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Seidl I.,Eidgenossische Forschungsanstalt fur Wald
Schweizerische Zeitschrift fur Forstwesen | Year: 2015

Future land use may well lead to increasing conflicts between the competing demands for this scarce and limited resource given demands, interests and societal developments. Three approaches to dealing with land use are proposed: multifunctionality, quality of land use and sufficiency. Additionally, beauty needs to gain in importance. The foundation for the proposed approaches needs to be an institutional and cultural transformation that includes the construction industry, the ideological basis of municipal planning, as well as the societal drive for growth, and money creation.

Kaufmann E.,Eidgenossische Forschungsanstalt Fur Wald
Schweizerische Zeitschrift fur Forstwesen | Year: 2011

In the Swiss National Forest Inventory (NFI), the data collected in the three inventories (NFI1 1983-1985, NFI2 1993-1995, NFI3 2004-2006) provide the basis not only for analysing the present state of the forest and how it has developed up to now, but also for assessing, with the help of models, how it might develop in future. The scenario model «Massimo 3», developed at the Swiss Federal Institut for Forest, Snow and Landscape Research, is an empirical and stochastic simulation model. It relies on data from the NFI and forecasts the development of the forest according to how it is managed. Six scenarios with different management regimes were defined according to the economic, silvicultural and ecological aspects considered. In three scenarios the growing stock is kept constant at the level of NFI3, but different management strategies are used (Scenario A: basis [business as usual], Scenario E: even-aged forests are transformed into uneven-aged forests, and Scenario F: near-natural percentages of conifers are promoted). In two scenarios forest management is partially abandoned for either ecological reasons (Scenario B: reservations, 10% of the forest area is left unmanaged) or for economic reasons (Scenario C: harvesting costs, 40% of the forest area is left unmanaged). Scenario D (rotation periods are shortened) was used to study the effects of augmenting the annual harvesting amount. A forecasting time period of 100 years was selected to assess the long-term effects of the scenarios. Scenarios A, D, and E show that the sustainable harvesting potential of merchantable wood lies in a relatively narrow range of 7.1 to 7.3 million m3/year, even though in Scenario D the growing stock is reduced from 360 m3/ha to 305 m3/ha. In Scenario F regeneration is systematically established with near-natural percentages of conifers, the long-term harvesting potential is slightly less: about 6.5 million m3/year of merchantable wood. If forest management is abandoned for economic reasons on as much as 40% of the forest area (Scenario C, harvesting costs), the impact on the wood reserves is very negative.

Hirschi C.,ETH Zurich | Huber R.,Eidgenossische Forschungsanstalt fur Wald
Agrarforschung Schweiz | Year: 2012

This contribution reveals how the agricultural provision of ecosystem services in Switzerland is supported by the agricultural policy making process. Based on the analysis of the agricultural policy reform processes AP 2011 and AP 14-17, the policy network and the policy positions of the individual network actors with respect to a further greening of the agricultural policy are identified. The results reveal the willingness of the actors to strengthen and to support the provision of ecosystem services with targeted direct payments. To secure such payments in the long run, two aspects have to be taken into account: i) the linkage of a further greening of the agricultural policy with concomitant policy changes such as market liberalization or deregulation and ii) the development of the overall economy as well as the budget of the public authorities.

Brassel P.,Eidgenossische Forschungsanstalt Fur Wald
Schweizerische Zeitschrift fur Forstwesen | Year: 2011

The idea of carrying out a national forest inventory in Switzerland was first raised in the 1950s. It had become increasingly evident that such an inventory was lacking as a basis for evaluating the state of the forest in the whole country. But it was not until 1970 that this idea took concrete shape. And it took another ten years for the Swiss government to agree to the first inventory taking place. From the start, the National Forest Inventory (NFI) was a joint project of the Swiss federal administration and the Swiss Federal Research Institute WSL. It has now established itself as an objective source of information about the Swiss forest. On the national level, it is today the most important instrument for monitoring the sustainability of the management of Swiss forests, and it yields the main data needed for international reports on forests. The success of the NFI is at least partly due to the fact that it has met with widespread support from both the Swiss authorities and scientists. The NFI has, over the past 30 years, continuously developed both methodologically and in terms of content. Thus the first NFI's data catalogue was expanded to include, for example, numerous ecological parameters. Currently the fourth NFI is underway. It will mark the transition from a periodic to a continuous inventory. In the future, the survey results will be published roughly every three years. Reducing the intervals between inventories will, however, be associated with higher estimation errors. On the other hand, interesting new applications can be expected in remote sensing, as well as improved models of future forest development. Some new methods seem promising, like the so-called "small area estimation", which enables conclusions to be drawn about relatively small areas. However, if the NFI is to continue to perform its tasks adequately in future, it must receive sufficient funding.

