Tomorrow‘s Forests?

I still recall an Umweltgespräch (environmental discussion) in Freiburg that addressed droughts and heavy rainfall. The predictions made by the speaker six years ago have essentially come true.

That's why I was fascinated when I read about two evening lectures in the series Umweltgespräche, focusing on the forests of tomorrow.

German forests have always fascinated me. In 2015, I blogged about the severe damage to forests in Germany's Mittelgebirge (medium high mountain regions), such as the Harz Mountains.

In 2020, I revisited the topic of Waldsterben. The beginning of the coronavirus pandemic was a challenging year for people, but particularly devastating for German forests.

Finally, in 2023, I learned that not only do forests surrounding a city mitigate the local climate, but individual trees within the city can also reduce heat spots.

That's why I was excited about the two lectures, whose content was contrasting and therefore made for a fascinating evening. 

Prof. Jürgen Bauhus, Chair of Silviculture at the University of Freiburg, played the skeptic and demonstrated in his lecture, "Wald im Wandel, Wandel in den Köpfen (Forest in Transition, Transition in Minds)," that the topic of forests is much more complex and multifaceted than I had previously assumed.

In contrast, Ms. Nicole Schmalfuß, head of the Freiburg Municipal Forestry Office, took a pragmatic and practical approach to the subject in her presentation "Stadt - Wald - Vielfalt (City - Forest - Diversity)."

Freiburg's Environmental Mayor, Christine Buchheit, welcomed those present and pointed out that tonight's lectures would be attended not only by Freiburg citizens, but also by participants in a specialist workshop entitled "Wald neu denken (Rethinking the Forest)" taking place in Freiburg this week.

The evening's moderator, Prof. Heiner Schanz (left), introduced Prof. Bauhus as the first speaker. The latter emphasized the balancing act he had to perform to satisfy both the citizens and the experts present with his lecture.

He then complained about the small projection screen, as the hall was overflowing with people. Many listeners had to stand in the back, where they could probably only see splashes of color. Red Baron had arrived early, managed to get a seat in the third row, and was just able to read the slides. Nevertheless, the quality of my shots of the screen you will see in the following leaves much to be desired.

Here are a few points that stood out to me and were new to me.

Prof. Bauhus presented the research approach of the Cluster of Excellence on Future Forests in Freiburg.

Feedback on risks and potential adaptation options for forests, as well as their impacts on future forest decision-making, is incorporated into forest research. These two inputs can be used to develop transformation pathways for future socio-ecological forest systems.

The drivers of change include extreme events, disturbances, interactions, targeted environmental changes, system shifts, tipping points, and societal changes. Their predictability is limited. Here are examples:

According to the German Climate Protection Act, greenhouse gas emissions (essentially carbon dioxide and methane) in the land-use ecosystem are to be reduced by 25 million tons by 2030. However, after three consecutive dry summers between 2018 and 2020, so many trees died in the low mountain ranges that the balance was ruined, and only a saving of around 1 million tons of greenhouse gases is expected by 2030.

The planting of late-flowering black cherry trees (Prunus serotina) in the Netherlands was a complete misjudgement. The species forms dense stands and suppresses the regeneration of native trees (e.g., oak or beech). Prunus serotina's leaf litter changes the soil chemistry and hinders the growth of other plants. Between 1965 and 2018, this American import spread so rapidly that to date €500 million has been spent on combating it. 

Therefore, plans and decisions on climate protection can only be made against a backdrop of great uncertainty. In the above graphic, the lower blue ecological system state will be reached when no action is taken. Although planned remedy activities point in the right direction, they are not very targeted.

Changes in forests also require changes in society, or environmental changes generally go hand in hand with social changes.

On the one hand, forests have the capacity to provide a range of ecosystem services. On the other hand, society relies on the services this ecosystem provides. The resilience of these socio-economic factors is crucial, so risks must be mitigated through adaptation and overcome through transformations.

Results of studies show that locally adapted tree species are not always the best choice for reducing greenhouse gas emissions. However, changing tree species alone does not preserve the carbon sink properties of forests either. The best approach is flexible regeneration of adapted tree species, coupled with controlled changes in their composition. A suitable selection will maintain the CO₂ balance and can even improve it.

The future utilization potential of trees can be derived from forest utilization between 2012 and 2022. This results in an 18% decrease for spruce, a 43% increase for pine, a 160% increase for oak, and a 178% increase for beech in the years up to 2037.

The second speaker of the evening was the lively Ms. Schmalfuß.

She showed that forests cover 42% of the 6,509 hectares of the city of Freiburg. The small image illustrates the drought index in Germany for the year 2024. It shows that the moisture situation in the far southwest of Germany is quite different from that in the east (indicated by the brown areas).

Here are the predictions of future droughts made in 2019.

Freiburg boasts a diverse range of forests, from mossy to mountainous, and everything in between.

Ms. Schmalfuß presented the Freiburg Forest Convention of 2020. The city forest is preserved and managed in a way that ensures and promotes all four forest functions - protection, utilization, recreation, and climate mitigation - equally.

The objectives are:

1. Permanent preservation of the city forest
2. Preservation and promotion of biodiversity and other protective functions
3. Stability through diversity
4. Sustainable timber production
5. Increased use of timber in construction (buried  CO₂)

6. Preservation and promotion of the climate protection performance of the city forest
7. Preservation and further development of the recreational function of the city forest
8. Forest and environmental education in the city forest
9. The city forest as a workplace: occupational safety and training quality
10. The Freiburg city forest as an object of research, teaching, and study

The city forest (light green) is primarily a multifunctional commercial forest. Blue areas are forests with a prominent recreational function. Purple areas are extensive and maintenance areas, while dark red areas denote decommissioned forest areas.

The equal importance of the various functions does not mean that the same goals should be pursued everywhere since the diversity of forests requires differentiation.

Forests with a long history of forestry have great potential for biotope protection. Forests with high growth rates have great potential for climate protection. Forests with high-quality wood have significant potential for commercial use, while those located near cities have substantial potential for recreational purposes.

The concepts and instruments for implementing the Freiburg Forest Convention are:

1. Systematic management control, i.e., forest management with interim reviews and annual planning
2. FSC (Forest Stewardship Council) certification
3. Near-natural forestry and the forest development type guideline
4. Long-term adaptation to climate change
5. Old and dead wood concept
6. Biodiversity action plan
7. Integration of management planning in Natura 2000 areas*
8. Regulated hunting
9. Information and guidance for forest visitors through attractive infrastructure offerings and a forest recreation map
10. Forest education in the city forest as a contribution to education for sustainable development and inclusion - offerings by the Forestry Office and Waldhaus Freiburg

*European animal and plant species protected areas

The slide on the planned management of forest facility renewal within the 10-year plan of the updated Freiburg Forest Convention was simply not legible.

Tomorrow's forests? Ms. Schmalfuß ended her lecture with an optimistic outlook:

Still forests tomorrow!

**