The European spruce bark beetle (Ips typographus) has had a devastating impact on the forests of Germany. Rising temperatures and droughts have made the country’s trees more susceptible to attacks by bark beetles and other insects, leading to a nearly six-fold jump in trees being destroyed by pests in the last two years. Amid fears a similar outbreak could happen in the UK, Forestry Journal approached German forester Michael Sommer to share his experience.

Foresters are battling to save Germany’s forests, which are under threat from a number of factors, chief among them the European spruce bark beetle (Ips typographus). The figures are stark. Around 32 million cubic metres of wood damaged by insects had to be removed from Germany’s forests in 2019, according to the Federal Statistical Office. That total is three times higher than the 11 million cubic metres that was destroyed in 2018, and an almost six-fold increase on the 6 million cubic metres felled due to pests in 2017. Soaring temperatures and droughts have created the perfect conditions for a small insect to make a devastating impact.

Forestry Journal: Michael Sommer.Michael Sommer.

For the last 18 years, Michael Sommer has been managing private forest grounds and hunting estates through his company Forstkontor Sommer. His team of skilled specialists arranges and carries out all the forestry work, from planting, over thininngs and loggings to timber sales and hunting management on these privately owned grounds. He is based in the southern part of Nordrhein Westfalen, the ‘Sauerland’ about one hour east of Cologne, a region dominated by rolling hills and vast spruce forests.

Until now...


The first signs of this beetle catastrophe were noticed by us on one particular estate, which is on elevations from 150–250 metres above sea level in early 2018. While most foresters were being kept busy with cleaning up the windblow of some local storms, we noticed the quick development of a potential mass Ips infection.

Forestry Journal: High temperatures and strong winds have combined to aid the beetles’ progression through German forests.High temperatures and strong winds have combined to aid the beetles’ progression through German forests.


Since the big storm Kyrill in 2007 we have had some very local and limited infection sites, mainly along the edges of the clearfell boundaries or next to windblown spots scattered through the tree stands. So a major focus was on finding those ‘nests’ and cleaning them up. In the spring of 2018 those nests multiplied almost overnight and began occurring in many places that had appeared cleaned up. The beetles spread out from those spots, using the warm and dry weather mixed with high wind speeds to drift into the neighbouring healthy spruce stands. The spruce trees obviously couldn’t defend themselves and couldn’t bleed out the invading beetles with their tar. The dry soil, reduced humidity and high easterly winds weakened the individual tree and the whole stands, so it was easy game for the Ips family to develop up to four generations in one season.


I guess it was the result of several very special circumstances coming together. Left-over rests from windthrow all over the forests with slash drying out quickly allowed the beetles to breed. The edges of forests and tree stands had been weakened through wind and insect damage from past years. High temperatures mixed with strong easterly winds dried out the soil and weakened trees, starting with the flat-rooting spruce. There was also a total misjudgement of the whole situation, with forestry commissions across the country not getting proper information about a realistic quote for the windthrow, the first infection rate of Ips hitting the spruce stands or the problems with logging, yarding and selling the timber immediately. The government totally failed to hear the first alarming news and waited till late autumn to arrange the first meeting of a countywide task force.

Forestry Journal: The European spruce bark beetle (Ips typographus) is a common and potentially devastating pest which tunnels under bark, cutting off the supply of food and water the tree needs to survive.The European spruce bark beetle (Ips typographus) is a common and potentially devastating pest which tunnels under bark, cutting off the supply of food and water the tree needs to survive.


We tried to act as quickly as possible, cleaning out all windthrow – even single trees – as potential Ips habitat. We tried to find all the infected stands and spots, clear out all nests, log the timber in time, get it out of the forests and to the sawmills straight away. Any timber which couldn’t be sold quickly enough was treated with a selective insecticide (another problem: only two insecticides were approved for use by the government). We tried to make the tonnes of slash as unattractive for Ips as possible by mulching or even burning it (burning was mostly impossible because of the dryness and high-speed winds). We thought a quick clean-out would reduce the population. Obviously that was a total misjudgement and countrywide fail.


