Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Trees and climate change: Faster growth, lighter wood

14.08.2018

Trees are growing more rapidly due to climate change. This sounds like good news. After all, this means that trees are storing more carbon dioxide from the atmosphere in their wood and hence taking away the key ingredient in global warming. But is it that simple? A team from the Technical University of Munich (TUM) analyzed wood samples from the oldest existing experimental areas spanning a period of 150 years – and reached a surprising conclusion.

The team led by Hans Pretzsch, Professor for Forest Growth and Yield Science at the TUM, examined wood samples from several hundred trees and analyzed every single annual ring using a high-tech procedure — a total of 30,000 of them.


High-frequency probe of the LIGNOSTATION when scanning a wood sample.

Picture: P. Biber/ TUM

"The heart of the LIGNOSTATION is a high-frequency probe which scans each sample in steps of a hundredth of a millimeter", says Pretzsch, explaining the analysis procedure. "By doing so, we measure the specific weight of the wood with an accuracy and resolution which until recently was unthinkable."

The wood samples come from the oldest experimental forest plots in Europe which were created at the same time the TU Munich was founded 150 years ago. The samples were taken from common European tree species such as spruces, pines, beeches, and oaks. "We have detailed knowledge of the history of every single plot and tree", says Pretzsch. "This allows us to rule out the possibility that our findings could result from the forest being managed differently now as compared to a hundred years ago."

Climate change is making the wood lighter

With the combination of wood samples from the 1870s to the present day coupled with the latest measurement technology, the team at the School of Life Sciences Weihenstephan were able to demonstrate that the annually growing wood has gradually become lighter since observations began: By up to eight to twelve percent since 1900. Within the same period, the volume growth of the trees in central Europe has accelerated by 29 to one hundred percent.

In other words: Even though a greater volume of wood is being produced today, it now contains less material than just a few decades ago. However, the explanation which immediately comes to mind does not apply.

"Some people might now surmise that the more rapid growth could itself be the cause for our observations", says Dr. Peter Biber, co-author of the study — "In some tree species, it is in fact the case that wider annual rings also tend to have lighter wood. But we have taken this effect into account. The decrease in wood density we are talking about is due to other factors."

Instead, Pretzsch and his team see the causes as being the long-term increase in temperature due to climate change and the resulting lengthening of the vegetation period. But the nitrogen input from agriculture, traffic, and industry also play a part. A number of details lead experts to surmise this, such as the decrease in the density of late wood and the increase in the percentage of early wood in the annual rings.

Lighter wood – What's the problem?

Lighter wood is less solid and it has a lower calorific value. This is crucial for numerous application scenarios ranging from wood construction to energy production. Less solid wood in living trees also increases the risk of damage events such as breakage due to wind and snow in forests.

But the most important finding for practical and political aspects is that the current climate-relevant carbon sequestration of the forests is being overestimated as long as it is calculated with established but outdated wood densities. "The accelerated growth is still resulting in surplus carbon sequestration", says Pretzsch. "But scaling up for the forests of central Europe, the traditional estimate would be to high by about ten million metric tons of carbon per year."

More Information:
The research group at the Chair for Forest Growth and Yield Science at the TUM School of Life Sciences Weihenstephan led by Hans Pretzsch investigates the effect of climate change on the growth, stability, and vitality of trees. An important basis for this research are the experimental plots of the Chair, on which the dynamics of forests have been measured since 1879 to answer ecological and economic questions. In the study reported here, they contribute to measuring the human footprint in forest ecosystems.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Hans Pretzsch
Technical University of Munich
Chair for Forest Growth
Phone: +49 (8161) 71 - 4710
Mail: hans.pretzsch@tum.de

Originalpublikation:

Pretzsch, H., Biber, P., Schütze, G., Kemmerer, J. and Uhl, E.: Wood density reduced while wood volume growth accelerated in Central European forests since 1870, Forest Ecology and Management, Volume 429/2018. DOI: https://doi.org/10.1016/j.foreco.2018.07.045

Weitere Informationen:

https://www.tum.de/nc/en/about-tum/news/press-releases/detail/article/34892/

Dr. Ulrich Marsch | Technische Universität München

Further reports about: Forest Ecology TUM Trees Weihenstephan carbon sequestration forests tree species

More articles from Agricultural and Forestry Science:

nachricht Interaction with fungus containing N2-fixing endobacteria improves rice nitrogen nutrition
26.11.2019 | American Society of Plant Biologists

nachricht Strengthening regional development through old growth beech forests in Europe
20.11.2019 | Hochschule für nachhaltige Entwicklung Eberswalde

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Developing a digital twin

University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making

In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...

Im Focus: The coldest reaction

With ultracold chemistry, researchers get a first look at exactly what happens during a chemical reaction

The coldest chemical reaction in the known universe took place in what appears to be a chaotic mess of lasers. The appearance deceives: Deep within that...

Im Focus: How do scars form? Fascia function as a repository of mobile scar tissue

Abnormal scarring is a serious threat resulting in non-healing chronic wounds or fibrosis. Scars form when fibroblasts, a type of cell of connective tissue, reach wounded skin and deposit plugs of extracellular matrix. Until today, the question about the exact anatomical origin of these fibroblasts has not been answered. In order to find potential ways of influencing the scarring process, the team of Dr. Yuval Rinkevich, Group Leader for Regenerative Biology at the Institute of Lung Biology and Disease at Helmholtz Zentrum München, aimed to finally find an answer. As it was already known that all scars derive from a fibroblast lineage expressing the Engrailed-1 gene - a lineage not only present in skin, but also in fascia - the researchers intentionally tried to understand whether or not fascia might be the origin of fibroblasts.

Fibroblasts kit - ready to heal wounds

Im Focus: McMaster researcher warns plastic pollution in Great Lakes growing concern to ecosystem

Research from a leading international expert on the health of the Great Lakes suggests that the growing intensity and scale of pollution from plastics poses serious risks to human health and will continue to have profound consequences on the ecosystem.

In an article published this month in the Journal of Waste Resources and Recycling, Gail Krantzberg, a professor in the Booth School of Engineering Practice...

Im Focus: Machine learning microscope adapts lighting to improve diagnosis

Prototype microscope teaches itself the best illumination settings for diagnosing malaria

Engineers at Duke University have developed a microscope that adapts its lighting angles, colors and patterns while teaching itself the optimal...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

 
Latest News

Solving the mystery of carbon on ocean floor

06.12.2019 | Earth Sciences

Chip-based optical sensor detects cancer biomarker in urine

06.12.2019 | Life Sciences

A platform for stable quantum computing, a playground for exotic physics

06.12.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>