Debarking harvesters simultaneously combat the European spruce bark beetle Ips typographus and conserve non-target beetle diversity

In the face of climate change, the European Spruce Bark Beetle (Ips typographus) breeding predominantly in Norway spruce (Picea abies) led to exceptional amounts of damaged timber in European forests. Up to now, if pest control is applied, damaged or weakened P. abies trees are either extracted by salvage logging or, when quantities are low, made unsuitable for breeding by manual debarking techniques. Both pest control interventions are costly, are often limited by the short timeframe of effectiveness and come with negative impacts on the non-target biodiversity. As alternatives for timely removal, a debarking head for harvesters for large scale disturbances and a bark gouging device for motor-manual treatment have been developed in recent years to make breeding material unsuitable for bark beetles and reduce existing larvae. Based on data from an experimental design with infested Norway spruce logs, we show that the harvester debarking head and the motor-manual bark gouging regulate I...., The study was conducted in the buffer zone of the Bavarian Forest National Park, where active bark beetle interventions are implemented (N 49° 5' 13'' E 13° 14' 0''). Forest stands in this area are dominated by P. abies and have experienced extensive I. typographus outbreaks in the past. Sixteen P. abies trees of similar size, age and with signs of early colonization (white larval stage without teneral beetles) by I. typographus were felled in June 2020. All trees met the criteria for removal of the regulations for the buffer zone management and were randomly assigned in groups of four trees to each of the treatments, to account for potential differences in colonization densities between trees. The control trees were felled without any further bark manipulation. After felling, delimbing, and cutting into sections, the second group was treated with the bark gouging device attached on a conventional chainsaw (“Streifenmesser Nationalpark Bayerischer Wald”, EDER Maschinenbau GmbH, Wolfenbü..., , # Debarking harvesters simultaneously combat the European spruce bark beetle (*Ips typographus*) and conserve non-target beetle diversity

[https://doi.org/10.5061/dryad.4f4qrfjmr](https://doi.org/10.5061/dryad.4f4qrfjmr)

We compared different methods of mechanical bark treatments for the regulation of *Ips typogrpahus* populations in freshly cut and colonzed spruce logs and their effect on non-target beetle diversity. From each log, three segments, measuring 70 cm, were cut out at random locations to account for differences of colonization densities within the logs. The 48 segments (12 per treatment) were placed in rearing barrels to collect abundances of all emerging arthropods from June until October 2020. All beetle species were separated from other arthropods and identified to species level by taxonomic expert Andreas Weigel.

The four treatments were: Control (K), conventional Harvester (NH), bark gouging (PS) and Harvester Debarking Head (DH)

Results: The harvester debarking he...