Initiative "Der Wald ruft" 

Our forests have to adapt to the acute and rapid climate changes. However, complex ecosystems like forests need many forest generations for such an adaptation, which can take 100 to 200 years or even longer. With their long generational cycles, forest ecosystems are therefore under particular pressure.

Spruces are shallow-rooted and therefore vulnerable to storms. They also need a lot of water to grow. At the same time, water is needed for the production of resin, for example to repel bark beetles. After the storm Frederike and the dry summers from 2018 to 2020, the weakened spruces became more susceptible to bark beetle infestations. The main problem here is the lack of rainfall during the growing season. In addition, many spruce forests still grow outside their natural range today. The overly warm locations or poorly rooted soils increase the vulnerability of these spruce forests.

Many of the pure spruce forests were planted directly after the Second World War. At that time, they were the only fast-growing tree species available in large quantities as seeds, from which plants for reforestation could be grown. It was also impossible to plant more demanding tree species on the large open areas with their extreme climatic conditions. Spruce wood was urgently needed for reconstruction and economic growth.

The foresters have been “restructuring” the pure conifer forests for several decades now. They rely on site-adapted and diverse deciduous and conifer tree species that can better cope with climate change. However, forest restructuring and tree growth take time, so developments only become visible after a while.

National parks protect natural processes. By allowing phases of decay and collapse, they create valuable habitats that have otherwise become rare. That’s why the wood in the area of the Harz National Park largely remains in the forest. Once the bark has fallen off, there are no bark beetles left in the deadwood. The young beetles have long since flown away and found other host trees. Deadwood provides an important habitat for fungi, insects, birds, and bats.
 

Deadwood is also left in managed forests for ecological reasons. However, standing deadwood can pose a danger to people during reforestation and later forest maintenance. For workplace safety reasons, it has to be removed from many areas.

Since future developments are uncertain, there is no general answer to this question.

In the national park, nature is only interfered with in a few areas. This allows the forest here to turn back into a wild natural forest.
 

In the managed forests, the forest is actively changed through what is known as forest conversion. Pure coniferous forests are transformed into more stable mixed forests with trees of different ages. This is done by planting and by natural regeneration such as seed fall and sowing. The diversity of tree species in the forest is meant to promote its ability to adapt to the future climate.

In the high altitudes of the Harz Mountains, spruce trees are naturally native and will therefore continue to be the main tree species alongside rowan. At lower altitudes, mainly deciduous trees such as beech, sycamore, rowan, willow, ash, and oak will grow more frequently again.

On one hand, forests are threatened by climate change, but on the other, they also reduce the CO2 content in the air. Trees and forests absorb climate-damaging CO2 from the atmosphere as they grow. The wood of trees and the soil store large amounts of CO2, thus making a positive contribution to the climate balance.

Both the Harz National Park, the state forestry enterprises and private forest owners take their duties to ensure traffic safety very seriously and work on maintaining the forest trail networks, managing forest care, timber harvesting and meeting the needs of forest visitors.
 

Nevertheless, for your own safety, please follow the rules of conduct of the forest etiquette before and during your visit to the forest, and observe any possible closures & diversions.

Bark beetles are a natural part of the forest ecosystem and have always been present in forests. They infest sick, dying or fallen trees and then emit a scent that attracts other bark beetles. Dry years favour reproduction, allowing the bark beetles to spread particularly strongly in the weakened spruces.

You can recognise a bark beetle infestation on a tree by sawdust, fallen green needles, discoloured crowns, peeling bark or traces of woodpeckers searching for larvae under the bark.

A female bark beetle, together with her offspring and their descendants, can produce hundreds of thousands of offspring in just one year. In a dry and warm year, up to three generations of bark beetles can develop. However, a tree’s defence mechanisms already fail once about 200 beetles have infested it. After overwintering, the beetles start flying in spring when air temperatures reach 16 degrees.

The brood pattern of the large eight-toothed spruce bark beetle resembles an open book – which is why the beetle is also called the book printer. The brood pattern of the smaller copper engraver, on the other hand, is star-shaped and its name refers to copper engravings.

From spring onwards, traps and chemical attractants can be used to catch the beetles in commercial forests in order to limit the population from the start. However, such measures only help to a limited extent in the case of a massive infestation.