Climate change "drives" palm trees to the north

First palm forest in the Alps

Palm © IMSI MasterClips
Read out

Global warming is making palm trees thrive in areas where it was previously not possible due to cold winter conditions. This also applies to parts of Central Europe, where recently the world's northernmost free-growing palm population can be found. The palms can also be planted further and further north in gardens. This has now found an international research group in a new study.

As part of the European research project ALARM (Assessing LArge scale Risks for biodiversity with tested

Methods), among other things, investigates the effects of ongoing global warming on the composition and distribution of vegetation. As a research group around the plant ecologist Gian-Reto Walther from the University of Bayreuth has now discovered, is among the species favored by climate change and the palm species Trachycarpus fortunei.

While this Southeast-Asian species was able to survive for a long time in gardens and parks under the care of humans, it failed to successfully settle outside the gardens in competition with indigenous species. Only the milder winters of the recent past allowed this palm species to grow wild out of the gardens.

A forest of palm trees?

Feral palm population in a forest at the Alpensüdfuss. © G.-R. Walther

For a few decades, Trachycarpus fortunei has been able to gain a foothold in the forests, grow up and rejuvenate outside the gardens. This has been proven by the scientists at various points on the southern tip of the Alps in the border region of Switzerland and northern Italy. There is now the new world's northernmost growing in the forest palm population. display

But not only on the southern side of the Alps, also north of the Alps, is the climate change noticeable. The palm trees planted in the gardens need less and less protection in winter, or survive the winter in West Germany unprotected outdoors, the researchers said. Even there, older specimens already show flowering and fruiting habitats, and seedlings are found in some places under mature palms.

Climate change ensures good growth conditions

This early stage of rejuvenation in gardens was also observed south of the Alps at the beginning of the 20th century, but was not enough to successfully bring it into the wilderness. Only with the further warming over the last century did the climatic conditions for the survival of the wild palm trees in the forests become noticeably more favorable. However, with the climate change forecast for this century, it is also to be expected north of the Alps, according to the scientists, that, as in the south, the conditions for palm trees are becoming increasingly favorable become.

The Trachycarpus palm is planted in many areas of the world in the border area of ​​global palm distribution due to its winter custody. Thus, across continents, the current and expected climate change can be observed in one and the same plant species: the palm tree thus becomes the indicator and witness to global warming.

(idw - University of Bayreuth, 08.06.2007 - DLO)