. Also called the foxglove tree and the princess tree, the empress tree is covered with huge pale purple fountain-shaped blossoms in early spring. Growing faster than virtually any other deciduous tree, the paulownia readily proliferates throughout temperate climates. Its wood is easy to tool and carve while also durable and pretty.