Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mixed forests: ecologically and economically superior

09.05.2018

Mixed forests are more productive than monocultures. This is true on all five continents, and particularly in regions with high precipitation. These findings from an international overview study, in which the Technical University of Munich (TUM) participated, are highly relevant for forest science and forest management on a global scale.

"We know of the many advantages of mixed forests," states Professor Hans Pretzsch, co-author of the study and author of a recently released, internationally acclaimed book on the ecology and management of mixed-species stands. "Mixed-species forests are ecologically more valuable as versatile habitats. They mitigate climate change, as they mean a higher carbon sink."


Through their complementary crown and root systems, trees in mixed forests are often better supplied with light, water and soil nutrients.

Photo: L. Steinacker/TUM

Trees in mixed-species forests are often better supplied with light, water, and soil nutrients via their complementary crown and root systems. "This makes mixed stands more resilient during dry years. In addition, they are more stable against pests and visually more appealing," adds Prof. Pretzsch.

But these arguments alone have not yet managed to convince forestry management to promote mixed-species stands. This meta-analysis and overview study now shows that a prudent selection of the combination of tree species leads not only to more ecological and resilient forests, but also to greater productivity, explains Pretzsch.

The study documents that mixed stands perform better in terms of productivity than monocultures, particularly in areas with favorable water supplies, such as in Central Europe.

Meticulous data research

In cooperation with other forest scientists from France, Georgia, Switzerland, and Scotland, the TUM experts reviewed 600 studies which analyzed the influence of mixed forests on productivity. The yardstick used was the increase in volume of trunk wood which was calculated via repeated measurements of the tree diameter, height, and trunk shape.

From these studies, they filtered out 126 case studies in 60 areas on five continents which were published in 1997 and 2016. All these studies are based on long-term experiments for which regular measurements have been taken for decades, quite a few of which are in Bavaria.

More experimental areas for new forestry concepts

"Based on these findings, the interactions between the individual tree species will be studied in more detail at the TUM," states Pretzsch. The prerequisites for this are long-term experimental areas, which, in Bavaria however, have primarily encompassed monocultures in the past.

The forestry experiments in Bavaria are the oldest in the world, and provide a unique empirical data basis. As early as the 1870's, Permanent Secretary for Forestry August von Ganghofer (father of the author Ludwig Ganghofer) had experimental areas created with the conviction that only repeated analyses supply reliable information.

Most of those experimental plots are continuously measured till present, explained Pretzsch, who is the Head of the network of long-term experiments in Bavaria. The network of plots currently consists of over 1,000 individual areas, 80 percent of which are monocultures.

In the coming five years, they will be expanded with more than a hundred hectares of mixed stand experiments.

This mammoth project financed by the Bavarian State Ministry of Food, Agriculture and Forestry and the Bavarian state forests, BaySF, will provide important facts on the functioning and management of mixed stands in the future. "This will be highly interesting for science and provide practical decision-making aids," says Pretzsch. He is convinced of one thing: "In light of climate change and the increasing ecological, economic, and social requirements that forests need to fulfill, mixed stands will increase in importance throughout the world."

Publications:
H. Jactel, E. S. Gritti, L. Drössler, D. I. Forrester, W. L. Mason, X. Morin, H. Pretzsch, B. Castagneyrol: Positive biodiversity–productivity relationships in forests: climate matters.
Biology letters, British Royal Society, 14(4), 2017 0747 – DOI: https://doi.org/10.1098/rsbl.2017.0747

Hans Pretzsch, David I. Forrester, Jürgen Bauhus: Mixed-species forests, Springer-Verlag, 2017. ISBN: 978-3-662-54551-5 - https://link.springer.com/book/10.1007%2F978-3-662-54553-9

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

Weitere Informationen:

https://www.tum.de/en/about-tum/news/press-releases/detail/article/34635/

Dr. Ulrich Marsch | Technische Universität München

Further reports about: forests monocultures soil nutrients tree species water supplies

More articles from Agricultural and Forestry Science:

nachricht Researchers double sorghum grain yield to improve food supply
31.10.2019 | Cold Spring Harbor Laboratory

nachricht Game changer: New chemical keeps plants plump
25.10.2019 | University of California - Riverside

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: Magnets for the second dimension

If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.

Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...

Im Focus: A new quantum data classification protocol brings us nearer to a future 'quantum internet'

The algorithm represents a first step in the automated learning of quantum information networks

Quantum-based communication and computation technologies promise unprecedented applications, such as unconditionally secure communications, ultra-precise...

Im Focus: Distorted Atoms

In two experiments performed at the free-electron laser FLASH in Hamburg a cooperation led by physicists from the Heidelberg Max Planck Institute for Nuclear physics (MPIK) demonstrated strongly-driven nonlinear interaction of ultrashort extreme-ultraviolet (XUV) laser pulses with atoms and ions. The powerful excitation of an electron pair in helium was found to compete with the ultrafast decay, which temporarily may even lead to population inversion. Resonant transitions in doubly charged neon ions were shifted in energy, and observed by XUV-XUV pump-probe transient absorption spectroscopy.

An international team led by physicists from the MPIK reports on new results for efficient two-electron excitations in helium driven by strong and ultrashort...

Im Focus: A Memory Effect at Single-Atom Level

An international research group has observed new quantum properties on an artificial giant atom and has now published its results in the high-ranking journal Nature Physics. The quantum system under investigation apparently has a memory - a new finding that could be used to build a quantum computer.

The research group, consisting of German, Swedish and Indian scientists, has investigated an artificial quantum system and found new properties.

Im Focus: Shedding new light on the charging of lithium-ion batteries

Exposing cathodes to light decreases charge time by a factor of two in lithium-ion batteries.

Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory have reported a new mechanism to speed up the charging of lithium-ion...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

Smart lasers open up new applications and are the “tool of choice” in digitalization

30.10.2019 | Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

 
Latest News

Magnets for the second dimension

12.11.2019 | Machine Engineering

New efficiency world record for organic solar modules

12.11.2019 | Power and Electrical Engineering

Non-volatile control of magnetic anisotropy through change of electric polarization

12.11.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>