Wood has been used by humans since the earliest civilisations, and in the quest for renewable materials and energies, it would appear to be an ideal resource if it did not cast the shadow of deforestation. Indeed, forests are known as the lungs of the planet and it is the worst possible time to get rid of them. Faced with this paradox, there is hope for a solution: sustainable, close-to-nature forestry. As part of our series on environmental research at Mendel University, Brno Daily’s Coline Béguet explored the different parts of the practical and experimental work done in the 10,000-hectare Mendel University forest enterprise. Photo credit: Coline Béguet / Brno Daily
Czech Republic, Aug 31 (BD) – The historic forest fire that ravaged the České Švýcarsko nature reserve could not have escaped anyone’s attention, nor the calamity of the bark beetles which have laid waste to Czech spruce forests. These incidents are the direct consequences of the rising temperatures and long periods of drought that global warming is inflicting on forests all over the world. The trees, battered by the heat and the lack of water, are weak, dehydrated and are therefore highly flammable and struggle to defend themselves against the attacks of bark-eating insects.
To address and anticipate the consequences of climate change in Czech forests, Tomas Vrska, a renowned former researcher and now director of the Mendel University’s forestry enterprise, recommends replacing the monocultures of conifers, certainly very profitable, but fragile and of less resilience in terms of biodiversity, by mixed forests. Mixed, or uneven-aged forests, as Vrska explained to us in an interview earlier in the series, means not only the mix of species, but also of ages and density. This type of forest is not only closer to natural forests but also more resistant. The different strengths and weaknesses of each tree make the forest as a whole more resilient to extreme and capricious weathers.
If adapting to these inevitable and already current upheavals is no longer an option, slowing down climate change by limiting our greenhouse gas emissions remains essential, and this challenge of our century must be considered in all its dimensions, wherever there is room for maneuver. Along with reducing our consumption by transforming our societies to a more sustainable way of life comes the replacement of fossil energies and materials with renewable and ecological ones. Wood is a great, multi-purpose material which offers an alternative to petroleum in many situations. It allows us to heat, to dress, to build houses or to create furniture and many kinds of objects.
A wonderful material, but what to do as our forests are the lungs of our planet? While you are reading this, at a time when we need our forests more than ever for their ability to capture carbon from the atmosphere and put it back in the ground, it doesn’t seem like a great idea to cut them down. And what to do when the cutting of trees often leads to clearcuts which leave fauna without shelter and the soil of the forests, so fragile and so precious in the resistance against the greenhouse effect, to decompose in the sun?
“Sustainable means that you keep the forest cover on the whole area and you don’t lose it”
Lumír Dobrovolný, head of the development and pedagogy department of Mendel University’s forest enterprise, insists that harvesting the wood is not a problem in itself, but that it all depends on how it is done. In order to avoid clearcuts and their terrible consequences, it is first necessary to rethink the methods of cutting and collecting wood. “Sustainable means that you don’t lose the forest area. You keep the forest cover on the whole area and you don’t lose it,” explains Dobrovolný.
“We use different sylviculture models,” he continues. “We have models which are more original or traditional, which should be adapted to climate change. More close to nature. We want to show students all models, all possibilities, so we divided the whole property in different sylviculture models. This is our main purpose: education in forestry and being a laboratory for research, for the academic staff of our university. We also do what we call forest pedagogy, we try to educate the public, the children. And, the main goal for us is to transport the theoretical from the faculty to practice.”
“So we divided the whole property into many parts where different sylviculture models are put into practice,” explains Dobrovolný. The 10,000 hectares of forest belonging to Mendel University and located in the north of Brno are divided into multiple categories and subcategories where different types of forest exploitation are tested and evaluated. “First, the traditional model, which consists of cutting in belts, or in strips. This is not sustainable and not good for climate change, but we still do it, because we want to show all variants and compare economical production and ecosystems… We need to compare everything!”
In this traditional model, where even-age monocultures are planted at regular intervals, often in lines and at the same time, the forest is too dense and there is high competition for the water and nutrients. The trees are therefore not prepared for climate extremes such as strong winds or long dry periods. Also, the traditional model involves cutting in belts, or in strips. “If you do this clearcutting you open the forest too much, you open the soil and you open also the forest area, so the sunlight and the heat come into the forest and totally change the microclimate here,” says Dobrovolný.
In the sun, the topsoil and forest floor, the first two layers of soil, decompose more quickly, releasing large amounts of carbon into the atmosphere and making it more difficult for the next generation of trees to regrow. Also, “there are thousands, millions kilometers of fungus which are growing in symbiosis, in connection with trees. They help each other: the trees help the fungus to water and the fungus help the trees with nutrients,” Dobrovolný adds. “They are connected together and if you do these strips, clearcuts, you lose, destroy everything. This is the next argument for this individual, small selection.”
