Forests In Switzerland Research Articles

Agrarische Waldnutzungen in der Schweiz 1800–1950. Waldweide, Waldheu, Nadel- und Laubfutter | Agricultural use of forest in Switzerland 1800–1950. Wood pasture, wood hay collection, and the use of leaves and needles for fodder

The suppression of agricultural uses of the forests was a prerequisite for the successful introduction of sustainable wood production in the 19th and early 20th century. Today, these agricultural uses of the forests, which have been neglected for a long time, are being re-evaluated. They foster less dense and more open forest stands, which are of interest to nature conservation. In the present review paper we discuss the characteristics,extent, and intensity of historical agricultural uses of forests in Switzerland. We especially focus on the relationships between local people with entitlement rights of supply, the interests of the forestry officials, and more general processes,such as agricultural modernization and changes in the infrastructure of transportation. We also consider the ecological aspects of the resulting changes in forest structure. In the first part presented here, we focus on wood pasture and wood hay collection, both of which conflicted with wood production and with the concept of protective forests. As a third type of forest use we discuss the use of leaves and needles for fodder. In a second paper we will later review litter collecting and the temporary use of clearings in the forest as agricultural fields.

Risks of global warming on montane and subalpine forests in Switzerland ? a modeling study

In this study, we assess the risks of global warming on distributions of individual tree species in Switzerland. Applying a spatially explicit model, tree occurrence is predicted as a function of high resolution and physiologically relevant biophysical variables. The study shows that warming only slightly alters the overall abundance of tree species. However, the preferred temperature regimes are unevenly distributed along an elevational gradient, and the sensitivity to temperature varies considerably between the species. As a result, major reorganizations of forests in montane and subalpine belts are expected, i.e., a segregation of the core distributions of Fagus sylvatica and Picea abies is observed. Tree distribution potentials near timberlines, however, remain roughly the same.

Zukünftige Ausrichtung der Waldbeobachtung in der Schweiz | The Future Orientation of Forest Monitoring in Switzerland

In June 1999 the directors of both the Swiss Federal Research Institute WSL and the Swiss Forest Agency (Buwal) undersigned an agreement for the continuation of the programme «Forest Monitoring in Switzerland». The aim of this programme is to determine the present condition and to forecast the long-term development of forests in Switzerland, to analyse the dangers to which they are exposed and the causes thereof, to estimate future hazards and to deduce the implications not only for sustained management but also for forest and environmental policies. The study programme will take into account the well-established National Inventory, for which the content and methodology for the third survey are already under way; the annual Sanasilva surveys in Europe, the Plant Health Observation Service,the long-term forest ecosystem research programme on long-term observation areas and, what is new, the sub-programmes«Soil» and «Biodiversity», two very important and problematic fields, which deserve much more attention in future.

Einfluss freilebender Wiederkäuer auf die Verjüngung des Schweizer Waldes | Influence of Wild-Living Ruminants on the Regeneration of the Swiss Forest

Former, mostly authoritative knowledge on the obstruction of forest regeneration through wild-living ruminants is presently replaced by figures from numerous inventories on browsing and juvenile forest in Switzerland. In practice, the percentage of browsing has shown to be an apt indicator of the level of game damage. Thus, a more objective and differentiated picture of the situation can be presented today. On the whole, the game damage to the regeneration of the Swiss forest has not diminished during the past 25 years. However, a certain prosiness has occurred with regard to evaluation. In the Swiss Central Plateau, solutions for these conflicts have been found in the meantime. Within the alpine areas, some particularly serious cases of game damage in the forest were solved by means of problem-oriented killing-off and habitat improvements. Locally, the spread of the lynx has had its positive effects. The regeneration of the fir is a particularly significant problem. In many areas, without technical protective measures the fir has not been able to regenerate itself for decades.

Evaluating timescales of carbon turnover in temperate forest soils with radiocarbon data

Timescales of soil organic carbon (SOC) turnover in forests were investigated with soil radiocarbon data. The 12C/14C ratios were measured by accelerated mass spectroscopy on soil sampled from a deciduous temperate forest in Switzerland during 1969–1995. The resulting Δ14C values (125–174‰) were in line with previously published 14C soil data. We applied FORCLIM–D, a model of nonliving organic matter decomposition including nine litter and two soil compartments to estimate SOC turnover times for this forest type. Carbon 14 aging in woody vegetation was explicitly accounted for. Parameters were calibrated to match radiocarbon ratios observed for forest soils at Meathop Wood, United Kingdom [Harkness et al., 1986]. We estimated that roughly 50–94% (best estimate, 49%) of foliar litter carbon and 11–74% (73%) of fine root litter carbon are eventually respired as CO2 at Meathop Wood; the rest is transferred to soil humus, where it undergoes further decomposition. Turnover times for the 0–20 cm mineral soil layer ranged from 9–50 years (25 years) for a fast overturning soil compartment comprising 38–74% (68%) of bulk SOC and 155–10,018 years (3,570 years) for a slowly overturning compartment. For the Swiss site, SOC turnover times were in the same range. Parameter uncertainties were correlated and induced by uncertainties in 14C observations from small‐scale spatial inhomogeneities, sample preparation and by lack of reliable 14C observations for the “prebomb” test period. Model‐based estimates of soil organic C turnover derived from 14C data must be used cautiously since they depend on the underlying model structure: bypassing litter in FORCLIM‐D overestimated SOC turnover by a factor of 2.5. Such an error might remain undetected in studies lacking samples from the late 1960s and early 1970s. Thus litter C turnover should be included when estimating SOC turnover in temperate forests from 14C data.

