Flurin Sutter

Bewirtschaftung und Umweltbedingungen beeinflussen die Gestalt von Wäldern. Mit der Einrichtung eines Naturwaldreservats wurden am Bettlachstock im Kanton Solothurn die Weichen zur Entwickung in Richtung eines Naturwaldes gestellt. Im Waldreservat werden im Rahmen des «Monitoring Naturwaldreservate Schweiz» mit Stichprobeninventuren die natürlichen Prozesse der Waldentwicklung und in der «Langfristigen Waldökosystemforschung (LWF)» mit kontinuierlichen Messungen der Einfluss von Luftverschmutzung und Klimawandel auf den Wald erforscht. Beides sind langfristige Untersuchungen, die Methoden der Waldinventur und Erfassung des Waldzustandes verwenden. Das Reservat ist aufgrund der Standortsvielfalt reich an verschiedenen Baumarten. Diese widerspiegeln das natürliche Artenspektrum. Der hohe Anteil an Fichten zeigt jedoch, dass die frühere Bewirtschaftung diese bewusst gefördert hat. Die Luftbelastung und das Klima hatten und haben nachweislich einen Einfluss auf den Wald am Bettlachstock. Die Die Luftbelastung ist eher rückläufig und die Klimaveränderung eher zunehmend. Beide stehen aus heutiger Sicht grundsätzlich der Entwicklung zu einem naturnahen Wald an diesem Standort nicht im Wege. Eine Zunahme von trockenen Sommern ist zu erwarten und könnte die Standorteigenschaften verändern. In Teilen des Reservats könnte dies mittelfristig zu vermehrtem Absterben von Tannen und Fichten und in der Folge zu einer Zunahme des Totholzvolumens führen. Langfristig könnte dies Verschiebungen der Höhenstufen und in der Baumartenzusammensetzung hin zu mehr Laubbaumarten auslösen.

Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its temporal dynamics are of significant importance, since their effects might change over the course of the decomposition process. Within the TeaComposition initiative, we incubated Green and Rooibos teas at 524 sites across nine biomes. We assessed how macroclimate and atmospheric inorganic N deposition under current and predicted scenarios (RCP 2.6, RCP 8.5) might affect litter mass loss measured after 3 and 12 months. Our study shows that the early to mid-term mass loss at the global scale was affected predominantly by litter quality (explaining 73% and 62% of the total variance after 3 and 12 months, respectively) followed by climate and N deposition. The effects of climate were not litter-specific and became increasingly significant as decomposition progressed, with MAP explaining 2% and MAT 4% of the variation after 12 months of incubation. The effect of N deposition was litter-specific, and significant only for 12-month decomposition of Rooibos tea at the global scale. However, in the temperate biome where atmospheric N deposition rates are relatively high, the 12-month mass loss of Green and Rooibos teas decreased significantly with increasing N deposition, explaining 9.5% and 1.1% of the variance, respectively. The expected changes in macroclimate and N deposition at the global scale by the end of this century are estimated to increase the 12-month mass loss of easily decomposable litter by 1.1-3.5% and of the more stable substrates by 3.8-10.6%, relative to current mass loss. In contrast, expected changes in atmospheric N deposition will decrease the mid-term mass loss of high-quality litter by 1.4-2.2% and that of low-quality litter by 0.9-1.5% in the temperate biome. Our results suggest that projected increases in N deposition may have the capacity to dampen the climate-driven increases in litter decomposition depending on the biome and decomposition stage of substrate.

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and metaanalyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from −9 to +26 °C MAT and from 60 to 3113mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained b0.5% of the variation for Green tea and 5% for Rooibos tea, and was of significance only under unfavorable decomposition conditions (i.e. xeric versus mesic environments).When the data were aggregated at the biome scale, climate played a significant role on decomposition of both litter types (explaining 64% of the variation for Green tea and 72% for Rooibos tea).No significant effect of land-use on early stage litter decompositionwas notedwithin the temperate biome. Our results indicate that multiple drivers are affecting early stage littermass loss with litter quality being dominant. In order to be able to quantify the relative importance of the different drivers over time, long-term studies combined with experimental trials are needed.

Terrestrial Laser Scanning (TLS) has great potential in creating high resolution digital elevation models (DEMs). However, little is known about the properties of TLS derived DEMs covering several hectares in heterogeneous environments compared to conventional airborne laser scanning (ALS) based models and their influence on derived products. We investigated the accuracy of DEMs with different resolutions derived from TLS and high quality ALS on a study site with complex micro-topography covered by dense forest and ground vegetation. We further examined the effect of these DEMs on predicted topsoil pH using linear regression models built on terrain attributes. We show that at high resolutions (∼1 m), TLS based DEMs performed better than ALS DEMs, which directly translated into significantly better pH models, the best of which showing an R² of 0.62. The use of TLS therefore improves the quality of terrain attributes, which are the foundation for many ecological and hydrological applications.

