The number of hardy trees has increased eightfold. How can their lack be one of the causes of biodiversity loss? A recent study goes through this contradiction.
Forest land the area has increased in Finland. The volume of the stand has almost doubled. The growth rate of forests has accelerated. There are also more and more sturdy trees in the forests. In southern Finland, the amount of rotting wood has increased.
All of this information appears unanswered from the National Forest Inventory Monitoring System (VMI), whose time series span more than a hundred years.
At the same time, the data in the Red Book assessing the endangerment show that forest nature can be shaky. When looking at forests as habitats, three out of four different forest habitats are endangered. When looking at forest species, almost one in ten organisms is endangered. The deforestation of forests is progressing.
How is it possible that forests are growing noisy but at the same time their nature is dwindling? The professor of ecology at the University of Jyväskylä began to explain this paradox Mikko Mönkkönen with eight other researchers. Results of the study was released on Thursday.
Forest roof in Mäntsälä.
Sturdy pine in the opening of Keuruu.
One Mönkkönen’s goals were to find scale and perspective For the national forest inventorybecause its results are widely used as justifications in the Finnish forest debate – even when the debate concerns the loss of nature.
“I have been confused in the Finnish forest debate that it is stated how, according to the VMI data, the number of large trees has increased eightfold in southern Finland, and then it is said that the diversity problem has now been solved,” Mönkkönen explains.
When planning to protect forest nature, relying on VMI is problematic for a couple of reasons.
First, many inventory metrics provide good information to support timber production, but there are fewer tools for estimating biodiversity loss. Of course, the inventory includes important indicators for the richness of forest nature, such as the proportion of deciduous trees, the age classes of forests and the amount of decaying wood. The inventory has also tried to meet the demand for natural data: for example, the assessment of blueberry cover has been included as a new one.
Another problematic point is the time span. One hundred years is a short time in the woods. Forest data have been measured since 1921.
This leads to the third problem. In the 1920s, forests were already far from natural, meaning measurements do not provide comparative information about what our forest nature would be like naturally. In the early 20th century, forests were even more fertile and consumed than they are now.
Commercial forest spruce in Padasjoki.
Home primeval forest in the Evo conservation area in Häme. The area’s forests have been protected since the early 20th century.
If wants to know what the rich, ashless Finnish forest nature is like, you have to move your gaze further. Much longer.
The International Union for Conservation of Nature (IUCN) has chosen 1750 as the reference area for endangerment classifications.
The year is also a good benchmark for Finland, as population growth in Finland accelerated at that time. At the same time, settlement and other human influence spread to forests more widely than before.
However, there was no longer a natural forest in Finland even in 1750. Therefore, Mönkkönen and his research colleagues have taken as a reference both the features of a natural coniferous forest and the situation in 1750.
What did the researchers find in their comparison? At least the fact that the improvements seen in the kingdom’s forest inventory are tiny when put into perspective.
A few pictures are worth looking at.
Decaying wood the number in southern Finland has indeed increased by 61 per cent in twenty years. The growth has largely taken place in protected areas.
Although the percentages are large, there is only 4.5 cubic meters of decaying wood per hectare in the forest in southern Finland and even less in commercial forests. It is a lean comfort, when in a natural old forest there can be 110 cubic meters of decaying wood per hectare – that is more than 20 times the amount.
“Although the number of rotting trees has risen a bit, it is far from what the needs of organisms are. And leaving rotting wood in the forest competes directly with forestry. The more biomass is taken out of the forest, the less it is left to rot in the forest. In that sense, this is not a win-win situation, but a clear conflict, ”says Mönkkönen.
The same goes for the number of solid trees. Although it has increased eightfold in southern Finland and almost doubled in Finland as a whole, the number is still less than one-fifth of the number of heavy trees in the natural forest.
In addition researchers found that sheer harsh is a poor measure of natural survival.
The trees have become stiffened because the warmer climate, fertilization and tree breeding have accelerated the growth of the trunks. However, many species need slow-growing and old hardy trees. And their number has not grown in the same way – on the contrary.