Observation and Confirmation of Foliar Ozone Symptoms of Native Plant Species of Switzerland and Southern Spain

Tropospheric ozone is considered as the major pollutant of concern to the health and productivity of forests in the eastern United States and has more recently become of increasing concern within the forests of southern Europe. Recent observations have clearly demonstrated foliar injury symptoms to be occurring on many tree and native plant species within remote forested areas. Several plant genera (and a few species within genera) found in both the forests of Switzerland and the southern coastal region of Spain exhibit field symptoms typical of ambient ozone exposures. Ozone exposures for many species have been conducted under controlled CSTR conditions and within open-top chambers within the study areas. Results have confirmed that the O3-like foliar symptoms as observed under natural forest and open grown conditions for many native tree, shrub, and herbaceous species in Spain and Switzerland are caused by exposures to ambient O3.

Estimates of monoterpene and isoprene emissions from the forests in Switzerland

Emission rates of biogenic volatile organic compounds emitted by the forests were estimated for five geographical regions as well as for all Switzerland. Monoterpene and isoprene emissions rates were calculated for each main tree species separately using the relevant parameters such as temperature, light intensity and leaf biomass density. Biogenic emissions from the forests were found to be about 23% of the total annual VOC emissions (anthropogenic and biogenic) in Switzerland. The highest emissions are in July and lowest in January. Calculations showed that the coniferous trees are the main sources of the biogenic emissions. The major contribution comes from the Norway spruce (picea abies) forests due to their abundance and high leaf biomass density. Although broad-leaved forests cover 27% of all the forests in Switzerland, their contribution to the biogenic emissions is only 3%. Monoterpenes are the main species emitted, whereas only 3% is released as isoprene. The highest emission rates of biogenic VOC are estimated to be in the region of the Alps which has the largest forest coverage in Switzerland and the major part of these forests consists of Norway spruce. The total annual biogenic VOC emission rate of 87 ktonnes y−1 coming from the forests is significantly higher than those from other studies where calculations were carried out by classifying the forests as deciduous and coniferous. The difference is attributed to the high leaf biomass densities of Norway spruce and fir (abies alba) trees which have a strong effect on the results when speciation of trees is taken into account. Besides the annual rate, emission rates were calculated for a specific period during July 4–6, 1991 when a photochemical smog episode was investigated in the Swiss field experiment POLLUMET. Emission rates estimated for that period agree well with those calculated for July using the average temperatures over the last 10 years.

The winterstorm ?Vivian? of 27 February 1990: About the meteorological development, wind forces and damage situation in the forests of Switzerland

During the months January and February 1990 a series of severe cyclones were responsible for enormous wind-induced damage in Europe. The final of this series, on 27 February 1990, cyclone “Vivian” mainly affected the alpine valleys of Switzerland. 5 Millions m3 of timber were felled by the severe winds, a record number in this century. A complete damage survey of the deforested areas offers in combination with meteorological data an unique data set for a detailed case study of this extreme event.

Ectomycorrhizal syntheses with Picea abies and three fungal species: a case study on the use of an in vitro technique to identify naturally occurring ectomycorrhizae

Ectomycorrhizal syntheses between Picea abies and the fungal associates Scleroderma citrinum, Boletus luridus, and Tricholoma vaccinum were carried out using Melin's Erlenmeyer flask technique. The symbioses of S. citrinum were characterized by a mantle composed of an outer prosenchymatous and an inner synenchymatous layer. The mantles of B. luridus and T. vaccinum were solely prosenchymatous. Rhizomorphs were produced in all treatments, but only in association with S. citrinum were they differentiated with additional, enlarged hyphae. All synthesized ectomycorrhizae were white or whitish to light orange and greyishorange. On large-scale root sampling in two differing Picea abies forests in Switzerland, nine out of a total of 22 morphological types of ectomycorrhizae were white or yellow in colour and were, therefore, comparable with the synthesized ectomycorrhizae. These nine natural types generally had distinct mantle features (irregular synenchyma, gelatinous matrix, cystides, thick-walled hyphae), but mostly lacked clamp connections. Synthesized ectomycorrhizae, on the other hand, lacked distinct mantle characteristics and always had clamp connections. Natural and synthesized white or yellow ectomycorrhizae did not coincide morphologically and thus identification of the fungal partners of natural symbioses by means of in vitro-synthesis with potential ectomycorrhizal fungi was not possible in the present study.

