18.8 C
New York
Saturday, May 28, 2022

South-north gradient in tree growth: climate change also endangers beeches in Central Europe – knowledge

- Advertisement -
- Advertisement -

Climate change is putting pressure on European beeches in much of Europe, particularly in the south of the continent. According to one study, the growth of these trees has reduced by as much as 20 percent since 1955. In the course of climate change, it could drop there by an additional 50 percent by 2090.

A European research group reports that decreased growth is a harbinger of increased tree mortality. She has more than 780,000 tree ring measurements in about 5,800 beeches (wild fagus) evaluated at 324 locations in Europe.

The team led by Edurne Martínez del Castillo from the University of Mainz entered the measurement results, as well as precipitation, maximum and minimum air temperatures, and other location factors into a computer model. The result, published in the journal Communications Biology, shows spatially and temporally resolved thickness growth rates for common beech.

[Wenn Sie aktuelle Nachrichten aus Berlin, Deutschland und der Welt live auf Ihr Handy haben wollen, empfehlen wir Ihnen unsere App, die Sie hier für Apple- und Android-Geräte herunterladen können]

Developments in an optimistic and pessimistic scenario

The researchers compared the growth rates of the periods from 1955 to 1985 and from 1986 to 2016. Consequently, the growth of beeches in Spain, Italy and the Balkans has been reduced by up to 20 percent. By contrast, growth in southern Sweden and Norway increased by as much as 20 percent.

In this northern range, it is mainly the long cold spells that limit tree growth. There, an increase in average temperatures can lead to higher growth rates.

The rings in the cross section of the tree trunk result from annual growth. Strong rings show years with favorable…Photo: Edurne Martinez del Castillo

Using the data, the scientists used a forecast model to calculate how development will continue through 2090 under changing climate conditions. To do this, they used two future scenarios that the Intergovernmental Panel on Climate Change (IPCC) also uses in its status reports: According to the optimistic scenario (SSP1-2.6), effective measures will be taken very soon to combat climate change, while in the pessimistic scenario (SSP5-8.5) hardly anything is done about it.

According to the model, even in the optimistic scenario, copper beech growth rates in southern Europe will decline by as much as 30 percent by 2050 compared to the period from 1986 to 2016. In contrast, the researchers predict a higher growth of up to 35 percent for southern Scandinavia and up to 25 percent for higher altitudes in Central Europe.

The forecast up to 2090 is similar: in the pessimistic scenario, beech growth could also decrease by 20 to 30 percent in Central Europe, and growth in southern Europe could even fall by more than 50 percent, especially in particularly dry regions.

“Tree of the Year” in trouble

“These clear growth trends indicate increased forest mortality, as growth decline has been reported to be a precursor to tree death,” the authors write. This would also affect Germany: while in the optimistic scenario, lower growth rates in some regions are largely offset by higher growth rates in other areas, the pessimistic scenario paints a bleak picture: by 2090, growth of beech would increase until it decreased to 30 percent. The smallest growth rates would only occur in some regions of the lower mountain range.

The common beech is considered less susceptible to climate change than other deciduous trees such as oak, maple, linden or ash. However, it has also suffered from drought and forest damage in recent years, Stefan Meier, president of the Tree of the Year Foundation, explained last fall. To draw attention to the danger of the common beech, the foundation chose the species as “Tree of the Year 2022”.

Source link

- Advertisement -

New Articles