Report: Degraded Czech Forests Releasing Soil Carbon Into The Atmosphere

Like every member state, the Czech Republic is obliged to provide the European Union with detailed information on its carbon footprint. With this in mind, but also in an attempt to find local solutions and recommendations for the authorities, scientists are working tirelessly to study the various parameters of climate change. Martin Valtera from Mendel University is interested in soil carbon from Czech forests. As part of our new series on environmental research at Mendel University, Brno Daily’s Coline Béguet accompanied him for a day of fieldwork. Photo Credit: Coline Béguet / Brno Daily

Brno, June 5 (BD) – “The European Union promised, or declared, that we will be carbon neutral in the near future,” said Valtera, who works at Mendel University’s Department of Forest Botany, Dendrology and Geobiocoenology (FFWT MENDELU). “And the Green Deal is the mechanism to reach this goal. Within this framework, each country now has the obligation to report all its carbon information in detail. The Czech government therefore needs to have some information on soil carbon. They cannot say “we don’t know, we have no data”.” Indeed, each sector (industry, agriculture, forestry, etc.) has to provide precise scientific data on their carbon release and absorption. Valtera is a specialist in the characteristics and processes occurring in forest soils. He participates in a project headed by Radek Novotny, from the Forestry and Game Management Research Institute (VULHM), which focuses on forest soils, decomposition and carbon release. They collect and analyze detailed data on Czech forest soils, then report them to the government, “and our government will report our data to the European Commission.”

On Thursday, we leave at 7:30am with the university’s car. Before reaching the areas of forest chosen to be studied that day, we first stop at a DIY and gardening store to buy the missing equipment. Today, in order to prepare some experiments on wood decomposition, it will be necessary to collect samples in a new way, for which the shovels borrowed from the university are not sufficient. After spending an hour looking for the perfect rakes, screws and canvas bags, I realize that scientific research requires as many tips, tricks and gadgets as it does brilliant minds. The shopping session, and the assembly of the rake in particular, will be the most challenging part of the expedition, since, among other things, the screws sold by the shopping center are not compatible with the screwdriver available at the reception. “Nothing can surprise me anymore today,” says Valtera as he restarts the car an hour later and pulls onto the freeway.

Martin Valtera (left), his colleague Tomas Privetivy (centre), and Jan, a forestry student at MENDELU (right). Photo Credit: Coline Béguet / Brno Daily

“You see the forest?” asks Valtera when we enter a smaller road. I respond that yes, I do. “Enjoy! Because it will not be there for long,” he replies.

Indeed, a few hundred meters and jerks of the car over potholes later, the forest ends abruptly to make way for expanses resembling battlefields. We have to stop because a forest worker’s car is parked in the middle of the road, next to a tree stump decorated with a can of beer. He is busy in the middle of the last small group of trees that are still standing, and seem to have gathered in a small compact bunch to console themselves ahead of the inevitable death that awaits them. He can’t hear us, he’s busy working with a chainsaw on a tree that has just fallen. I take out my camera, then change my mind, somewhat worried about suffering the same fate as the unfortunate tree and ending up cut into pieces too. After a few minutes, we can finally pass and drive another few hundred meters before parking.

The ground is strewn with wood debris and every ten meters there are piles of branches several meters high. A few tiny fir trees try timidly to grow between the pieces of their missing elders. The reason for this massacre? Poor forest health. Since 2010 the climate has often been too hot and dry, which has considerably weakened the trees. In addition, this climate has favored the proliferation of bark beetles, tree-eating insects. These are natural parasites of spruces and they can defend themselves a bit, but not if the insects are too numerous and the trees already weakened.

A few tiny fir trees try timidly to grow between the pieces of their missing elders. Photo credit: Coline Béguet / Brno Daily

But was cutting everything really the only way to proceed? Valtera is skeptical. “They also used this as an excuse to harvest everything.” The price of wood has indeed recently increased and collecting wood in large quantities is therefore particularly profitable at the moment. Above all, the selective felling of diseased trees before they contaminated their neighbors would have averted the disaster. 

The “bark beetle calamity”, wood-eating insects that leave characteristic designs under the bark, has raged across Europe, but the Czech Republic has been hit particularly hard. Photo Credit: Coline Béguet / Brno Daily

The other problem is monocultures, especially spruces. Monoculture facilitates the work of foresters, since it doesn’t require an individual approach to each tree and allows a homogeneous growth of the forest. In addition, spruces have been planted in vast numbers throughout the Czech Republic because their wood structure is very good for construction and their cultivation is very profitable. But spruces are trees that only grow naturally in the mountains, at more than 1000 meters above sea level, and are therefore not suitable for all Czech regions. This explains their fragility and mass death in recent years. Greater variety in the forests and the use of endemic species would have averted the catastrophe. However, the deciduous trees naturally present in South Moravia, such as beech, oak, lime, maple or ash are less economically profitable and their wood is not suitable for all uses. Their structure is less straight and they have more branches. A diverse forest also requires more complex management and better trained foresters.

