Efficacy of biodiversity maintenance supported by research

3.6.2008 / Article

A study on threatened biotopes in Finland has found biodiversity in all commercial forests regardless of their age. This shows support for biodiversity maintenance.

A research project led by the Finnish Environment Institute concerning the threats to the Finnish biotopes was started in 2003, and the results will be published today. The principles of defining the threats were published earlier.

One of the results of the study, that the area of natural forests in Finland is small, should come as no surprise to anyone. Another result is that there is biodiversity in commercial forests of all ages.

”In this regard the research brings nothing new to developing the maintenance of biodiversity in commercial forests. By now, biodiversity maintenance has been a part of the management of commercial forests of all ages for 15 years,” says Mr. Timo Lehesvirta, environmental manager of UPM Metsä.

UPM Metsä is the division of UPM that looks after the company’s forests in Finland. For a long time, UPM Metsä has systematically developed the methods of biodiversity maintenance in commercial forests in Finnish conditions.

High figures will spark off discussion

Lehesvirta believes that the study will be widely discussed. He is seconded by Mr. Petri Heinonen, environmental manager at the state-owned forestry company Metsähallitus.

“Researchers and forestry professionals are confused about the new forest type classification created as part of the study. It was developed by combining the age class of the forest biotope with the biotope classification system created by the Finnish forest researcher A. K. Cajander. This may make it easier to see the opportunities for biodiversity maintenance in commercial forests,” says Heinonen.

Another point of interest is likely to be the calculation of the extent of threatened biotopes. The study states, for example, that in southern Finland “the share of threatened forest biotopes of the total forest area” is 49 percent, on the basis of an overall estimate .

The estimate is, however, theoretical. The high figure is based on a method which regards all instances of threatened biotopes as threatened, although only certain number of them actually are that. As a result, the instances of threatened biotopes on strictly protected lands, for example, are considered threatened, if the overall estimate says that the biotope in question is threatened.

A specialist, who participated in the work but wants to remain anonymous, says that these percentages should not be taken literally. “Out of their larger context, they are very easily misleading,” he says.

Short period of survey creates problems

The most important criteria for threatenedness is the development of the biotope during the past 50 years. This is an astonishingly short period of time, not least because there is plenty of information on forest nature even in the 19th century.

The second most important criteria in based on the future development of the biotope. That, of course, is based on estimates only.

The third most important criteria, the development of the biotope before the period surveyed for the first criteria, is defined in a way which says a lot about the researchers’ mindset: the definition only takes into account the weakening of a biotope.

Yet it is practically certain that several forest biotopes have gained ground since the beginning of the 20th century, due to the fact, for example, that the volume of trees and wood in Finnish forests has grown radically since then.

The study states that the most threatened biotopes in Finnish forests are those found in herb-rich forests. It quotes the development of the total area of herb-rich forests from the early 1920s based on the National Forest Inventories, and says that the area has multiplied several times over. The researchers conclude, however, that the figures are not reliable.

Recovery of nature overlooked

The research fails to capture the possible recovery of biotopes, even if was present. This was also discussed among the researchers.

“Yes, we did discuss this. My opinion is that the methods used in this research do not sufficiently take into account that biotopes are also able to recover,” says the anonymous specialist.

The study clearly acknowledges that herb-rich forests are not threatened mainly by forestry, but by the agricultural use of forest land, though most of this use started already before the Second World War. Mielikäinen points out that for hundreds of years until the early 1950s, Finns had practised slash-and-burn agriculture and the selective cutting of the largest and best trees, so that the forests were very young and anything but dense.

Compared to the 1950s, the area of forests under 40 and over 100 years old has doubled in southern Finland. “Up to those times the farmers constantly harvested stout timber, dry tree crowns and windfall trees from their forests, but all that was stopped many decades ago. This is also why the possibility of biotope recovery should have been taken seriously,” says Professor, Mr. Kari Mielikäinen from the Finnish Forest Research Institute. He has gone through the section of the study dealing with forest biotopes.

The study also gives the impression that forestry has constantly intensified since the 1950s, which is not supported by statistics. “Large areas of forests overdue for management, the increase of broadleaves, the growing interval between thinnings and the increase of old-growth forest area in commercial forests suggest that the situation is actually quite the opposite,” says Mielikäinen.

Definition of quality not available

The definition of quality used in the study to determine the threatenedness of biotopes is important, as the deterioration of quality is the most significant cause of threatenedness.

The amount of decayed wood is given a 40-percent weight in the quality criteria. The arguments for this are well presented, and the actual effect of the amount of decayed wood on the criteria is also described in clear quantitative terms.

The remaining 60 percent is called “other estimate”. The factors included in this part are described – including forest fires, windfalls, harvesting, soil preparation – but no hint is given as to how they affect the criteria. The study only notes that almost all human activity is defined as harmful, while the processes of nature are always defined as beneficial. Again, no reasons for either are given.

On the other hand, the research classifies all forests dominated by broadleaves as threatened, although it is obvious that at least a part of them have appeared as a result of slash-and-burn agriculture and is threatened because of the natural trend of spruce to conquer the space of broadleaves.

The object of study is not the “state” of the biotopes, but their “threatenedness”. By definition, then, the state and development of the biotopes is poor from the outset.

This is shown, for example, in the examination of the extent and quality of forest biotopes in the chapter called “Implementation of evaluation”: the sub-section dealing with extent is called “Decrease in extent” and that on quality, “Deterioration of quality”.

“This looks like politics rather than research. It also is impossible to evaluate the many references to expert estimates, as no sources are cited,” says Mielikäinen.

Hannes Mäntyranta

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