There is an increasing interest on area-wide and high-resolution data of forest composition. In Switzerland, tree species distribution will be considered periodically by the Swiss National Forest Inventory (NFI), but the claims will be only partly fulfilled by the existing forest type maps since they are relatively poor regarding spatial accuracy, updating, and reproducibility. Providing consistent, reproducible and up-to-date information on various forest parameters is the main advantage of using the latest remote sensing data and methods. New possibilities are given by the airborne digital sensor ADS80, which records the entire country during the vegetation season every six years. This paper presents a robust methodology of classifying tree species in different study areas. The obtained accuracies for beech, ash, Norway spruce, Scots pine, larch, willow and silver fir are in average 71-85%, but lower for other deciduous tree species. These are mainly less dominant tree species within a study area such as maple and birch. A small sample data set and shadows of other neighboring trees seem to be the main reasons for this. Based on the experiences made in this study, a country-wide classification of tree species has become more feasible. The usage of airborne digital sensor ADS80 data in combination with a high degree of automation from the developed methods will enable the generation of country-wide products on the distinction of coniferous and deciduous tree species until 2015.

Wermelinger B.,Eidgenossische Forschungsanstalt fur Wald
Schweizerische Zeitschrift fur Forstwesen | Year: 2014

The rate of introduction of non-native insects and other arthropods to Europe has been exponentially increasing in recent decades, amounting to 20 species per year in the past ten years. By 2008, a total of 1590 species had been introduced since the discovery of America. The main causes are the intensification and globalization of international trade. The most important pathways are trade in ornamental plants and import of goods in infested wooden crates. Most often new species first establish in residential areas, where the normally mild climate favors the survival of exotic species. Three species recently introduced from East Asia to Switzerland are particularly relevant to forests: the box tree moth (Cydalima perspectalis) has infested box tree stands near Basel, the chestnut gall wasp (Dryocosmus kuriphilus) now covers almost all of southern Switzerland, with single infestations also on the Swiss Central Plateau, and two infestation spots of the Asian longhorned beetle (Anoplophora glabripennis) have been identified. Potential future species of invasive insects are discussed. The largescale introduction of foreign tree species in forests needs to be critically examined, as they may be hosts of current and future non-native insects.

Kolly A.C.,Eidgenossische Forschungsanstalt Fur Wald | Kupferschmid A.D.,Eidgenossische Forschungsanstalt Fur Wald
Schweizerische Zeitschrift fur Forstwesen | Year: 2014

Browsing of silver fir (Abies alba) saplings by ungulates is one of the most important issues concerning decreasing regeneration of this tree species. In addition to genetic drivers, environmental factors such as light availability play an important role for the response of a browsed tree. Using an experimental design with fences, we investigated the influence of natural browsing on tree growth along a light gradient. The few fir saplings that responded by flagging up a lateral shoot compensated the browsing induced height difference compared to unbrowsed trees within four vegetation periods. Most firs however reacted with new shoots and remained smaller than unbrowsed ones. The more often a fir sapling was damaged on its terminal shoot, the smaller the tree remained. A positive relation between tree height and light was found only up to a canopy openness of 11%. Mortality over the whole five years was high in low light (<10%) and in forest gaps (>15%), due to desiccation, competition with other plants or browsing (50% of total mortality). We recommend regenerating firs under moderately shaded conditions.

