Berichte WSL, No. 327-347 (1990-1999)

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Abstracts

Gallenmüller, F.; Bogenrieder, A.; Speck, Th., 1999:
Biomechanische und ökologische Untersuchungen an Alnus viridis (Chaix) DC. in verschiedenen Höhenlagen der Schweizer Alpen.
Zusammenfassung, Résumé Riassunto, Summary, Ill.

ISSN 1016-3166
ISBN 3-905620-75-8
Price CHF 9.40

Biomechanical and ecological studies on Alnus viridis (Chaix) DC. from different altitudes in the Swiss Alps In order to characterise the effect of different climatic conditions on the growth of Alnus viridis, investigations on growth-morphology, tissue-distribution, width of annual rings, wood anatomy and seed weight as well as germination experiments were carried out for four stands at different altitudes in the Swiss Alps. The mechanical properties of the stems of Alnus viridis were characterised in bending experiments, measuring bending stiffness and structural Young’s modulus. The results of these experiments correlate with the results of the studies of stem anatomy.
The results of the bending experiments and of the analysis of stem anatomy obtained for the different stands in the Alps were compared to each other, and to already available data for the Alnus viridis-population in the Black Forest. The comparisons show that in the Black Forest a clan with stems with greater bending stiffness exists. In contrast, the differences found between the different stands in the Alps, which are due to the influence of different site conditions, are much less pronounced.
Keywords: Alnus viridis, annual ring width, seed weight, germination experiments, stem anatomy, bending stiffness, Young’s modulus, Swiss Alps, Black Forest

Röthlisberger, G., 1998:
Unwetterschäden in der Schweiz. Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 346: 51 S.
Zusammenfassung, Résumé, Riassunto, Summary, Ill.

ISSN 1016-3166
ISBN 3-905620-69-3
Price CHF 14.-

Weather Damage in Switzerland

Statistics on damage due to floods, landslides and debris flows for the 25 years 1972-1996 are given. The extent, severity and causes of the events are examined, as well as the seasonal and spatial distribution of the costs.
In the second section weather-linked disasters of present times are compared with those of the past, and a possible relationship between climatic fluctuations and extreme flood events is sought. Examples illustrate the reasons for the ever increasing costs of damage. A review of climate and weather in earlier centuries is given. The report closes with a discussion of the influence of forest in flood protection.

Keywords: weather damage, damage costs, floods, landslides, flood disasters, climatic influences

Brang, P. (Red.) 1998:
Sanasilva-Bericht 1997. Zustand und Gefährdung des Schweizer Waldes - eine Zwischenbilanz nach 15 Jahren Waldschadenforschung. Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 345: 102 S.
Zusammenfassung, Résumé, Riassunto, Ill.

ISSN 1016-3166
ISBN 3-905620-67-7
Price: CHF 21.-
Abstracts are available in the following languages: Deutsch, English, Français

Sanasilva-Report 1997. Swiss forests: Their condition and potential threats. An interim assessment after 15 years of research on forest damage.

Deposition of atmospheric pollutants represents a long-term risk for Swiss forests. However, there are no indications that their existence is threatened in the short term. This evaluation is based on many individual studies and on the results of the Sanasilva inventory.
The condition of trees in Swiss forests is assessed in a representative way by the Sanasilva inventory. Between 1985 and 1997, the proportion of trees assessed as having crowns with more than 25% defoliation due to unknown causes rose from 8 to 17%. The annual mortality rate has remained at about 0.4%, which is not considered to be exceptional.
There are many potential natural and anthropogenic causes for the increase in crown defoliation. As these all act simultaneously on the forest, it is not possible to identify single factors as being responsible. Possibilities include the gradual ageing of the Swiss tree population, droughts, the Vivian storm of 1990 and air pollutants. The investigations that have been done so far have given very little indication of the extent of the relationship between air pollution and crown defoliation. An exception is the presence of visible injury to the foliage of sensitive plants caused by the very high levels of ozone in south Ticino.
Crown defoliation has only a limited value as an indicator of the vitality of trees. Differences in crown defoliation are for example caused by differences in site conditions. It is therefore difficult to interpret the observed increase in defoliation. It is possible that the changes indicate an increase in the stress experienced by trees.
Air pollution, in the form of acidic deposition and nitrogen deposition, represents a long-term risk as it can result in soil acidification, nutrient leaching and nutrient imbalances. These changes could cause adverse effects for acidic soils within a few decades. Critical loads for acids and nitrogen and critical levels for ozone, as determined by international agreement, are exceeded for many Swiss forests. Under the precautionary principle, air pollution should be reduced so that these levels and loads are no longer exceeded.
The impact of air pollutants on forests, and the speed of undesirable developments and recovery processes are complex issues and need further study. A priority is the development of alternative indicators of forest health that have greater value than crown defoliation. In order to answer these questions, the Swiss Government is undertaking multi-disciplinary, long-term studies of the forest through its «Long-Term Forest Ecosystem Research Project», which is a part of the «Swiss Forest Observation Programme».

