Federal Forest Inventory: Forest has lost its function as a carbon sink

The latest National Forest Inventory for Germany, which is published every ten years, was published on October 8. The basic message it contains is alarming and worrying: the forest has lost its ability to store carbon and instead releases CO2 into the atmosphere. A sink has become a source of carbon within ten years. This means that the predominant loss due to storms, drought and beetle infestation is greater than the increase in living biomass. Since 2017, the carbon stock in the forest has decreased by 41.5 million tons. The National Forest Inventory is the most comprehensive survey on the condition and development of forests in Germany.

Every ten years, the Thünen Institute records the condition of German forests on behalf of the Federal Ministry of Agriculture by collecting and analyzing a wide range of data.

These include

• the size of the forest area
• the age of the trees
• the composition of the tree species
• The state of the forest
• The extent and type of cultivation - whether intensive or sustainable

"A strong forest means climate protection for us - that's where we have to go."

Cem Özdemir, Federal Minister of Food and Agriculture

Key results at a glance:

• Carbon storage & carbon footprint: loss of 41.5 million tons of carbon since 2017. Forests have become a source of carbon for the first time in decades. This underlines the urgent need for measures to adapt and restore forests in order to strengthen their role as climate protectors in the long term.

• Forest area: 11.5 million hectares (+15,000 hectares since 2012). The forest area remains stable, which is a positive sign for the preservation of this important resource as the basis for its diverse ecosystem services, especially in the context of land sealing by settlements and infrastructure in a densely populated and heavily industrialized country like Germany.

• Calamity areas: 2 million hectares of forest are affected by calamities, i.e. damage caused by natural forces. Calamities such as drought, storms and bark beetle infestation can affect individual trees, groups of trees or entire stands. On 34 percent of the calamity areas, there was no forestry use, on 20 percent the dead trees were used over a wide area. The high number of calamity areas is alarming and highlights the need for urgent measures to strengthen the resilience of forests against pests and diseases.

• Wood stocks: There are 3.6 billion cubic meters of wood in our forests. By 2017, the timber stock had risen to 3.8 billion cubic meters. Due to storms, drought and the subsequent calamities as well as a 16% decline in growth, the timber stock fell to the 2012 level.

• Deadwood percentage: The 32 percent increase in deadwood percentage is both a positive and a negative sign. Deadwood is important for biodiversity and provides a habitat for many species. However, the increase is mainly due to climate damage, which highlights the vulnerability of forests to extreme weather events.

• Proportion of deciduous and coniferous trees: 48 percent deciduous trees and 52 percent conifers. The increase in the proportion of deciduous trees is encouraging, as it increases resilience to the changing climate.

• Mixed forests: 79 percent of forests are mixed forests (+3 percent since 2012). The increase in the proportion of mixed forests is a positive signal for biodiversity and the resilience of forests. Mixed forests offer greater resistance to pests and diseases as well as better adaptability to climate change. This diversity helps to reduce the risk of large-scale damage caused by climate factors.

Forest fails as a helper in climate protection

The German Climate Protection Act assigns an important role to forests, which, together with peatlands, are to absorb an average of at least 25 million tons of carbon dioxide per year from 2027 to 2030. This is intended to offset emissions in other areas such as agriculture and industry. By 2045, the target is even 40 million tons.

This plan is not working: Our forests are no longer a storehouse of greenhouse gases, but have become a source of carbon, especially since the drought year of 2017 due to the climate crisis, primarily through the loss of living biomass - the wood supply serves as an indicator of this. According to the science magazine "Spektrum", the massive dieback of spruce and pine monocultures in recent years is one of the causes of this, as coniferous forests have suffered particularly in the recent drought and storm years since 2017.

"The question is rather whether the negative trend of recent years can still be halted."

Pierre Ibisch, forest expert

The forest expert at the Eberswalde University for Sustainable Development, Pierre Ibisch, even assumes that the forests' carbon footprint is actually even worse because the data from the federal inventory dates back to 2022 and the death of spruce and pine plantations has continued since then. In addition, in his opinion, the inventory did not include greenhouse gas emissions, which are produced in large quantities when areas with dead trees are cleared, for example after a bark beetle infestation. This also releases carbon previously bound in the soil into the atmosphere.

This is confirmed by calculations by the Thünen Institute, according to which only a low net sequestration of 0.2 million tons of_{CO2 equivalent} is expected between 2027 and 2030. The experts are convinced that the "target of a net sequestration of 25 million tons_{of CO2 equivalents} will be clearly missed".

"The fact that the conversion from coniferous monocultures to climate-stable deciduous forests was not tackled early and consistently is now taking its toll."

WWF forest expert Susanne Winter

In her opinion, the "25 million ton target" can only be achieved with a reform of forestry that is consistently geared towards protecting and conserving the forest. This would require a drastic reduction in the total logging volume, especially in old deciduous forests, the "guarantors for the storage of huge amounts of carbon".

Based on data from the German National Forest Inventory, the forest scientist has calculated that more than 30 percent of annual logging would have to be cut in the coming years in order for forests to grow enough to achieve the climate targets by 2030.

What is the situation of the forest in Austria in this respect? Since we have a similar starting position, have had to contend with similar climatic challenges and also similar calamities, the balance sheet should not look much different.

The path we have taken towards stable, species-rich and structurally diverse forests must be consistently pursued. Silvicultural action must adapt to the new climatic challenges. Climate change not only threatens the vitality of our forests, but also their function as the economic basis of many businesses.

Links

The results of the National Forest Inventory can be found on the BMEL website and at Federal Forest Inventory.

You can see how the National Forest Inventory is carried out in this video of the FNR