Wohlgemuth T.,Eidgenossische Forschungsanstalt fur Wald | Kramer K.,Eidgenossische Forschungsanstalt fur Wald
Schweizerische Zeitschrift fur Forstwesen | Year: 2015

Tree regeneration in Swiss forests after winter storms Lothar (1999) and Vivian (1990) was analysed based on a sample of 90 totally wind damaged forest gaps of at least 3 ha size, located in the Jura Mountains, the Central plateau, the Prealps and parts of the Alps. In the less elevated Lothar gaps (∅ 860 m a.s.l.) mean stem densities in no intervention gaps (NI) were 7,644 and in salvage logged gaps (SL) 10,786. Means in Vivian gaps (∅ 1428 m a.s.l.) were significantly smaller with 2,572 in NI and 4,600 in SL gaps. Pre-storm regeneration in Lothar gaps amounted to one third of the total stem density and in Vivian gaps to one tenth. The ten tallest trees in both Lothar and Vivian gaps were similar sized with 6.3 m and 6.5 m in average. Most abundant tree species were beech (Fagus sylvatica), sycamore (Acer pseudoplatanus), ash (Fraxinus excelsior) and Norway spruce (Picea abies) in Lothar gaps, and Norway spruce, sycamore and rowan (Sorbus aucuparia) in Vivian gaps. Stem density increased with soil pH and decreased with elevation and the portion of tall herbs, raspberry and blackberry. The deadwood volume amounted to average 266 and 285 m3 per ha in NI gaps of Lothar and Vivian, respectively. In the SL gaps, volumes averaged to 74 and 76 m3 per ha, respectively. Deadwood as regeneration substrate matters predominantly in forests at higher elevations and favouring Norway spruce in particular. Natural regeneration takes place in all studied forest gaps, sooner or later. To achieve specific forest aims, however, competing understory vegetation needs to be controlled. Our results serve as a reference for tree regeneration in wind damaged forests of Central Europe.

This review links the question of how herbivores s. str., namely consumers of green plants, struggle to obtain a sufficiently nutritious diet, to the ongoing discussion of top-down versus bottom-up regulation of ecosystems. The top-down view, known as the «world is green» hypothesis, which states that the green biomass is not completely removed by herbivores because they are controlled by predators, has recently been backed by a number of studies demonstrating cascading effects. In such cascades, apex predators restrict populations of large herbivores and so produce responses among lower trophic levels, as the vegetation is released from heavy browsing pressure. However, closer scrutiny of long-term data has shown that both top-down and bottom-up mechanisms may be operating in a system at the same time. The bottom-up view has originally been explained by the «world is prickly and tastes bad» hypothesis, stating that the lack of the herbivores' ability to consume large parts of the green biomass is due to the self-defense mechanisms of the plants. There are, however, better reasons to assume that the main cause of bottom-up effects is the problem of the herbivores to secure enough nitrogen from their plant diet. Strictly herbivorous birds are few but goose populations do respond strongly to increased quality in their grass diet whereas grouse, being essentially browsers, do not seem to be limited by their often extremely low-quality winter diet. Ungulate grazers, on the other hand, are strongly driven by the nutritional quality of their diet. This aspect is illustrated by two examples, one involving red deer Cervus elaphus in the Swiss Alps, the other a community of antelopes living in a wet tallgrass savanna in coastal Tanzania. In both cases, the all-important role of highly nutritious grasses (with low fiber and thus relatively high crude protein concentrations) for diet and habitat selection could be clearly demonstrated. In the case of red deer, altitudinal migrations tracked the protein-richest forage on offer, providing strong support for the forage maturation hypothesis.

Bollmann K.,Eidgenossische Forschungsanstalt fur Wald | Muller J.,Nationalpark Bayerischer Wald DE
Schweizerische Zeitschrift fur Forstwesen | Year: 2012

The question "How large should the total extent of strict natural forest reserves be?" dominates the current debate about the need of unmanaged forests for biodiversity conservation in Central Europe. However, within a system of close-to-nature forest management, the quality, location, composition and distribution of natural forest reserves might have higher impacts on the diversity of species, communities and natural processes than the reserves' extent alone. Strictly speaking, the correct answer about the minimal required surface is directly related to the superior conservation objectives. In addition, the required ratio of forest reserves in relation to the total forest area is influenced by other factors such as the abundance and distribution of forests pirmarily managed for conservation objective, protected forest biotopes and old-growth stands as well as the general standards for an integrative, close-to-nature silviculture. Since concrete, superior objectives for forest biodiversity conservation are still missing in Central Europe, we put the focus of this article on the criteria that influence the conservation-specific impact and quality of strict natural forest reserves. These are amongst others the extent and compactness of a reserve, its habitat continuity and connectivity, the representativeness of forest types, their species composition and biogeographic distribution, a reserve's site heterogeneity and naturalness of its vegetation as well as the abundance of key structures and target species.

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