Werner Eugster

Last Name

Eugster

First Name

Werner

ORCID

0000-0001-6067-0741

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Publications 1 - 10 of 225

Alpine vascular plant species richness
Vonlanthen, C.M.; Kammer, P.M.; Eugster, Werner; et al. (2006)
Plant Ecology
Performance of a low-cost methane sensor for ambient concentration measurements in preliminary studies
Eugster, Werner; Kling, G. W. (2012)
Atmospheric Measurement Techniques
Methane is the second most important greenhouse gas after CO2 and contributes to global warming. Its sources are not uniformly distributed across terrestrial and aquatic ecosystems, and most of the methane flux is expected to stem from hotspots which often occupy a very small fraction of the total landscape area. Continuous time-series measurements of CH4 concentrations can help identify and locate these methane hotspots. Newer, low-cost trace gas sensors such as the Figaro TGS 2600 can detect CH4 even at ambient concentrations. Hence, in this paper we tested this sensor under real-world conditions over Toolik Lake, Alaska, to determine its suitability for preliminary studies before placing more expensive and service-intensive equipment at a given locality. A reasonably good agreement with parallel measurements made using a Los Gatos Research FMA 100 methane analyzer was found after removal of the strong sensitivities for temperature and relative humidity. Correcting for this sensitivity increased the absolute accuracy required for in-depth studies, and the reproducibility between two TGS 2600 sensors run in parallel is very good. We conclude that the relative CH4 concentrations derived from such sensors are sufficient for preliminary investigations in the search of potential methane hotspots.
TreeNet–The Biological Drought and Growth Indicator Network
Zweifel, Roman; Etzold, Sophia; Basler, David; et al. (2021)
Frontiers in Forests and Global Change
The TreeNet research and monitoring network has been continuously collecting data from point dendrometers and air and soil microclimate using an automated system since 2011. The goal of TreeNet is to generate high temporal resolution datasets of tree growth and tree water dynamics for research and to provide near real-time indicators of forest growth performance and drought stress to a wide audience. This paper explains the key working steps from the installation of sensors in the field to data acquisition, data transmission, data processing, and online visualization. Moreover, we discuss the underlying premises to convert dynamic stem size changes into relevant biological information. Every 10 min, the stem radii of about 420 trees from 13 species at 61 sites in Switzerland are measured electronically with micrometer precision, in parallel with the environmental conditions above and below ground. The data are automatically transmitted, processed and stored on a central server. Automated data processing (R-based functions) includes screening of outliers, interpolation of data gaps, and extraction of radial stem growth and water deficit for each tree. These long-term data are used for scientific investigations as well as to calculate and display daily indicators of growth trends and drought levels in Switzerland based on historical and current data. The current collection of over 100 million data points forms the basis for identifying dynamics of tree-, site- and species-specific processes along environmental gradients. TreeNet is one of the few forest networks capable of tracking the diurnal and seasonal cycles of tree physiology in near real-time, covering a wide range of temperate forest species and their respective environmental conditions.
Integrated management of Swiss cropland is not sufficient to preserve its soil carbon pool in the long-term
Emmel, Carmen; Winkler, Annina; Hörtnagl, Lukas; et al. (2018)
Biogeosciences Discussions
Croplands are involved in the exchange of carbon dioxide (CO2) between the atmosphere and the biosphere. Furthermore, soil carbon (C) stocks play an important role in soil fertility. It is thus of great interest to know whether intensively managed croplands act as a net source or sink of atmospheric CO2 and if soil C stocks are preserved over long timescales. The FluxNet site CH-Oe2 in Oensingen, Switzerland, has been operational since the end of 2003. This cropland is managed under the Swiss framework of the Proof of Ecological Performance (PEP, a variant of integrated management) with a crop rotation centred on winter wheat, which also includes winter barley, winter rapeseed, peas, potato and intermediate cover crops. In addition to eddy covariance measurements, meteorological and soil measurements were available along with information on C imports and exports from organic fertilisation, sowing and harvesting. This study investigates cropland C budgets over 13 years and assesses whether the PEP regulations resulted in a balanced C budget. The strongest CO2 uptake was observed during cereal seasons. C export through harvest, however, offset the strong uptake of the cereal crops. The largest net CO2 emissions to the atmosphere were observed during pea and cover crop seasons. Net biome production, representing the overall C budget (assuming carbon leaching to groundwater to be negligible), typically ranged between close to C neutral to C losses of up to 407gCm−2 per season, with peas being the largest source. Overall, the field lost 1674gCm−2 over 13 years (129gCm-2yr−1), which was confirmed by soil C stock measurements at the beginning and the end of the study period. Although managing the field under the regulations of PEP did not result in an overall C sink, model simulations showed that the use of cover crops reduced the C losses compared to leaving the field bare. The use of solid manure improved the C budget by importing substantial amounts of C into the soil, while liquid manure had only a small effect. We thus conclude that additional efforts are needed to bring Swiss management practices closer to the goal of preserving soil C in the long term.
Sustainable agroforestry for carbon sequestration to improve small farmers’ livelihood in the tropics
Buchmann, Nina; Eugster, Werner; Dorn, Silvia; et al. (2007)
Annual report
Development of a land surface model including cloud water deposition on vegetation
Katata, Genki; Nagai, Haruyasu; Wrzesinsky, Thomas; et al. (2008)
Journal of Applied Meteorology and Climatology
A fault-tolerant eddy covariance system for measuring CH4 fluxes
Eugster, Werner; Plüss, Peter (2010)
Agricultural and Forest Meteorology
CO2 exchange of a grassland and a wetland in the Swiss Pre-Alps during the 2003 heat wave
Rogiers, N.; Furger, M.; Eugster, Werner (2006)
Geophysical Research Abstracts
Quality control of CarboEurope flux data: Part 2: Inter-comparison of eddy-covariance software
Mauder, Matthias; Foken, Thomas; Clement, Robert J.; et al. (2008)
Biogeosciences
As part of the quality assurance and quality control activities within the CarboEurope-IP network, a comparison of eddy-covariance software was conducted. For four five-day datasets, CO2 flux estimates were calculated by seven commonly used software packages to assess the uncertainty of CO2 flux estimates due to differences in post-processing. The datasets originated from different sites representing different commonly applied instrumentation and different canopy structures to cover a wide range of realistic conditions. Data preparation, coordinate rotation and the implementation of the correction for high frequency spectral losses were identified as crucial processing steps leading to significant discrepancies in the CO2 flux results. The overall comparison indicated a good although not yet perfect agreement among the different software within 5–10% difference for 30-min CO2 flux values. Conceptually different ideas about the selection and application of processing steps were a main reason for the differences in the CO2 flux estimates observed. A balance should be aspired between scientific freedom on the one hand, in order to advance methodical issues, and standardisation of procedures on the other hand, in order to obtain comparable fluxes for multi-site synthesis studies.
The net biome production of full crop rotations in Europe
Kutsch, W.L.; Aubinet, M.; Buchmann, Nina; et al. (2010)
Agriculture, Ecosystems & Environment

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