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Forest Protection

Forest protection and pest management are crucial for successful and sustainable forestry. Research in these fields is multidimensional and covers biology, ecology, chemoecology, forest management, and more. Forest practitioners need fast and economic solutions, while nature conservation calls for low impact solutions and scientists hope to understand insect communication or the ecological processes behind insect outbreaks. We are addressing all of these aspects in our research.

Through our research, we aim to understand the basics of insect behavior, communication and dynamics, while also providing forest practitioners with practical knowledge. Most of our studies are carried out in close collaboration with the forestry sector, take place in the field and are supplemented by lab work and experiments conducted under semi-natural conditions.

Currently our main research focus is to improve the insecticide-free management of bark beetle populations on spruce and fir as well as on early detection and monitoring. We involve students in our research wherever possible, fusing research and teaching.


Current Projects

Development of an Application Strategy for SPLAT®Verb for Population Management of European Spruce Bark Beetles (Ips typographus) with the anti-aggregation Pheromone Verbenone

The Verblps project aims to test the effectiveness of the use of SPLAT®Verb against Ips typographus aggregation and infestation. While the pheromone dispenser SPLAT®Verb is already used to manage and contain a variety of bark beetle outbreaks for species such as the Mountain pine  beetle (Dendroctonus ponderosae) in the United States, its effectiveness has yet to be tested for the European spruce bark beetle Ips typographus.

SPLAT®Verb is a commercially produced and environmentally friendly pheromone dispenser that provides the controlled release of the anti-aggregation pheromone verbenone in the field. Verbenone is a naturally occurring anti-aggregation pheromone used by a variety of bark beetle species including I. typographus.

During this project, the effectiveness of the use of SPLAT®Verb against Ips typographus aggregation and infestation will be tested. The active inhibitory range, duration of effect and required quantities will be determined, its use for area protection will be investigated and application options presented.

This research is a joint project carried out by Chair of Forest Entomology and Forest Protection and the Chair of Ecosystem Physiology at the University of Freiburg together with the Forest Research Institute of Baden-Württemberg (FVA).


Bark Beetle Sound Production: Acoustics of the European Spruce Bark Beetle Ips typographus

Passive acoustic techniques may offer a remote, non-invasive, automated alternative to traditional methods in the detection and monitoring of hard-to-access species. In recent applications, incidental sounds produced by wood borers—such as those generated in the process of feeding or moving through galleries—have been used for the early detection of some species in imported wooden packaging goods. Although a species of high economic interest, no literature exists on the incidental sounds of the European spruce bark beetle Ips typographus.
Through a series of laboratory oscilloscope measurements, we carried out an investigation into the performance of currently available acoustic equipment in detecting Ips typographus incidental sounds. Additionally, we described incidental sounds in larval, pupal and adult Ips typographus, by comparing recordings taken in infested and uninfested logs. A series of video recordings were further collected of artificial plexiglas sandwiches infested with larval, pupal and adult Ips typographus to allow for acoustic-visual correlations between the identified sounds and movement.
Our measurements revealed high disparities between the compared recordings in terms of sensitivity and signal-to-noise ratio, highlighting the importance of the two parameters when measuring a low amplitude acoustic signal such as incidental bark beetle sounds. Furthermore, we found incidental sounds of Ips typographus to be characterized by broad-band, short, irregular pulses ranging between 100Hz and 22kHz.
Our findings can be a useful point of departure for future investigations into the acoustics of Ips typographus, and may provide a stepping stone for eventual applications of acoustic technology in the early detection, monitoring and management of this species.



Integrating Biodiversity to Evaluate and Optimize Timber-Harvesting Practices

The effects of timber harvesting machinery on the soil structure of forest skid trails have been relatively well investigated. Soil compaction alters soil physical parameters, leading to a decreased soil macroporosity and to an impaired pore continuity. This process sets a chain of reactions in motion, altering the gas and water balance of skid trail soils and presumably their species composition. However, the state of knowledge about the effects of heavy machinery traffic on biodiversity does not yet allow for clear interpretation and assessments. A combined analysis of soil physical, soil ecological and entomological investigations is missing, as is the determination of the site characteristics which mediate the effects of traffic on soil organisms. The goal of our study is to develop an evaluation guide for forest soil compaction based on these interrelationships, with microbial, soil faunistic and entomological examinations at the core of this development work. Thus, the open question that we aim to address is how the degree of soil compaction affects the biodiversity of soil organisms, exploring the link between the abiotic indicators of the disturbance intensity and the susceptibility of the biotic community to this influence.


Food quality of various broadleaved trees for maturation feeding of adult cockchafer (Melolontha hipposcastani)

In the Upper Rhine region, climate change poses massive challenges for forestry. In addition to
environmental changes due to climate change such as drought and heat, the local cockchafer
populations represent another dimension. The potential changes in the tree species spectrum will be
assessed in terms of risk from cockchafer and incorporated into a Species Distribution Modeling
(SDM) as scenarios. This arises because of differences in food quality for females during their
maturation feeding on leaves of deciduous trees, which affects egg production and thus reproductive
potential. Here, the differences between native and new alternative tree species, which are
considered to be climate stable, will be experimentally elaborated in two replicates. In addition to
the established tree species red oak, sessile oak and littleleaf linden, downy oak, Norway maple and
the neophytic black cherry will be tested in the feeding experiments.

Measuring the noise of the Ips typographus with the laboratory oscilloscope

© Raluca Hedes