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Protecting dry forests is synonymous with protecting the climate

Matthias Baumann investigated the accelerating deforestation of the South American Gran Chaco in a joint study with colleagues form Argentina and from the HU research institute IRI THESys.

Gerodete Fläche im Argentinischen Chaco

Deforestation of the Gran Chaco. Figure: privat

Matthias Baumann is a postdoc at the Geographical Institute at the Humboldt-Universität zu Berlin (HU). After completing his degree at the HU he went to the University of Wisconsin-Madison and he returned with a PHD in 2014. Since then he has been doing research under the supervision of Prof. Tobias Kümmerle in a team of approx.10 researchers at the Conservation Biogeography Lab. Here the focus is on questions pertaining to global land-use change and coupled human-environment systems.

Most recently, Matthias Baumann investigated the accelerating deforestation of the South American Gran Chaco in a joint study with colleagues form Argentina and from the HU research institute IRI THESys. The Gran Chaco is a region made up of dry forests, thorn bush savannahs and grasslands within South America. With around 1.1 million square kilometres, it covers parts of Bolivia, Argentina and Paraguay. The scientists wanted to find out how deforestation of the Chaco forest and the expansion of grazing and soybean acreages influence CO2 emissions and therefore have a negative impact on the climate. The study recently appeared in the renowned specialist journal Global Change Biology. In October of last year, the group travelled in the Chaco and they brought with them new findings as well as the motivation for a follow-up study.

Mr Baumann, what made you choose to examine a tropical dry forest in terms of climate impact?

Previously, global climate debates focused on the deforestation of tropical wetland forests for the most part and the Amazonas in particular. Accordingly, efforts were made to limit deforestation here and thus reduce the emission of greenhouse gases - in some cases with enormous success.

Until now, only the scientific community was aware that the destruction of tropical dry forests also impacts on our climate. To this effect, barely any measures were taken to protect such forests in the past.

Dr. Matthias Baumann

Dr. Matthias Baumann. Figure.: privat

Please generally explain again: Why does the deforestation of the forest have a negative impact on the climate?

The forest is burned after forest clearance in order to create agricultural land and this is especially the case when the wood cannot be used for further processing. That is more cost-effective and faster than transporting it. During the burning process, carbon which is stored in the vegetation in leaves, branches, logs and roots, is released. As a result of deforestation, the same greenhouse gas is produced as that during coal combustion, for example.

Due to the large quantities which are released, we now know today that the land-use change in addition to the combustion of fossil energy sources, is one of the driving factors of climate change.

What role does the Gran Chaco play in this context?

In our study, we identified the Gran Chaco as a hotspot of global deforestation. We have been able to point out two developments that occurred during the last 30 years: On the one hand, more than 20 percent of the forest in the Chaco has been lost. That is twice the surface area of Bavaria. Cattle now graze there for meat production, monocultures are mostly cultivated on the rest of the land. On the other hand, 40 percent of the grazing areas which already existed have been transformed into crop areas – particularly for soy. The soy is shipped to Europe and China and here it is primarily used for animal fattening so as to satisfy the constantly increasing hunger for meat.

So there are two developments in the Chaco: The expansion and intensification of agriculture. With what effect?

In essence we were able to demonstrate that the resulting greenhouse gas emissions in the Chaco are of a similar magnitude as those in the neighbouring deforestation hotspots in the tropical rainforest.

That alone astounded us because in the latter case, there is significantly more carbon stored in the vegetation. In this respect, our results are also an indicator for how fast deforestation is progressing in the Chaco.

The main problem with 60 percent of the collective emissions is the transformation of forest into cattle pastures but the subsequent transformation of grazing areas into soy bean fields also has a strong influence.

Intakter Wald: Der Habitat für Gürteltiere, Wildkatzen und Schlangen.

The Gran Chaco. Figure: privat

How did you proceed in the study and how did you calculate the emission levels?

We evaluated satellite images in the period between 1985 and 2013. This way we were able to reconstruct the course of the deforestation front, so we could see how the core of the Chaco has been cleared from various external positions. The outcome was maps and graphs which, in turn, enable conclusions to be drawn about the causes and solutions. We then calculated, by mean of a carbon model, how the land-use change contributes to the carbon balance.

So what can be done?

Clarification and information, describe the problem and bring it to the attention of the public. We have a clear objective of using the study to point out the danger posed by the disappearance of tropical dry forests. That is relevant to us all.

When the international community is aware of the problem, then it is also possible to take action – therefore, for example, establishing protected areas based on the model of the tropical wetland forests. Previously, there have been far too few protected zones in the Chaco: On the whole, only 15 percent of the area is protected and it is a mere 3 percent in the Argentinian part.

It is often the case that economic interests take precedence over conservation in the Chaco. That is something we experienced first-hand: We could have bought forest for 3,500 dollars per hectare including forest clearance. The state should impose more taxes here.

Will you continue to work with the Chaco in the future?

Our journey there highly motivated us to develop the study. The current study was carried out from a quantitative perspective and therefore we relied on data. In the next study we would like to combine our information with socio-scientific enquiries – hence holding talks on-site with those who own and use the areas. This way we can refine our material with a view to improving documentation and understanding of how deforestation progresses.

The interview was conducted by Christin Bargel – press officer at the HU

About the study

Baumann, Matthias et al. (2016). Carbon Emissions from Agricultural Expansion and Intensification in the Chaco. Global Change Biology. Available online.

Further Information


Matthias Baumann
Postdoctoral Researcher
Humboldt-Universität zu Berlin

Phone: 030 2093-9341