Researchers at Linnaeus University and Sweden’s Agricultural University have recently published the study From source to sink – recovery of the carbon balance in young forests in Agricultural and Forest Meteorology about how long it takes for a young forest to go from being a carbon source to become a carbon sink. The results shows that regeneration felling areas become carbon sinks in a much shorter time than previously thought. Managed forests in Sweden are simply carbon sinks during a very large part of their long cycle from seedling to finished log.
The study had five test sites where measurements were made, four in south of Sweden and one in central Sweden. The soil conditions must have been the same at all locations, but due to a colder climate, the site in central Sweden was less productive. The researchers also reported differences in the composition of the tree species and the management between the different locations.
”The average for all the regeneration felling areas was between eight and thirteen years
In one of the regeneration felling areas, it only took eight years before the new forest began to capture more carbon dioxide than the land gave off. The average for all the areas was between eight and thirteen years. In the regeneration felling area that had the lowest carbon dioxide emissions and the shortest recovery time, many of the tree stumps, trunks and pits were removed after felling, which led to the total net storage of carbon becoming positive already eleven years after the rejuvenation felling. The researchers believe that this shows that production stands in southern Sweden are carbon sources during a relatively small part of the orbital period. This period can be further shortened by increasing productivity or reducing the amount of root left behind after felling.
In a growing forest that has reached a certain age, the trees no longer grow as fast, and the forest therefore does not bind as much carbon dioxide. Carbon dioxide is also emitted from dead trees, vegetation on the ground and slowly decaying root systems. It is not unexpected that the researchers found that the regeneration felling area where fewer stumps, trunks and roots were left behind emitted less carbon dioxide, but it’s important that biodiversity is also taken into account. The more stumps, trunks and roots that are left behind after a regeneration felling, the better for biodiversity. On the other hand, increased growth in the forest can contribute to an increased sequestration of carbon dioxide, as well as the utilization of more residual products in the forest industry.
”Increased growth in the forest can contribute to an increased sequestration of carbon dioxide
Regardless of whether there is forest on a piece of land, the land is constantly releasing carbon dioxide. But with forest on the ground, the trees bind the carbon dioxide. The forest plays an important role in solving the climate issue. However, not only as a carbon sink, but also as a renewable raw material for products that often replace fossil raw materials.
Please watch our film which explains the process the forest goes through from carbon source to carbon sink.