The two storms Vivian (1990) and Lothar (1999) left an area of roughly 9000 ha of fully damaged protection forests in Swiss mountain regions. Given this huge dimension, questions arose on how to manage these areas to keep the protection gap, i.e. the time period with reduced overall protection against natural hazards, short. Quantifications are presented for the stability of lying logs left in place, the frequency of post-disturbance mass movements, and the tree regeneration in windthrow areas. The average height above ground of unsalvaged lying logs decreased from 2.1 m shortly after disturbance to 0.8 m 20 years later. In the period 1990–2014, the number of avalanches in windthrow areas was markedly small, and annual rates of shallow landslides and debris flows in windthrow areas did not differ from rates in comparable undamaged forested areas. Regeneration density rarely exceeded 4000 stems ha^–1 20 years post-windthrow at elevations above 1200–1500 m a.s.l. Mean height of tallest trees reached 5.6 m in areas that were cleared and 6.5 m in those left unsalvaged. Trees planted post-windthrow were 1.0–2.4 m taller than naturally regenerated ones. Practitioners rated the protective effect to be acceptable 24 years post-disturbance in only 5 out from 16 observed windthrow areas (31%), with planting trees as the main cause of success. We conclude that in protection forests the regeneration speed after disturbance rarely meets practitioner's expectations in terms of both stem density and stand structure. However, leaving woody debris from wind disturbance in place proved to replace protective effects for an astonishingly long time. An intensive management with salvage logging, planting and even technical constructions seems therefore only inevitable on windthrown areas where risks seem too high based on hazard, damage potential and possible spread of bark beetles to nearby protection forests. A management alternative applicable to many other cases of windthrown protection forests is to plant trees between lying stems.

This study compares the surface wind speed and forest damage data of two exceptionally severe winter storms, Vivian 1990 and Lothar 1999. The study area comprises the region that suffered damage in Switzerland. The wind speed data were derived from simulations of MeteoSwiss (Federal Office of Meteorology and Climatology), measurements during the storm periods and expert analyses of the data. The remotely sensed forest damage data were provided by the Federal Office for the Environment and the forest cover data by Swiss Federal Statistical Office. We compared data on the peak gust and maximum average wind speed, with data on the spatially related forest area and forest damage area, and found some clear differences in the correlations between the different wind data and forest damage. Our results point generally to the damage-causing role of near-surface gusts at maximum wind speeds during the storm. These tended to be spatially distributed on a fine scale. In only a few cases were the results statistically significant. However, these results could probably be improved with better wind data. For example, gust measurements spatially closer to forests or simulations of gusts at maximum wind speed could be produced with a spatially higher resolution.

In environmental ecosystem research, there is a trend towards sharing research sites infrastructure among project partners when carrying out individual or common projects. As a result a growing number of so-called research platforms are established. In order to take advantage of most of the potential synergies between project partners an adequate ICT infrastructure must be provided. This paper describes an ICT application which fully automates the workflow from measuring parameters in remote gauging stations up to storing validated time-series in a database. The main focus is on designing an appropriate database, but issues of software design and necessary standardization are also included.

Während des Ereignisses führte die Verklausung von Schwemmholz an Brücken und Wehren verschiedentlich zu einer Verschärfung der Hochwassersituation. Das vorliegende Kapitel enthält eine Übersicht über die dokumentierten Schwemmholzmengen, sowie Ergebnisse weitergehender Untersuchungen über das Schwemmholzaufkommen in vier Wildbächen und über die Zusammensetzung ausgewählter Schwemmholzablagerungen.

Two different replacement investment strategies, derived from two case studies within Swiss Forest Ecosystem Research, are assessed for sustainability in terms of dematerialization and low rebound effect. The so-called broad strategy uses a broad focus on the whole replacement investment field. It includes analysing and optimising all processes and workflows and then choosing the appropriate hard- and software components. It is the mainstream replacement investment strategy nowadays. The narrow strategy has the goal of keeping the old, possibly already optimised workflows and processes and using modern "dematerialised" devices. The advantages of this strategy are a low or no rebound in combination with a considerable dematerialization effect. This approach is often ignored in today's IT investment decisions. The two strategies can be combined to find an optimal, project-specific solution.

Several aspects of data management are very similar in both current ecological research and the modern business world: the volume of data acquired is high and financial resources are scarce. Therefore it is necessary to implement efficient automated processes for everyday data acquisition and data management. Recent innovations in telecommunication technology (i.e. use of the GSM-Network for digital data transfer) allow the inexpensive acquisition of data from remote research plots. Such innovations in combination with scarce financial resources force ecological research organisations to transform their work flows in the field of automated data acquisition. This paper will show an example of how Business Engineering methods can be usefully adapted in the world of science, especially in the field of ecological research.