Effect of pedestrian activity on earthworm populations of two forests in Switzerland

The effect of pedestrian activity on earthworm populations was investigated in two forests in a periurban region. In the first case, a deciduous forest, pedestrian activity affects a 2 m wide path. Simultaneous sampling with the formalin method in trodden and non-trodden soils revealed that pedestrian activity paradoxically increased total earthworm density and biomass, but reduced diversity. The mechanical and quite rapid mixing of litter into the top soil by pedestrian activity drastically decreased the presence of epigeic earthworms. At the same time, one anecique species and, to a lesser extent, one endogeic species flourished. Absence of epigeic competition and better conditions for the juveniles of the anecique species may explain this difference. The second forest, at higher altitude, is characterized by an important presence of coniferous trees. The trodden surface was investigated much larger than in the first case and pedestrian activity was more important than in the first case. It was found that the earthworm population almost totally disappeared in the trodden soil. The principal reason for this drastic reduction must be the absence of undergrowth and a litter composed mostly of coniferous needles. In conclusion, if pedestrian activity is relatively light and does not much modify the composition of the litter mixed into the top soil, it may significantly increase the density and the biomass of some anecique and endogeic species, while decreasing those of epigeic species. If pedestrian activity is important and coniferous trees are present, the earthworm population decreases drastically.

New developments in pesticides for IPM in Africa with special reference to cotton pests

There is a large knowledge base available worldwide for growing many crops according to the principles of integrated pest management (IPM). CIBA-GEIGY is active in much IPM related research. Several biological control projects are being carried out at present and include studies of Trichogramma minutum against the spruce budworm in Canada; Encarsia sp. against glasshouse white-flies in Spain; the fungus Beauveria brongniartii against cockchafers in fruit gardens and forests of Switzerland and Italy; and the protozoan (Nosema) preparations against the African desert locust. In cotton, CIBA-GEIGY is concentrating on testing pesticides for the selectivity of beneficial arthropods under practical field conditions.Some of the most important pests in cotton, rice and vegetables are monitored regularly for the occurrence of resistance, and strategies are being developed to overcome it. A computer model has been developed for American cotton, which is now under practical evaluation and which should allow for appropriate treatment decisions based on plant phenology and regular pest scouting.General recommendations are given as to the implementation of IPM programmes in cotton, which are based on methodologically sound monitoring of cotton arthropods, establishment of economic thresholds, use of selective compounds or the selective use of broad spectrum pesticides, rotation of pesticides of different chemical classes to avoid the build-up of resistance, and a strengthened search for biological control alternatives such as more potent strains of Bacillus thuringiensis.

Deposition of 134,137Cs from Chernobyl fallout on Norway spruce and forest soil and its incorporation into spruce twigs

The aims of the present research are to describe the amounts, and the variation with time, of 134Cs and 137Cs in spruce-twigs ( P. abies karst.) and in the soil of a spruce forest in Switzerland following deposition of the Chernobyl fallout. The activity of the twigs was subdivided into 3 compartments: the activity on their surfaces (i.e. the activity which can be removed from the twigs along with their natural wax coating), the activity incorporated into the needles and, finally, the activity incorporated into the wood. These compartments were separately sampled 6 times over a period from 54 to 233 days after the Chernobyl incident. Twigs which sprouted in two successive years (1985, 1986) were sampled and were found to show different behaviours. The activities associated with the 1986 twigs were roughly constant with time, while those of the 1985 twigs decreased exponentially, with half-lives around 150 days. The mean activity associated with 1 g (dry) of 1985 twigs is 724 mBq 137Cs g −1, of which 58% is incorporated into the twig wood, 17% into the needles and 25% associated with the adhering aerosol. 137Cs on the surface of the needles was found to be water-insoluble. It is believed to be strongly adsorbed on to the soil-derived fraction of the aerosol residing on the needle surface and thus provides a tracer for studying the behaviour of natural aerosols on such surfaces. The same soil profile was measured before and after the Chernobyl incident, allowing direct comparison between nuclear weapons and Chernobyl fallout. The latter is mainly (56%) stored in the litter layer, with only 4% below a depth of 13 cm; it has penetrated into the soil to a much lesser extent than weapons fallout. The forest soil inventory of 137Cs showed 2600 Bq m −2 from nuclear weapons fallout and 6200 Bq m −2 from Chernobyl. The 134Cs/ 137Cs activity ratio of the Chernobyl fallout was found to be 0·58 ± 0·01; the activity ratios in the different compartments investigated prove that incorporation of Cs into spruce occurred exclusively by uptake through the needles. A rough estimate indicates that in a spruce forest the activity stored in the twigs is half that stored in the soil.

Visit to the Forests of Switzerland

Visit to the Forests of Switzerland