Climate transformation affects all ecosystems of the planet, including forests. With global warming, they are becoming increasingly susceptible to fires, pests and pathogens. The director of the V.N. Sukachev Institute of Forest SB RAS, Alexander Onuchin, who visited TSU in the framework of the U-NOVUS 2021 forum described the situation.

Dangerous trends

- Alexander Aleksandrovich, could you tell us how Siberian forests “feel” in modern conditions? What factors influence them most?

- One of the main factors is global climate changes, first of all, an increase in temperature, which leads to a significant increase in fire hazard. The second factor which has the negative impact is insect pests and diseases (the development of root pathogens and others). They are also partly related to climate change. And finally, the trend which we are now observing is an increase in the concentration of carbon dioxide over Siberian forests. We are not yet able to reliably assess what contribution forest fires, degradation of permafrost, man-made and other factors make to this process. But research in this direction is already underway.

“There have been forest fires before. Are there more of them now?

- Yes, the trend of an increased number of forest fires is very noticeable. We are worried by the fact that it is more pronounced than the tendency for an increase in air temperature. We should say that in addition to the rapid change in the climate, another factor of the negative effect is added, which aggravates the situation - this is the imperfection of the forest protection system.

We do not have a reliable early fire detection system. When a fire is detected at the very beginning, it can be put out at once. But when the fire has already taken a disastrous scale, even with the involvement of all forces and means it can hardly be extinguished until it rains. Therefore, we need a reliable forecasting system for the occurrence of fires so that we can clearly identify hot spots where the probability of forest fires is the highest, and concentrate forces and means there, aimed, first of all, at detecting and then extinguishing fires.

One of our troubles is that the foresters were removed from the forest. This is a significant factor, and hence one can observe illegal logging, late detection of fires, outbreaks of pest activity, etc. Previously, at each site there was a forester taking care of a forest area and observing what was happening there.

But we do not have any foresters there. Modern forestry legislation is imperfect. It does not even have a concept of forestry, there is only timber harvesting mentioned there. As Academician Alexander Isaev used to say, “The forest is torn off the ground”. After all, the forest performs many functions, which are more important than being just a natural resource. The forest is both habitat and biodiversity, and even more. In forestry legislation, these things are not emphasized. And whether the code can be corrected with amendments is a big question.

- Alexander Alexandrovich, speaking at a round table at TSU, you said that now even those forests that did not burn before are burning now, for example, forests in the Arctic not far from the Arctic Ocean. What is the reason?

- The reason is the same - an increase in temperature, a decrease in precipitation. There are northern forests where the temperatures have never reached such a value at which forest vegetation begins to burn. And now this sum of temperatures has changed significantly, and fires occur almost on the coast of the Arctic Ocean. For example, fires occur in the northernmost forest area, Ary-Mas, which is located in Taimyr. There are other natural phenomena as well, namely the tundra burns more and more often, which we hardly observed before.

- Some experts say that not all fires need to be extinguished. Do you agree with this?

- It depends on where the fire occurs. It is imperative to extinguish fires near populated areas. It is also necessary to extinguish them in those areas where there are valuable forests, and biodiversity of animals. But if, for example, somewhere in a hard-to-reach place, a part of forest caught fire, and it is a grass fire, which can run into some natural obstacle, such as a river or another natural or artificial barrier, there may be no need to throw people there to extinguish it.

In order to make the right decision, there must be a fire forecasting system, which would provide an assessment of the necessary forces, means for extinguishing and possible damage. Such a system is being developed at the Institute of Forest, but currently this system operates only for certain regions.

To make such a forecast for other regions, forest inventory data is needed. In order to understand how the fire will develop, one needs to know, in addition to the meteorological situation, what kind of vegetation grows there. The problem is that there are few actual forest inventory data now, most forests were settled more than 20 years ago, and with time a lot could have changed there.

As far as carbon is concerned, different ecosystems (permafrost larch forests, shallow bogs, etc.) affect the structure of the carbon balance in different ways, and it is important for us to know quantitative estimates, so that we can appeal to the carbon balance in general and defend our interests in the global market in order to prove that even if our forests are burning somewhere, they play the role of a carbon sink rather than a carbon source.

How “to capture” more carbon

- Alexander Alexandrovich, one of the functions performed by forests is the absorption of carbon dioxide. In your speech, you said that the concentration of CO2 over Siberian forests is growing. What is the reason for this?
- Indeed, our research at the station near Zotino shows that the concentration of greenhouse gases in the atmosphere is increasing. This applies to both methane and carbon. But I cannot tell you the specific reasons for this phenomenon yet. Both the increased frequency of fires and transboundary transport can affect this. The atmosphere is an open system, so the air currents containing these gases can come from different countries such as China, America ... Now we are conducting research with our partners which will assist in identifying the impact factors. New observatories are being established, including those for determining the direction of flows.

- Can the carbon sequestration capacity of forests be improved?

- It is possible, because forests affect carbon sequestration in different ways. For example, in the north, the forest is not productive, as it produces little biomass and oxygen. But the balance of such a forest is positive: the carbon which it absorbs does not go into the atmosphere. Basically, everything is accumulated in the soil or enters the ocean with runoff, being deposited for many years, and then it is actually withdrawn from the atmosphere. With tropical forests, the story is different: they have extremely high productivity, a huge increase in biomass, which gradually decomposes. There, microorganisms (soil bacteria etc.) function very actively, and in this case, carbon is released into the atmosphere. Therefore, despite the high productivity of the forest, the balance there is zero: the carbon absorbed by the forests, is completely released.

At our institute, we have developed technologies to enhance the carbon-sinking functions of managed forests. Improving carbon sequestration in northern forests can be achieved through proper maintenance which would lead to a multiple increase in the absorption of carbon dioxide used by trees as food, and to a higher increment of wood. For example, usually pine forests give us an increase of 10 cubic meters per hectare (per year), but this is precisely during the period of good growth - when the trees are from 15 to 60 years old. If care is taken, the growth increases from 10 to 20 cubic meters per hectare, and the period of good growth is extended to 90-100 years rather than 60.

- Alexander Alexandrovich, what does the care about forests mean?

- There are different technologies, including sanitary felling. This is roughly analogous to what we do in our gardens - we thin out crops and remove weeds so that the sprouts do not interfere with each other. The forest grows in almost the same way and without care, over time, intraspecific competition greatly increases. That is, with special care, we can have a targeted effect on the productivity of the forest and carbon-sequestration function.

- Alexander Alexandrovich, and one more question regarding forestry and technologies. What approaches can be developed to help the forest adapt to climate change?

- There are different approaches. Modern technologies make it possible to create new plant species with improved characteristics. For example, our geneticists have created a species of larch which is resistant to most diseases typical for it. Micropropagation technology, mastered at the Institute of Forest, allows obtaining seedlings of good quality in a short time. Thus, it is possible to purposefully create forests which are resistant to various pathogens. On the other hand, it is possible in nature to find genetically improved tree species resistant to pests and various stress factors, which will be able to grow well even under conditions of the rapid climate change.

Background information: Tomsk State University has initiated the formation of the consortium "Global Earth Changes: Climate, Ecology, Quality of Life". Its structure will include about 15 leading scientific centers of the country engaged in the study of climate change and its impact on the transformation of the environment. The global task of the consortium is to develop mechanisms for adaptation of humans and ecosystems to climate change and its consequences. One of the first members of the new association is the V.N. Sukachev Institute of Forest SB RAS. The cooperation agreement was signed at the forum ‘U-NOVUS 2021’.

Source: Tomsk State University.