Clear-cutting of forests decreases soil organic carbon for decades

Anne Olga Syverhuset

2025-04-04T12:41:00.0000000 2025-04-04T14:46:31.1200000

Photo credit: Anne Sverdrup-Thygeson

Nearly half of all the carbon stored on land is found in forests, as both trees and soil act as powerful carbon sinks.

Forest management approaches affect forests ability to store carbon. A large dataset from the Nordic countries and Canada now shows how clear-cutting impacts the soil’s ability to store carbon over time.

“Our analyses show that in coniferous forests, there is a continuous loss of carbon from the organic soil layer for approximately 30 years following clear-cutting,” says Carl-Fredrik Johannesson, researcher at the Norwegian Institute for Nature Research (NINA) and lead author of a recently published study.

At the lowest point, carbon stocks had decreased by 23 percent in spruce forests and by 14 percent in pine forests. In spruce forests, carbon levels remained at this reduced level for the remainder of the observation period (up to 53 years after clear-cutting), whereas in pine forests, carbon stocks gradually recovered and returned to pre-harvest levels 48 years after clear-cutting.

“We are most certain for the period up to 40 years after clear-cutting. Beyond this, we have less data, and uncertainty increases,” Johannesson points out. As suggested in previous studies, the new findings indicate that areas with higher initial carbon stocks also face a greater risk of carbon loss.

“In this context, it is important to note that we have not been able to examine areas where the organic soil layer exceeds 40 cm in thickness—that is, the most carbon-rich sites,” says Johannesson.

Extensive network collaboration

This is the first time that soil data from national forest inventories in Norway, Sweden, Denmark, Finland, and Canada have been compiled and harmonized to account for methodological differences.

“The strength of this study lies in the large, integrated dataset. It has enabled us to identify long-term carbon trends following clear-cutting,” says Johannesson.

There has previously been considerable uncertainty regarding what happens to soil carbon following logging, and this study therefore represents an important contribution to advancing knowledge in this field.

 “Clear-cutting leads to long-term loss of soil carbon in the organic layer, and the losses are greatest in the most carbon-rich forests—such as high-productivity spruce forests, which are also particularly important for biodiversity. Extensive clear-cutting makes it even more challenging to meet Norway’s climate targets for 2030 and 2050,” says NINA researcher Jenni Nordén, who leads the ForBioFunCtioN project, to which the recently published soil carbon study is linked.

“Soil carbon loss following logging is accounted for in the methodology used in Norway’s greenhouse gas inventory for forests, but to achieve more realistic and less uncertain estimates, additional data from Norwegian forests are needed,” says Nordén.

The work was carried out through the researcher network NorForSoil, funded by Nordic Forest Research and coordinated by Lise Dalsgaard at Norwegian Institute of Bioeconomy Research (NIBIO); the research project ForBioFunCtioN, funded by the Research Council of Norway; and the BIOCARBON project at NINA, led by Zander Venter. NINA’s collaborators in the study included NIBIO, the Swedish University of Agricultural Sciences, the University of Copenhagen, the Natural Resources Institute Finland (Luke), and the Canadian Forest Service.

Contact: Carl-Fredrik Johannesson

Read article here: Decadal Decline in Forest Floor Soil Organic Carbon after Clear-Cutting in Nordic and Canadian Forests

Less Outdoor Recreation in Forests After Clear-Cutting – Especially Near Cities

Anne Olga Syverhuset

2025-03-05T08:21:00.0000000 2025-03-25T14:28:10.4770000

With high timber prices in recent years, many people have seen their local forests harvested or new forest roads cutting through familiar hiking areas. Visual studies have shown that people prefer forest landscapes without obvious interventions, especially areas without clear-cutting. But how does this aesthetic preference affect people’s actual use of forests for recreation and physical activity?

Researchers from the Norwegian Institute for Nature Research (NINA) analyzed 2.7 million fitness activities along forest trails recorded by the Strava app, before and after clear-cutting, to determine whether clear-cutting impacts how people use nature.

“There are more than 70 published scientific papers in the Nordic region showing that clear-cuts are the least preferred type of forest. This study is one of the few that examines how new clear-cuts actually affect recreational use,” says NINA researcher Vegard Gundersen, who has studied the topic for many years.

And clear-cuts do have an effect:

“We found that after logging, there was a 3.7% decrease in the number of hikers in the affected areas. Overall, we estimate that clear-cutting displaces about 1.5 million recreational activities annually, including hiking, cycling, and skiing. The clearest effect is seen near urban areas,” says NINA researcher Zander Venter, who analyzed the Strava data.

More Skiing After Clear-Cutting

Although people prefer old-growth forests, other factors—such as accessibility and infrastructure—can play an equally important role in usage. Previous research suggests that the construction of forest roads and open areas after logging can in some cases improve access and thereby promote recreational activity. As a result, the effect of clear-cutting varies greatly between different types of activities.

“So while the overall effect on recreational activity is negative, we found an increase in cross-country skiing after clear-cutting. The logged areas have a different visual effect in winter—they provide open spaces with light, and the snow covers the traces of logging. Even though we see a positive effect on skiing, skiing makes up a smaller portion of overall outdoor activities”, Gundersen explains.

Clear-Cutting Can Have Significant Consequences for the Recreational Value of Forests

In other European countries, natural capital accounting shows that outdoor recreation is the ecosystem service with the greatest socioeconomic value. The value of outdoor recreation is substantial because seemingly small values per user add up across large numbers of people, especially in urban-proximate recreational areas. Even small percentage impacts on outdoor recreation due to open clear-cuts in urban forests accumulate over the years. This leads to an overall loss of value that can be significant compared to the value of the harvested timber.

At the same time, the researchers’ estimates of recreational value loss are conservative, as they do not include potential losses from other activities such as mushroom and berry picking, hiking, and camping off the trail network. The effects on biodiversity from clear-cutting, or on public health due to reduced nature-based activity, were also not included in the study.

“Still, we document substantial socioeconomic losses for outdoor recreation due to clear-cutting in Østmarka, Nordmarka, and other urban forests in Norway,” says NINA researcher David Barton, who works on the economic valuation of ecosystem services.

A regulation on forest management and operations in Oslo allows the municipality to deny logging when it poses a ‘significant disadvantage for outdoor recreation.’

“What constitutes ‘significant’ in politics and economics is relative. The question of how large the losses of ecosystem services, biodiversity, and public health need to be before they are considered ‘significant’ compared to the value of timber from clear-cutting is a political one. We need to work together to find out how forestry can be locally adapted so that it is not ‘significantly’ negative,” Barton concludes.

Read the full article: Impacts of forest clear-cutting on recreational activity: Evidence from crowdsourced mobility data

Contact: Vegard Gundersen