In southern Finland, perhaps one of the two large trees is on two hectares, while in natural forests there could be 40–120 of them in the same area, says Tree dwellers book (2021).
Although the national forest inventory shows that the number of old (over 150 years old) tree species in southern Finland has increased by almost 60 per cent, they are still less than one tenth of what old trees were in natural forests. The graphics seen above do not show this, but illustrate the proportion of trees over 120 years old in the whole of Finland.
Even the increase in the area of vegetated forest land is not unequivocally good news for nature. More forest has been obtained by ditching bogs. It has meant millions of acres of ruined marshland.
Metsäoja in Janakkala, Häme.
Decaying wood in a nature park in Padasjoki, which is forbidden for hikers.
An aspen about two meters in circumference in Vuohiniemi, Mänttä-Vilppula. Jussi Kumpula and Ari Aalto assessing the size of the wound.
In its current condition Finnish forests are therefore very far from natural. In other words, they are far from the conditions to which animals, plants, and fungi have adapted during their evolutionary history.
The change has been drastic and sudden: it has taken place in almost all forests and in only about one generation of trees.
This is the cause of extinction and the loss of nature. Forest habitats are disappearing, and the remaining ones are becoming more similar, monotonous, becoming different. At the same time, species are disappearing.
And not everything has been seen here yet. As habitats change, species begin to disappear with a delay. Therefore, extinctions will be seen even more in Finland if the one-sidedness of forest habitats cannot be reversed.
The improvements of recent decades seen in the national forest inventory are thus the worst of small recovery. But it is not an improvement on the state of nature or even the situation of 1750, but perhaps the darkest phase of our forests.
At the beginning of the 20th century, there were already sawmills in Finland and the pulp industry also took its first steps. On the other hand, tar burning was still practiced, as was cascade.
“Somewhere in those mains has been the poorest Alho in the woods. Forests were used very extensively for various purposes. When the strong open logging economy started in the 1940s and 1950s, it has slowed down the low recovery, ”says Mönkkönen.
Improvements compared to that low are so small and so far from what kind of forests our organisms have adapted to that they cannot be said to be sufficient to safeguard the forest nature. So they are not even enough to preserve the current spectrum of nature, let alone restore the former wealth.
“We are still losing a lot of diversity, because there is a delay in the extinction of species,” warns Mönkkönen. Therefore, small improvements cannot be overemphasized.
“The results of the national forest inventory have been interpreted without a broader perspective. Conclusions have been drawn that remedial action has now been taken and it is no longer necessary to wait for the situation in the forests to begin to improve. It was also suggested at the VMI 100 seminar that the Natural Resources Center should smoke openings from the universities, because the results show that the problem of natural loss has been solved. ”
Mönkkönen says that the study completed now confirms previous observations and conclusions about the poor state of Finnish forest habitats.
“In part, the new results point to an even more dramatic decline in forest nature, looking now at the history of forest nature across the country beyond the past couple of hundred years.”
Naava or loupe on a decaying tree in a nature park in Padasjoki.
Sinitiainen in the forest of Alvojärvi in Lahti.
Their research Mönkkönen considers it clear that both protection and the natural management of commercial forests must be increased if the loss of nature is to be halted. The law on deforestation should also be amended: the law now prohibits leaving more than ten cubic meters of fresh rotting wood per hectare in commercial forests.
What then would there be a sufficient number of improvements to the state of the forest nature? Sufficient amount of decaying wood, sufficient number of old tree species, sufficient number of solid trees, sufficient number of deciduous trees?
“This is just being investigated. Maybe in a few years we will get results from this too. But now it is not possible to say any figures based on the research, there is no known safety limit by which the loss of nature in the forests could be stopped, ”Mönkkönen says and continues:
“The answer also depends on what we are aiming for, how diverse the forest we want. It can be said that if we want to preserve the diversity inherent in Finland, the bar is far away and there is a lot to do. ”
Alvojärvi forest in Nastola, Lahti.
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