Keywords:
forest condition, forest ecosystem health, inventory, defoliation, Picea abies, Abies alba, Fagus sylvatica, forest decline, forest pests, ozone, climatic change, air pollution, critical levels, critical loads, soil acidification, Switzerland

Stepien, E.; Gadola, C.; Lenz, O.; Schär, E.; Schmid-Haas, P., 1998:
Die Taxierung der Holzqualität am stehenden Baum.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 344: 68 S.

ISSN 1016-3166
ISBN 3-905620-63-4
Price: CHF 17.-

Assessment of timber quality on the stump

This study examines how the quality of the sawn timber of five tree species, namely spruce (Picea abies), fir (Abies alba), pine (Pinus sylvestris), larch (Larix decidua) and beech (Fagus sylvatica) depends on the visible characteristics of the standing timber, and to what degree the quality of the rough timber can be made on the basis of various characteristics (from a combination of individual characteristics with multiple regression, taxation according to the First Swiss Forest Inventory basic principles of forest growth and the guidelines laid down by the "Schweiz. Holzhandels-Gebräuche" for standing and felled timber).
Due to the large number of trees examined the relationships between the visible characteristics of the standing tree and the timber quality are mostly statistically significant, though the correlation coefficients are small. This is due to the great natural variability of tree characteristics which cannot be adequately assessed from one parameter alone. When several features are included in one multiple regression model, the overall variability of the sawn timber quality can be reduced to about 40% for beech and spruce and 55% for fir, pine and larch. The conventional procedures for assessing the quality of standing timber are, in contrast, unsatisfactory, as they explain only 10-30% of the variability.
The evaluation shows that the conventional assessment procedures must be improved and made more efficient. A simply organised, objective and cost-efficient method was therefore elaborated.

Keywords: timber quality, forest inventory, assessment on the stump

Böll, A., 1997:
Wildbach- und Hangverbau.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 343: 123 S.
ISSN 1016-3166
ISBN 3-905620-58-8
Price: CHF 24.-

Torrent Control and Slope Stabilisation

Floods, debris flows and slope failures are among one most important natural hazards in the lower alpine regions and in the Alps. From time immemorial, they have determined the position and nature of settlements, roads, and railway lines and have influenced human activities.
Roughly, the releasing processes can be classified as those that occur in torrents and those that take place on slopes. Since torrents exert influences on adjacent slopes, and vice versa, the processes are highly complicated and interactive. In most cases, however, water is a determining factor.
Our activities consist of hazard assessment, planning, design and construction of structural and combined structural-biotechnical stabilisation measures. Whereas hazard assessment is based, to no small degree, on geology and geomorphology, in addition to engineering sciences, of course, the planning and design of structures are pure engineering topics. Sound knowledge in hydraulic engineering, soil mechanics and foundation engineering as well as structural engineering is most essential. Hazard assessment has to take all the different processes in a catchment area into consideration. It is very important as it not only gives answers to questions concerning land use, but also provides information about the general position of possible protective measures. It is therefore a prerequisite for further activities. In most cases, of course, sooner rather than later, our clients want to know relevant details about proposed structural and combined structural-biotechnical stabilisation measures.
This publication describes different problems and possible solutions from an engineer's point of view. It deals with processes in torrents and on slopes and their interaction, with critical loads on structures and the design of protective measures. It also considers the limits of technical methods in natural surroundings.

Keywords: natural hazards, torrent control, slope stabilisation, structural measures

Brändli, U.-B., 1998:
Die häufigsten Waldbäume der Schweiz. Ergebnisse aus dem Landesforstinventar 1983-85: Verbreitung, Standort und Häufigkeit von 30 Baumarten. 2. Auflage.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 342: 278 S.
ISSN 1016-3166
ISBN 3-905620-54-5
Price: CHF 38.- NEU 20.-

The commonest forest trees in Switzerland. Findings from the National Forest Inventory 1983-85: Distribution, site and frequency of 30 tree species

