A clear-cutting site in Kontila, Mikkeli, in August 2021. Natural Resources Institute Finland (Luke) on Wednesday confirmed that rising felling volumes are a key reason behind the shrinking of carbon sinks, a development that threatens to derail the climate goals of the Finnish government. (Roni Rekomaa – Lehtikuva)


A REPORT by Natural Resources Institute Finland (Luke) has confirmed that the land use sector has turned from a carbon sink into a source of emissions in part because of rising felling volumes, states Minister of the Environment and Climate Change Maria Ohisalo (Greens).

“This was naturally expected based on the preliminary data,” she commented after the ministerial group on climate and energy affairs had examined the report on Wednesday.

“We had a positive discussion about the report and will have to continue our work. The information is tremendously alarming, and the government shares an understanding that more has to be done.”

Luke on Wednesday published its report of the reasons behind the unprecedented change in the land use, land-use change and forestry sector. The primary reason, it concluded, is that the carbon sink of forests has more than halved as a result of intensifying felling and slowing growth.

While felling has intensified since the 1990s, forests grew at a faster clip, sequestering carbon dioxide from the atmosphere to fuel their growth, until their growth began to slow down in 2014. Last year, the total drain from forests – that is, the amount of roundwood removed and left in forests as felling residue – was almost 92 million cubic metres, an increase of over 25 per cent from a couple of decades ago.

The slowing growth is attributable to a handful of factors, mostly related to the biology of pines, which account for almost half of trees in Finland.

Although the growth rate of pines varies depending on the latitude, the growth is the fastest at 21–40 years and second fastest at 41–60 years. In Northern Finland, 61–80-year-old pine forests occupy the largest land area.

The age structure of forests is expected to inhibit forest growth until the 2030s. A rebound to rates higher than the present is not expected until the 2040s.

Luke estimated, though, that the age structure of forests explains only roughly a fifth of the decline in growth.

The growth has also slowed down due to lack of soil moisture – particularly during the dry summers of 2018, 2019 and 2020. The amount of soil moisture depends on, for example, when snow melts.

Another reason is reproduction: In 2020 in Northern Finland, the cone yield was the fifth highest since 1979. Previous studies have shown that the volume growth of pines decreases typically by 10–20 per cent in years with high cone yield, as trees exert their energy on producing cones rather than growing.

The fourth reason for the slowing growth of pine forests is aggressive thinning, according to Luke. Although thinning can provide an individual tree more space, light and nutrients to grow, it has a negative impact on the growth of the forest as a whole. Luke found that both the thinning area and thinning intensity have increased in the 2000s: while a few decades ago thinning entailed felling roughly 30 per cent of trees, the percentage stood at about 40 per cent in 2021.

Qualitative analyses of thinning also reveal that nearly 25 per cent of forests have been thinned too aggressively in recent years, compared to less than 10 per cent in the early 2000s, wrote Helsingin Sanomat.

“My assumption is that thinning doesn’t explain what happened last year; other reasons were identified for that,” Kari Korhonen, a research director at Luke, stated to the newspaper. “But dry summers and high cone yields occur only every once in a while. Thinning has developed negatively, and it has done so for some time. It means this is a factor that has a long-term impact on growth.”

Luke viewed that Finland is presently set to fall 50–80 million tonnes of carbon dioxide short of the carbon-sink target imposed on it by the EU for 2021–2025. A failure to meet the target would oblige the country to either buy removal units from member states that met their national target or reduce emissions in other sectors of the economy, such as transport.

Ohisalo on Wednesday told YLE that the report indicates that forest management is not on a sustainable foundation in Finland.

“The situation is alarming from many standpoints. When trees grow slower, it’s alarming also for the forest industry. Our forest management isn’t on a sustainable foundation at this moment. We’re weighing up various measures with different stakeholders,” she commented to the public broadcaster.

“Felling hit a record-high level last year. Reducing felling has to clearly be part of this effort to foster carbon sinks.”

She also conceded that the development could inflict significant costs on the country. “These are still being calculated at the EU, but it’s true that we have certain obligations and that there’ll be some kind of price tag on them.”

Minister of Agriculture and Forestry Antti Kurvinen (Centre) similarly described the findings of the report as concerning but suggested that they may not necessitate a decrease in felling – but possibly felling at earlier stages and in greater volumes.

“We all share a concern for the well-being of forests. It’s a concern for nature conservation, the forest industry and the administration. You can’t say that limiting felling alone is some kind of answer,” he argued according to YLE. “We need more felling in some respects because we aren’t thinning young forests at an early-enough stage, and this is causing problems.”

“We have to dedicate all our resources to boosting the growth of forests. We’ll need to fertilise, to fell more, but we have to do that at the right time.”

Aleksi Teivainen – HT