In the once verdant Harz mountains of northern Germany, a grim sight has emerged. Thousands of skeletal tree trunks, the remnants of a once-thriving spruce forest, stand as a testament to the devastating impact of a bark beetle outbreak that has ravaged the region since 2018. This ecological crisis, exacerbated by successive droughts and heatwaves, has sparked a reckoning within the German forestry industry, leading to the exploration of a more diverse and resilient approach to forest management.
The ferocity of the bark beetle infestation has made it clear that simply replacing the dead spruce with saplings of the same species would be a recipe for disaster. Instead, foresters have turned to a new strategy, planting pockets of beech, fir, and sycamore around the surviving spruce trees. The goal is to create a more diverse landscape that can better withstand the challenges posed by a changing climate.
“You cannot force the forest to grow – we cannot command how much their contribution should be towards our climate targets,” explains Mathias Aßmann, a spokesperson for the regional forestry company responsible for this part of the Harz range. The rapid loss of trees has raised scrutiny about how nature can be leveraged to meet climate commitments in a warming world, as vast dieback events become increasingly common across Europe.
Research has shown that biodiversity can be a crucial defense against drought-induced tree mortality. A 2018 study in Nature found that tree diversity was the best protection against drought die-offs, while research published in PNAS last year revealed that species richness safeguarded tree growth during prolonged seasons of drought. Monocultures, on the other hand, are far more vulnerable not only to drought but also to outbreaks of disease, bark beetles, and wildfires – all of which are eating away at the world’s carbon sinks.
The Harz mountain range has weathered major challenges before, from mining-related deforestation to the ravages of acid rain. But Aßmann acknowledges that a new approach will be needed to navigate the intense global heating that is now unfolding. “Even if there are pests like bark beetles on spruce, it doesn’t matter because there are young trees beneath it. They can grow, and the forest as a whole won’t disappear because there’s only one spruce next to a Douglas fir, next to the beech and so on,” he says.
These healthier, more diverse forests offer hope not only for the land itself but also for the people who have dedicated their lives to its stewardship. “Many people worked in these forests for 40 years, and in just three years, all their work is gone: cut down and put in a truck. It’s very hard for them. So this place is good for their soul. It’s a good goal for them to work towards,” Aßmann reflects.
As the global community grapples with the consequences of a warming planet, the Harz forest’s journey towards resilience serves as a powerful example of how a shift towards more biodiverse cultivation could hold the key to safeguarding the world’s precious carbon sinks.