In past times, this traditional model was used in 90% of the Mendel University forest enterprise area. “Now we have changed it, we mostly use dauerwald management, which is from a German word that means permanent forest, and the freestyle sylviculture technique. It means we don’t make these strips, but cut them in small groups or individually. Foresters go and don’t make any clearcut, any strip, but make an individual selection.” When these more sustainable models are used, the cut is not only important for wood and profit, but also because it releases space for the next generation of the forest. “Your release space, you create a way for forest regeneration.”
For this, each tree must be chosen carefully and its cutting duly considered. As trees grow taller and thicker, competition among them for water and light increases. Foresters select the “best” trees, those with the greatest potential for future use. They are often the straightest and most compact because their wood can then be used to build homes or furniture.
In order to give them the best conditions to develop to their full potential, trees that are too close to them are removed and used for more modest purposes, such as making small objects, paper or even fuel. In the space created, the selected tree can grow easily, but also young trees can be planted. They are initially too small to harm it, but will then replace it in a few decades, when the time comes for it to be harvested in turn and become a chalet or a desk.
The profession of forester in sustainable forestry therefore requires solid training, a keen sense of observation and time for reflection. Indeed the individual cut, once the trees have been selected, must still be the subject of a complex geometric calculation so that the tree, by falling, does not damage the others. A notch should be made in the exact direction the forester wants the tree to fall, before being sawed from the opposite side. The fall is then carried out using a lever and a hammer.
But sustainable harvesting does not stop there: it is also necessary to bring the wood back to the sawmill without causing damage to the ecosystem. The wheels of trucks and tractors inflict severe and lasting damage to the forest floor, mixing its layers, destroying the fragile net of fungus and complex symbiosis between them and the trees, and digging ditches.
A first alternative, possible if the trees are sufficiently spaced, is to cover the ground with branches before the passage of vehicles in order to protect it. In addition, these branches, by decomposing, will leave important nutrients for the next generation of trees. Another possibility, which allows vehicles to stay on the road and avoid entering the forest, consists in removing all the branches from the trunk directly where it has fallen, before securely attaching it to a chain and transporting it towards the road with a pulley system using other trees.
Finally, for the most fragile or inaccessible portions of the forest, the forestry workers can use the help of imposing draft horses to pull the logs to the road. “So far we have two, which is good enough, but I’d be happy to have some more,” says Vrska. Unsurprisingly, horses turn out to be much more environmentally friendly than motor vehicles. They not only release much less gas into the atmosphere, but also weave their way through vegetation without damaging it, disrupting the ecosystem, or turning the soil upside down. The problem, explains Vrska, is not only that horses are expensive, but also require those who work with them to adapt their way of life. “If you work with a horse, you have to get up at 4am, feed it, clean its space, and take it to the forest stand where it has to work. It’s a way of life, not everyone is willing to adopt it.” More restrictive indeed than turning the ignition key of a tractor.
to the road in hard-to-reach areas without damaging the ecosystem. Photo credit: Coline Béguet / Brno Daily
Above all, however, in order to maintain forest cover, it is essential to ensure more wood is not cut than is growing. Here again, scientific progress intervenes, as complex calculations allow ever more precise estimates of the increment volume. “The simple principle is that the forest is constantly growing; every second trees grow in diameter and in height, and that means growth in volume.” So the sustainable forest enterprises need to calculate the increment per year and per hectare. This requires an inventory of the whole forest, and from this data the volume that can be cut is calculated. For example, “we know that the increment of our whole university forest enterprise per ten years is 700,000 cubic meters of wood. So we know this increment, and we cut only this increment. Nothing else. If you do this management, it is sustainable, you don’t have clearcuts and you don’t lose forest cover.”
Two main ways for the forest to regenerate
“There are two ways of doing that: artificial regeneration, which means planting and natural regeneration from the seeds. We also owned a nursery, the place where we cultivate the seedlings, where we make new seedlings for planting,” explains Dobrovolný. This method is necessary after a clearcut to help the forest to regrow, and is the method used in traditional sylviculture models. It is also necessary when it comes to transformation of a monoculture to a mixed forest, to introduce the diversity of tree species.
However, this method requires a lot of time, effort and money, about half a million crowns per hectare for the process from the clearcut to adult trees. “You need to cut the grass and the vegetation around the seedling to reduce the competition for light, water and nutrients. You have to take care of this regeneration.” It is also necessary to protect the seedlings against deer and to build fences around the young trees, especially around tree species appreciated by the ungulates. “Deer love silver firs, but we foresters love them too, so we need to find some compromise solutions,” jokes Dobrovolný.
Finally, these little trees, first grown under greenhouses and generously watered and fed with nutrients, are spoiled kids and struggle to adapt to the forest after being replanted. Since they have spent the first months of their life in pots, their root system has also been strained and malformations may remain. All of this makes them more fragile and slower to grow than their wild comrades. The other option is to rely on natural regeneration, made possible by selective cutting and close-to-nature forest management. If the costs of sustainable logging are higher at the time of harvesting, due to the multiple precautions and the necessary know-how, they are compensated by this possibility of using the natural regeneration potential of the forest, almost free of charge.