A dead forest eaten by Bark beetles. This situation has been understood by the general public as a natural disaster, without explanations or culprits, whereas it is rather the result of an accumulation of human errors. Photo Credit: Coline Béguet / Brno Daily

Finally, the large-scale collection of wood also reflects the desire to replace fossil fuels with renewable energies, and is therefore a clumsy movement towards more ecological policies. “That’s how our officials understand the Green Deal,” says Valtera, regretfully. “It is good to substitute concrete and plastics with renewable sources like wood… but if it means harvesting more in the forest it becomes a problem as well.” However, there is a solution; better, “close to nature” forestry, with selective and cautious harvesting could allow both goals to be reached at the same time, by decreasing the use of fossil energies and fabrics and simultaneously protecting the forests. This would require less extensive methods, such as the use of horses instead of huge trucks, better informed foresters, and a more individual approach to each forest and tree. Furthermore, in the long term, this type of approach is not much more expensive than current methods because the forest renews itself and it is therefore almost unnecessary to plant new trees.

A healthy forest with a diversity of species. Planting spruce as a monoculture in an environment that is not natural to them has made the forests vulnerable, even more so with climate change. A diversified forest, populated by endemic species, is much more resilient. Photo Credit: Coline Béguet / Brno Daily

Apart from the obvious importance of forest health for the animal world and biodiversity in general, forests also play a key role in fighting global warming. Trees are made up of 50% carbon, which they suck out of the atmosphere using energy from the sun, through the process called photosynthesis. 

The forest floor is not just able to absorb carbon as plants do, but can store even more of it, because of all the dead organic material that it contains: pieces of wood, branches, etc . Soil carbon is therefore of great importance in climate change science. After taking the brand new shovels and rakes out of the car to put on boots, we head to the first sampling location. Arriving at the location indicated by the GPS coordinates, Valtera begins to search, manual of the European research program in hand, for the exact place where the previous hole had been dug two years earlier. 

The heaps of branches and the holes left by the wheels of trucks do not make the task easy. The manual called “Monitoring of Air Pollution Effects on Forest” was originally created for, as its name suggests, the study of the effect of pollution on forests, before being used to analyze more parameters and processes occurring in the soil. Air pollution was indeed a major issue at the end of the 20st century. “I would not say it is not a problem anymore… but we now have bigger problems!” says Valtera. The bigger problems include the soil carbon released in the atmosphere. The guidelines provided by the manual for soil analysis and the samples taken are therefore now also used to study it, especially since the project for which this manual is used is “the largest continual monitoring network in Europe.” Valtera and his assistant Jan, a forestry student, start digging.

The presence of roots makes the work difficult and the soil becomes more and more dense at depth. Photo Credit: Coline Béguet / Brno Daily

There are two processes going on at the same time in forests: trees and all green organisms who absorb carbon from the atmosphere and animals, and microbiomes who release carbon into the atmosphere. And, “in these clearcuts, it’s the second process which dominates,” says Valtera, adding that this will continue until the vegetation has sufficiently reformed.

The forest floor is the first level, made of thorns, leaves and dead branches. It contains about 50% carbon. The second layer, called the top soil, is dark brown and contains about 15% carbon. The lower, larger and beige layers contain less than 3% and this proportion decreases as you go deeper into the ground. Photo Credit: Coline Béguet / Brno Daily

It is the upper layer of the soil, the forest floor, that contains the most carbon, about 50%, where plant waste accumulates. The deeper you go into the ground, the more the proportion of carbon decreases. This is why this first layer of soil is so valuable when it comes to fighting climate change. When the trees are cut down it finds itself naked and in full sun, which accelerates its decomposition and, through the activity of insects and the microbiome, releases large quantities of carbon into the atmosphere. In addition, the absence of vegetation means absence of carbon absorption. This is the reason for the next stops in our expedition: Valtera is responsible for a part of the project that consists of a decomposition experiment.

Each bag must be fixed to the ground carefully so that it remains in the same place for the duration of the experiment and is not moved by animals. The net allows small insects and microorganisms to pass through so that the rate of decomposition is the same as that of the surrounding soil. Photo Credit: Coline Béguet / Brno Daily

This experiment should bring this problem of the decomposition of the forest floor clearcuts to light and to better understand it. Small bags filled with branches and pieces of wood are placed in strategic places in order to monitor their decomposition. The main purpose is to assess how fast they decompose according to the microclimate: on plains, in clearcuts, in managed forests, in wild forests, and so on. This information, as well as the data collected in the big hole dug in the morning, will be used to provide recommendations on better policies. “What we do now in the forest is just a small piece of the puzzle,” adds Valtera. “There is a larger database with our partners.” Around 20 scientists, from institutions all over the country, are currently working on this project. Some part of the work happens in the university laboratory, where the carbon and microbial activity in the soil samples is assessed. We will find out how this part of the research works in the next part of Brno Daily’s series about research on environmental progress, to follow next week.

Wood debris collected from a clearcut where the trees were recently harvested was brought back to Mendel University for further experiments on wood decomposition. Photo Credit: Coline Béguet / Brno Daily.
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