In the last three years, Germany, and especially North Rhine-Westphalia,
has experienced strong and persistent droughts.
Last year, the State Office for Nature, Environment and Consumer Protection (LANUV) found the lowest groundwater level ever measured at 720 of 2,000 measuring points in the region.
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Due to the drought, but also to the effects of pollutants, the forest, especially the spruce, is suffering.
In Germany the spruce covers 30% of the total forest area, and is therefore the most common tree.
Spruce wood is an important raw material, it is used as construction material, furniture wood
and also for paper production.
The forestry industry in NRW provides about 150,000 jobs.
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In Europe there are about 150 species of bark beetles.
They infest weakened or diseased trees, thus ensuring that there is enough dead wood in the forest.
They are uselful insects.
The most common species are the "European spruce bark beetle" (Pityogenes chalcographus),
and the "Six-toothed spruce bark beetle" (Ips typographus)
- of dark brown color, and slightly smaller than a grain of rice.
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When a bark beetle visits a tree, it drills a hole in the bark and builds a breeding chamber
in the living intermediate skin between bark and wood - the cambium.
However, it can only do this in weakened or diseased trees that do not have enough resin to defend themselves. Healthy spruces use their resin to glue the chamber and the beetle together,
thus solving the problem.
But if the beetle is successful, it produces an olfactory substance to attract other conspecifics.
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A healthy tree can repel up to 200 bark beetles.
A female beetle can lay 30,000 eggs per year.
Too many beetles or too little resin interrupt the sap flow in the tree trunk,
destroying the nutrient pipes, and the tree dies.
No water - not enough resin.
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Bark beetles have multiplied explosively in recent years.
They infest larger and larger areas, leaving behind clear cuttings and devastation.
Forest owners and forest enterprises do not succeed in removing the "beetle wood" quickly enough.
In 2019 alone, the infested forest areas in NRW increased by a third -
in total, the damage was as large as 1.5 times the city of Cologne (680 square kilometers).
In Germany, an area of the size of the Saarland is affected.
The damaged wood can only be used for animal litter, chipboard or pallets.
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By the end of 2021 - according to the forecasts for NRW - almost all the spruce stands in the state
will be destroyed.
If the spruces are no longer there, the bark beetle will move on.
The spruce bark beetle also feeds on pine, larch and Douglas pines.
Lately the beetles have moved on to beech and oak.