Forests continue to be a carbon sink, but the sink has diminished, and is no longer large enough to fully compensate emissions from agriculture and other land use. Decrease in carbon sinks has at least few major causes:
- Wood harvest level in Finland has increased from 2020 to 2021.
- Forest growth has slowed down
- Carbon sink calculation method has changed: according to researchers, carbon sink figures from earlier years are not comparable with 2021 figures.
Public debate in Finland is simplifying the issue, and increased wood harvests are being blamed, even though they are only part of the truth. Harvest levels in Finland fluctuate from year to year (public statistics by Natural Resources Institute, million cubic meters):
- 2017: 72,4 Mm3
- 2018: 78,2 Mm3
- 2019: 72,9 Mm3
- 2020: 68,9 Mm3
- 2021: 76,4 Mm3.
Sustainable harvest levels are defined with the help of forest growth. According to latest national forest inventory in Finland, forest growth was 103,5 Mm3 annually during 2014-2020, which is significantly higher than the harvest levels during that period. Forest growth had slowed down from the previous national forest inventory by 4 Mm3. According to researchers from Natural Resources Institute, the growth has slowed down especially in pine forests in northern Finland, while in Southern Finland the growth has remained the same.
Forest age structure is currently dominated with class of 60–80-year-old trees, which grow slower compared to younger age classes. Pine has had three weak growing seasons during 2018-2020 due to drought and record high seed cone production. Forest growth has slowed down also in Sweden and in Norway.
In addition, the researchers have observed that pine forests are often being thinned only once during their lifetime instead of two or more thinning, which means that more wood is removed from the forest at once, but the growth of the forest during its whole lifecycle is poorer. Instead of one heavy thinning, it would be better to carry out several thinning and remove smaller amount of wood from the forest at a time to enhance forest growth.
According to Natural Resources Institute, we should not compare the carbon sink calculations from previous years to 2021 figures since the calculation method is different. Researchers brought this up in press releases in May, but the topic was soon forgotten from public discussion.
Shrinking carbon sinks provoke intense objections, because carbon neutrality targets of Finland are strongly tied to certain carbon sink figures, which compensate emissions from agriculture and other sectors such as energy. Forest growth and the use of renewable raw materials such as wood need to be increased to replace the fossil raw materials. This calls for active, timely forest management, such as thinning at certain interval according to recommendations and using fertilization. Our target must be increasing the forest growth, not giving up the forest harvests. Forest industry operates in global markets, and multiple studies have demonstrated that decreasing wood harvest in one country or region would only transfer the harvest as carbon leak to another location, possibly into conditions with weaker monitoring and lower sustainability standards.
Active sustainable forest management has doubled the forest growth in Finland since 1960’s and created remarkable carbon storage and sink. Regardless the level of our carbon sinks, Finnish society must focus on actions to cut down carbon emissions.
Studies:
Läckageeffekter från skog och skogsbruk