With the weather turning warmer, the activity of the European spruce bark beetle has begun in Latvia's forests. The European spruce bark beetle is considered the most aggressive and dangerous pest of spruce stands in Latvia, capable of infesting not only weakened spruce trees but also perfectly healthy ones. The State Forest Service has prepared recommendations on what forest owners should and should not do to reduce the damage caused by the pest.

The European spruce bark beetle (Ips typographus) is the most dangerous pest in mature spruce stands, not only in Latvia but throughout Eurasia. Spruce stands aged approximately 50 years and older are considered at-risk, as thicker trees are more suitable for the beetle's development. Most often, the beetle multiplies rapidly after windthrow, but it can also infest otherwise weakened spruce stands, for example, if trees have been rocked by wind, their roots have been flooded for a long time, or the trees have suffered from prolonged drought.

According to monitoring data from the Latvian State Forest Research Institute ”Silava”, the highest risk of European spruce bark beetle outbreaks this year could be in Sēlija and Vidzeme, but an outbreak of the pest cannot be ruled out in other parts of Latvia. “However, it must be emphasised that, just like last year, it is impossible to accurately predict how the beetle situation will unfold this year, so it is necessary to follow forest sanitation measures. The State Forest Service invites forest owners who have spruce stands on their property to take note of our prepared recommendations,” says Andis Purs, Head of the Forest and Environmental Protection Division at the State Forest Service.

What should a forest owner do?

In the second half of May and early June, owners should inspect the trunks of fresh spruce trees (especially if the trees have been felled, rocked, or otherwise damaged) to check for small, approximately 1 mm long holes (i.e., insect entry points), as well as fresh bark dust at the base of the tree trunk. If such signs are detected, the forest owner must report these observations to the State Forest Service. Damaged spruce trees should be removed from the forest as soon as possible, in accordance with the conditions mentioned below. On the other hand, the beetle no longer inhabits already dead spruce trees, such as those where the bark is peeling off, so they are no longer dangerous to the forest.

What should a forest owner NOT do?

In the period from 1 April to 1 September, it is strictly forbidden to carry out thinning or selective sanitary felling in spruce stands older than 50 years. Exceptions are permitted only in cases where the spruce stands are compact and isolated, and located at least 100 metres from other mature spruce stands. Such stands are allowed to be harvested via clear-cutting, felling the entire stand in one operation. This must be done in accordance with Cabinet Regulation No. 935 of 18 December 2012, “Regulations on Tree Felling in Forest Lands”.

The State Forest Service draws the attention of forest owners to the fact that the Service will not be providing owners with beetle pheromone traps this year.

If forest owners have any questions regarding measures to limit the spread of the European spruce bark beetle, the State Forest Service invites them to contact the senior experts of the Service's Forest and Environmental Protection Division:

• Oskars Zaļkalns – phone: 26188968; e-mail: oskars.zalkalns@vmd.gov.lv

• Vasilijs Kolačs – phone: 29441040; e-mail: vasilijs.kolacs@vmd.gov.lv
Photograph by Agnis Šmits used