Climate change considerably threatens Europe's beech forests
Tree ring analyses reveal growth declines over recent decades

Date:
March 16, 2022
Source:
Johannes Gutenberg Universitaet Mainz
Summary:
Beech forests in Europe are severely threatened by climate change,
particularly in southern European countries, but also in central
Europe.

Models project severe beech growth declines over the next 70 years -
- ranging from 20 percent to perhaps more than 50 percent depending
on the climate change scenario and the region in question.



FULL STORY ========================================================================== Beech forests in Europe are severely threatened by climate change,
particularly in southern European countries, but also in central
Europe. Models project severe beech growth declines over the next
70 years -- ranging from 20 percent to perhaps more than 50 percent
depending on the climate change scenario and the region in question. "We
expect high productivity declines due to increased drought severity,
especially at the southern limits of the beech's distribution range," said
Dr. Edurne Martinez del Castillo from Johannes Gutenberg University Mainz (JGU). She warns that this will seriously affect both the environment
and forestry and urgently recommends that measures be taken to adapt
the forests. Furthermore, beech forests are crucial stores of carbon
dioxide. The models are based on tree ring analyses from all over
Europe using well-established climate scenarios. The study was funded
by the Alexander von Humboldt Foundation and has now been published in Communications Biology.


==========================================================================
Tree rings from 324 sites in Europe examined Beech is one of the
most important trees in the forests of Europe. Beech forests are both economically important and ecologically highly valuable.

Almost 100 beech forest regions in 18 European countries are listed as
UNESCO World Heritage Sites. However, climate change could place severe pressure on stocks in the future, both in geographical and ecological
terms. Evidence of this has already been published in regional studies,
but to date no comprehensive analysis has been conducted.

Edurne Martinez del Castillo, a member of Professor Jan Esper's
Climatology Group at Mainz University, has now investigated this
development for the species Fagus sylvatica, together with cooperation
partners from 32 scientific institutions. They performed over 780,000
tree ring measurements on 5,800 trees at 324 sites across Europe,
from the north of Scotland to mainland Greece. This data allowed them
to analyze the growth rates of the trees over the past six decades,
enabling them to forecast likely trends in the future.

Tree growth has declined in virtually all regions The results reveal
marked geographical differences between the two study periods of 1955
to 1985 and 1986 to 2016. For example, the model tree growth rate over
the past six decades was two to three times higher in low-lying areas of northwestern and central Europe -- such as coastal regions in Belgium,
the Netherlands, Denmark, and the British Isles -- than towards the
southern distribution limits. Comparing the two 31-year periods revealed a remarkable decline in tree growth in almost all distribution regions. The models reveal that the strongest contrast is between northern Europe with Sweden and Norway, where growth has risen by 20 percent, and southern
Europe, where growth has declined by as much as 20 percent.

Researchers expect drastic losses in southern Europe during the 21st
century Based on two widely accepted climate research scenarios from
the Coupled Model Intercomparison Project (CMIP), Edurne Martinez
del Castillo has projected the developments likely to occur over the
next 70 years through to 2090. "Even assuming a relatively optimistic
climate change scenario, we will see sharp growth reductions of up to 30 percent in southern Europe between 2020 and 2050 compared to the 1986 to
2016 period," said the climate researcher. The optimistic climate model
assumes a temperature increase of one degree Celsius by 2090, while the pessimistic scenario predicts a warming of five degrees Celsius. The
latter would have dramatic consequences. Beech productivity would
decline sharply in much of Europe, by as much as 20 to 30 percent in most central European forests. "In southern Europe, losses could even exceed
50 percent," said Martinez del Castillo, noting that increased aridity
would affect the pattern. In contrast, in the north and in mountainous
regions, the growth trend would be positive. Overall, however, the gains
will not be as severe as the losses, neither geographically nor in terms
of absolute numbers.

In light of these forecasts, the authors of the study led by Edurne
Martinez del Castillo and Jan Esper believe that forest adaptation
measures are urgently required to mitigate serious environmental and
economic consequences. All the more so because beech forests act as
carbon dioxide sinks, and the reduction in tree growth is expected to
lead to further forest dieback, reducing this effect.


========================================================================== Story Source: Materials provided by
Johannes_Gutenberg_Universitaet_Mainz. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Edurne Martinez del Castillo, Christian S. Zang, Allan Buras, Andrew
Hacket-Pain, Jan Esper, Roberto Serrano-Notivoli, Claudia
Hartl, Robert Weigel, Stefan Klesse, Victor Resco de Dios,
Tobias Scharnweber, Isabel Dorado-Lin~a'n, Marieke van
der Maaten-Theunissen, Ernst van der Maaten, Alistair Jump,
Sjepan Mikac, Bat-Enerel Banzragch, Wolfgang Beck, Liam Cavin,
Hugues Claessens, Vojtěch Čada, Katarina Čufar,
Choimaa Dulamsuren, Jozica Gričar, Eustaquio Gil-Pelegri'n,
Pavel Janda, Marko Kazimirovic, Juergen Kreyling, Nicolas Latte,
Christoph Leuschner, Luis Alberto Longares, Annette Menzel, Maks
Merela, Renzo Motta, Lena Muffler, Paola Nola, Any Mary Petritan,
Ion Catalin Petritan, Peter Prislan, A'lvaro Rubio-Cuadrado,
Milos Rydval, Branko Stajić, Miroslav Svoboda, Elvin
Toromani, Volodymyr Trotsiuk, Martin Wilmking, Tzvetan Zlatanov,
Martin de Luis. Climate-change-driven growth decline of European
beech forests. Communications Biology, 2022; 5 (1) DOI: 10.1038/
s42003-022-03107-3 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220316115010.htm

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