Europe's Forests Maxing Out in Terms of Carbon Absorption

Europe's forests appear to be hitting their limit in terms of absorption of atmospheric carbon dioxide, a study published in the journal Nature Climate Change reports.

After centuries of stock decline and deforestation, the continent's forests began to recover starting in the 1950s. However, some 60 years later, the report warns of early signs of absorption saturation as a result of, according to the BBC, "declining volume of trees, deforestation and the impact of natural disturbances."

The evidence for this can be broken down into three main points, the researchers found, the first of which is a decrease in the stem volume increment rate of individual trees. The second is the intensification of land use, leading to deforestation, and the third includes "natural disturbances," such as wildfires, which are on the rise "and, as a consequence, so are the emissions of CO2."

According to co-author Gert-Jan Nabuurs from Wageningen University Research Center, what this all adds up to is not only a stagnation in the ability of Europe's forests to act as a carbon sink, but a slight decline even.

A carbon sink includes anything that absorbs more carbon than it releases, thus reducing the overall amount found in the atmosphere. And while carbon is a necessary ingredient for life, human activity since the Industrial Revolution has resulted in a sharp increase in the amount released into the atmosphere that, until then, had remained locked in the earth.

Meanwhile, urbanization and deforestation has led to a similarly significant decline in the amount of vegetation available to re-absorb this carbon. Thus, when the situation becomes such that absorption is no longer able to keep up with its release, "saturation" occurs.

One of the reasons Europe's forests appear to be reaching this point despite an increase in trees both during the beginning of the 20th century and after World War II is due to the fact that many of those trees are now reaching maturation and, as such, slowing down in terms of growth.

"So you have large areas of old forest and even if you add these relatively small areas of new forest, this does not compensate for the loss of growth rate in the old forests," Nabuurs explained.

To combat this problem, the researcher argues that while older forests, in many cases, represent valuable habitats, "in other regions, maybe it is time to concentrate more on continuous wood production and rejuvenate forests again, so then you can have growing forests and a continuous flow of wood products."

In doing so, he says, countries would be addressing two important issues: the need for wood in regards to manufacturing and production, and the preservation of a carbon sink in the form of young, growing forests.