The first effect was a huge overload for my colleagues and me. We searched for infected trees every day, tried to arrange the loggings, organized timber sales, measured the timber, established overseas contracts, the loading of containers and shipments abroad. None of this fitted into our ‘normal’ forestry management contract work.

The next effect was a change in the main focus of our work. From long-term planning, marking logging and thinning units, and selling a specific amount of timber, we had to switch over to only marking boundaries, measuring mass shipments and focussing on logging processes. All thoughts of silvicultural work went into the background.

We do see a lot of requests for hunting management to reduce deer populations, for help with applying for funding and support to replant clearcuts, and, before that, requests for help selling the huge amounts of timber to any markets we can.

A long-term effect will be that a lot of landowners will struggle to afford proper forestry management in the future. We might have to focus on those landowners who rely on government funding.

Forestry Journal: Damaged logs need to be harvested as soon as possible, which has had a serious knock-on effect on production.Damaged logs need to be harvested as soon as possible, which has had a serious knock-on effect on production.


The timber market for spruce and pine trees collapsed totally. Prices are down to about 15 per cent of what they would normally be. A high percentage of the dead trees can’t be sold at all. Landowners and foresters have to decide which stands to cut and which to leave. Smaller-diameter trees, and tree stands on steep slopes or with high logging costs will be left to die standing, because the costs will be higher than the income through selling the timber.

Without the export of timber, mainly to Asia, there wouldn’t be any big logging going on right now. We don’t discuss any prices, only how much timber to sell and where to.

It’s hard to find a logging company available to work on a long job, because they need to drive from stand to stand, from landowner to landowner to help them all a bit at a time.

Foresters, landowners and logging companies are working harder than ever and feel the emotional strain of working while surrounded by dying trees all the time. Burn-outs and even suicides are increasing.

Landowners are losing their income and seeing their future eroded, even with their ‘safe’ retirement payments.

The public recognises the importance of the death of the woodlands, mainly as it affects recreational sites and much-needed carbon storage. The forestry industry has been urged to replant as soon as possible. This public and political pressure, in combination with the situation around climate change and the new, unexpected, even higher rate of infection in even more spruce stands in all elevations and regions of our country is pushing the whole industry into a kind of depression.


Until late in 2018, it offered nothing. Right now, timber trucks are allowed up to 44 tonnes (instead of 40). Nordrhein-Westfalia and most other counties set up special funding programmes, primarily to support the landowners. There have also been logging bonuses, funds for clearing up slash and to help with replantation costs (though we can’t replant into this dried-out soil). Indirect support has come through scientific surveys and instruction about how best to react.


Yes, we should have been given the opportunity to contribute to the decision on insecticides. Instead, because of environmentalists and a nationwide decline of insects in general, no-one was willing to get into a debate.

Landowners need more support and help dealing with all the timber. German forests should receive continuous funding for their multifunctional benefits: cleaning air and water, supplying industry, offering recreation for everybody. It should be something like a ‘carbon penny’ paid by everyone, as a kind of tax, to support the landowners, show them some respect and help to get new forests started.

A nationwide catastrophe plan is long overdue. The whole industry must work together and support each other. It will only work when foresters are there to judge the dimension of a catastrophe, deciding together with landowners, industry and the government how to react. It won’t work if different groups, counties, sawmills, landowners and politicians are permitted to continue to act selfishly, isolated and uninformed.

Forestry Journal: Scenes like this are now common across Germany's forests.Scenes like this are now common across Germany's forests.


React ASAP! Take out any infected tree, destroy the slash, spray the timber with insecticides and get the timber to the sawmill, out of the forest immediately.

Act together! Speak with landowners, foresters, logging companies and the timber industry to arrange a defending and logging/selling plan.

My long-term advice is that we have to realize all monoculture structures, even if they developed very well so far, are easily effected and eradicated by catastrophes like a mass infection with Ips typographus and its ‘friends’.

Start with a proper investigation about your deer population and its impact on tree stands and new plantations. Only constructive land management will secure our productive and stable forests of the future.

For anyone interested in getting a view on our actual situation and our work with Ips and its effects, you are always welcome to visit us and get a very personal impression of this disaster.

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