This is one of the 150 kelo research plots that can be found in North Karelia, Kuusamo and the Salamanperä Nature Reserve in Kivijärvi, Central Finland. The study was launched in summer 2022 by setting up the research plots and measuring 3,000 dead pines. Sampling will now begin, and will continue next summer.

“The samples will reveal the tree’s growth history: how the tree died and how any disturbances during its lifetime may have influenced its development into a kelo,” says Aakala.

Aakala teaches his students how to take samples. It’s a meticulous task. The tree must be marked at the place where the sample was taken. The sample must be taken from a place where the wood is hard. If the sample comes out in pieces, they must be stored in the correct order.

Studying a tree’s chemical composition requires a great deal of precision, and the equipment must be extremely clean.

“I compare the chemical composition of wood from kelo trees and other dead pines. Kelos contain chemicals that inhibit the activity of decomposing agents,” says Günther.

Could we facilitate the creation of kelo trees?

The increment borer squeals as it bites into the wood. Although the deadwood lying on the ground appears decayed and is covered with moss, dry rock-hard wood can be found right below the surface. The annual rings in the sample are so dense that it’s difficult to count them with the naked eye. The wood has a pitchy scent. I feel the urge to light a campfire, but we’re in a conservation area. And besides, it seems such a waste to throw a deadwood log on the fire after all we’ve talked about.

By studying a tree’s chemical composition and growth history, we can determine what causes trees to produce chemicals that protect them against decay. Old wood always contains durable heartwood, but is that enough or is some disturbance required to slow the tree’s growth or change its chemical composition in some way?

It’s biologically interesting how the pine itself derives no benefit from being decay-proof after its death.

“It’s just a side effect of what happens during a tree’s life,” says Aakala.

In spite of this, the final phase of the deadwood study will launch long-term field trials to determine whether kelo creation could be promoted on the basis of the data collected during the study.

As long as I don’t have to sit indoors all day

Tuomas Aakala was originally destined to become a forester.

“On the way to a moose hunt, my father sometimes mused that if he could start over, he’d choose to be a forester. So he’d get to do work that wouldn’t just be sitting around indoors all day….”

However, when Aakala was a student, it soon became apparent that modern forestry mostly involves sitting around indoors all day. Today’s foresters rarely spend their time wandering amongst the trees.

It was then that Tuomas began to be drawn to research, and turned his gaze from commercial forests to natural forests.

“I was on an exchange at an agricultural university in Austria, where I took a really interesting course on the dynamics of natural forests.”

After that, Timo Kuuluvainen, an associate professor in forest ecology, invited Tuomas to do his master’s thesis in Canada. When Aakala continued with a doctoral thesis on the dynamics of dead trees, his choice of career was firmly set.

He brainstormed ideas for a deadwood study with another well-known veteran researcher, Harri Vasander. This idea spent several years on the back burner until Kone Foundation granted funding for the project in 2020.

Aakala has also studied natural forests in Lapland and Russia. The original idea had been to search for kelo trees on the other side of Finland’s eastern border. Research plots had been planned in the Kalevalsky National Park in the Russian Republic of Karelia.

But along came the pandemic, which postponed the study’s launch by a year. And then came the war. The changed state of the world meant they had to abandon the idea of fieldwork in Russia and cooperation with Russian scientists. Which is why we’re now in a small conservation area in Lieksa.

Strong language is likewise not uncommon in discussions about Finnish forests. The debate on forest usage has been polarised and contentious for decades. The commercial exploitation of forests is at odds with conservation efforts. There’s also dispute over management methods within the forestry sector itself, and particularly between homogeneous and heterogeneous forest management practices (that is, between clear cutting and continuous-cover forestry).

Aakala thinks that this heated debate stems from the fact that the fate of forests is Finland’s most important conservation issue, and yet the country also has considerable economic interests in forests. Finland has 570,000 forest owners, so issues related to forest usage also affect a significant proportion of the population on a personal level.

“A lot of this debate is pretty useless, because it’s so polarised,” says Aakala.

As a member of a younger generation of researchers, he tries not to pick camps, but that’s not always enough to avoid being labelled.

“As I see it, my role is to provide information that is as factual as possible.”

This is vital, as public debate contains persistent myths about carbon sequestration in forests.

Where can we find carbon sinks and stocks?

One common claim is that young and ‘well-managed’ forest is the best carbon sink. However, research data doesn’t back this up.

In reality, the clearings created by logging are sources of carbon emissions, and sapling stands sequester less carbon than natural forest. Commercial forest only beats natural forest as a carbon sink towards the end of the felling cycle – when it’s cut down again.

Commercial forests also have smaller stocks of carbon.

“In old-growth forests, more carbon is stored in the soil in particular, even though the carbon sink formed by living trees and decaying wood is approaching zero.”

In Northern Finland, climate change has spurred even thousand-year-old primeval forests into vigorous growth and carbon sequestration. These forests are naturally few in number, but as growing conditions become more favourable, they can support more trees.

“Old-growth forest is not withering away, as has been claimed.”

Biodiversity loss, for example, has been the subject of much recent debate; and solutions are currently being sought by comparing commercial and natural forests, and then modifying management recommendations for commercial forests.

Eternal wood from the dawn of history

It’s time for a break. A sturdy piece of fallen deadwood naturally makes for a sturdy seat. And sparks a train of thought. In homogenous forest management, the rotation time may be only a few decades at its shortest. (That is, the time from the establishment of the sapling stand to clear felling.)

In a natural forest, a pine can live to be over 800 years old, then stand as a kelo for the same period, and remain on the ground as deadwood for another few centuries. In other words, there is deadwood in Finland that dates back to the time when a certain Jesus of Nazareth first opened his eyes.

We’re sitting on top of eternity as we munch on our sandwiches and sip our coffee. A log truck speeds along a nearby road, probably towards the mills in Uimaharju. Then silence descends once more.

Although kelo trees are part of Finland’s iconic national imagery, there has been very little research into them. But now they’re finally being studied properly. This is a four-year research project, and the knowledge it produces may also lead to further studies.

Data obtained in Finland may also have broader significance. Pines are the most widely dispersed evergreens in the world. They are found everywhere from the tropics to the taiga, and from the Far East to Alaska, and these other pine species also become kelo trees.

“The results of our research can also tell us how other pine species become kelo trees,” says Aakala.

Although the sampling trio are focusing on ecology during this trip, the team also has expertise in ecosystems, flora and fauna – in everything from insects to fungi and birds to lichens.

The team includes researchers from the Universities of Eastern Finland, Jyväskylä and Helsinki, the Finnish Environment Institute, the ELY Centre, the Finnish Museum of Natural History, and Metsähallitus. Both kelo trees and their study are also being documented by photographic artists Sanni Seppo and Ritva Kovalainen, who have been photographing Finnish forests for decades.

The research plots will be bustling next year, as samples are collected and observations of trees, wood fungus and hole-nesting species are made. The remainder of the four-year project will be spent analysing the samples and observations, and writing the research reports.