A dangerous oak disease, acute oak decline (Acute oak decline), continues to spread in Latvia. The disease has been observed in various locations across Latvia, with the highest concentration of affected trees in the Talsi area. Oaks affected by the disease die relatively quickly, usually within three to five years of symptoms appearing. The State Forest Service urges people to pay attention to oak trunks and check for signs of the disease. If any are spotted, report them to State Forest Service specialists.

Acute oak decline is caused by several species of bacteria, the two most common being Gibbsiella quercinecans and Brenneria goodwinii . These bacteria have also been identified in dying oak trees in the Talsu Pauguraine nature park.

Acute oak decline is particularly widespread in Great Britain, where intensive research into the disease is currently underway. According to British scientists, the disease mainly affects mature oaks—those older than 50 years with a diameter at breast height of more than 30 cm. The disease threatens oaks in both natural and artificial ecosystems, including forests, parks, agricultural land, and urban environments.

The most important sign to recognise the disease by is the dark, sticky fluid (exudate) weeping from the trunk of the infected tree, which emerges through small, vertical cracks. These wounds are approximately 10–20 cm long and 1–2 cm wide. Initially, the release of the dark fluid is observed one to two metres above the ground, but it may subsequently be observed in the tree canopy; fluid release is usually observed in spring (March–June) and autumn (October–November). Extensive weeping wounds with fermenting sap are not a sign of this disease, stresses Oskars Zaļkalns, senior expert at the Forest and Environmental Protection Department.

The SFS urges everyone to pay attention to oak trunks and check whether signs of the disease—small vertical cracks—are visible. If such cracks are observed, please inform the service's specialists:

• Oskars Zaļkalns – phone: 26188968; email: oskars.zalkalns@vmd.gov.lv
• Vasilijs Kolačs – phone: 29441040; email: vasilijs.kolacs@vmd.gov.lv

Since 2017, the State Forest Service has been surveying oak stands to identify acute oak decline. This year, the State Forest Service (SFS) plans to survey 197 forest stands containing oaks of various ages. The primary area for the surveys will be Vidzeme and Latgale, while individual stands will also be surveyed in the rest of Latvia.