In 1983-85 the surveys for the first Swiss National Forest Inventory (NFI) were conducted. In 1988 the major results of this countrywide sampling survey over a 1x1 km grid were published. We now present as a supplement a detailed report, based on the results of the first NFI, on the occurrence of the 30 commonest forest tree species in Switzerland:
Picea abies (L.) Karst, Abies alba Mill., Pinus sylvestris, L. Pinus mugo Turra var. arborea Tubeuf, Pinus cembra L.,Larix decidua Mill., Taxus baccata L.,Fagus sylvatica L., Carpinus betulus L., Ostrya carpinifolia Scop.,Quercus robur L., Quercus petraea (Matt.) Liebl., Acer pseudoplatanus L., Acer platanoides L., Acer campestre L., Fraxinus excelsior L., Fraxinus ornus L., Prunus avium L., Tilia cordata Mill., Tilia platyphyllos Scop., Ulmus glabra Huds. emend. Moss., Castanea sativa Mill., Robinia pseudoacacia L.,Betula pendula Roth, Populus tremula L., Salix spec., Alnus incana (L.) Moench., Alnus glutinosa (L.) Gaertn., Sorbus aria (L.) Crantz, Sorbus aucuparia L.
As well as distribution maps, this report contains presentations on the frequency (stem count, standing volume) of the individual species together with aspects of the sites and stands: region, elevation, stage of vegetation, type of relief, exposure, inclination, diameter classes, proportion of mixture, admixed tree species, stand age, forest type, stage of development and type of regeneration.

Keywords: tree species, stem count, standing volume, distribution, site, national forest inventory, Switzerland

Erni, V.; Lemm, R., 1995:
Ein Simulationsmodell für den Forstbetrieb - Entwurf, Realisierung und Anwendung.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 341: 89 S.
Zusammenfassung, résumé, riassunto, summary. 44 Figures, 9 Tables.
ISSN 1016-3166
ISBN 3-905620-47-2
Price: CHF 26.- gratis

A Simulation Model for Forest Enterprises - Design, Realisation and Application

This report describes a dynamic, computer-assisted simulation model for planning and management tasks in Swiss forestry. The parameters duplicated are regeneration, tending, thinning, final cutting, growth, and the harvesting costs and yields from various assortments per stand. Changing environmental conditions are also taken into consideration. The functional parameters were fed into the model via ASCII files and could be modified without changing the programme. An easily applied menu and dialogue user interface is available for system steering, data registration and data output. The article gives examples of the application of the model in long- and mid-term application to forest management planning, illustrating the effects of profit and loss in a forest enterprise, quantifying the loss in value due to bark peeling damage, and finally showing how intensification of wood production can be balanced against extension in a forest enterprise. Test studies have shown that this model furnishes reliable results and can be validly applied as a basis.

Keywords: Forest enterprise, simulation, stand model, forest management planning

Frank, Carmen; Baumann, T., 1995:
"ArGo". Eine deutschsprachige Benutzeroberfläche für das Geographische Informationssystem "ArcInfo".
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 340: 27 p.
Zusammenfassung, Résumé, Riassunto, Summary. 11 Figures. ISSN 1016-3166
ISBN 3-905620-44-8
Price: CHF 18.- gratis

"Argo". A Menu-driven User Interface for Geographical Information System "ArcInfo", formulated in German

Geographical Information Systems (GIS) are employed in the processing of data on spatial distributions in universities, government offices and private concerns. GIS users unfamiliar with this tool often have initial difficulties with the application of the software, especially as the technical terms are usually given in English. To facilitate initiation into the use of ArcInfo and rationalise routine procedures, a menu-driven user interface in German has been conducted for the GIS ArcInfo^TM and PC ArcInfo^TM programmes, described in this technical report.

Keywords: Geographic Information Systems GIS, ArcInfo^TM, step-by-step menu-driven user interfaces, AML, SML, digitalisation, correction, allocation to data categories, analysis, planning, representation, map output

Innes, J.L.; Böhm, J.; Bucher, J.B.; Dobbertin, M.; Jansen, E.; Kull, P.; Rigling, A.; Walthert, L.; Zimmermann, S., 1994:
Sanasilva-Bericht 1993. Der Zustand des Schweizer Waldes.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 339: 60 p.
Zusammenfassung, Résumé, Riassunto, Summary. 39 Figures, 13 Tables.
ISSN 1016-3166
ISBN 3-905620-37-5
Price: CHF 18.- gratis

Sanasilva Report 1993. The Condition of the Swiss Forest

A consistent inventory of forest condition has been made in Switzerland since 1984. In 1993, several changes were made, including a reduction in the sample size by 75%, representing a change from a 4 x 4 km grid to an 8 km x 8 km grid. Results are now presented only for the country as a whole, for Norway spruce, silver fir and beech, and for mountain and non-mountain sites. The results suggest an increase in defoliation since 1992, but the increase was within the range of the measurement errors. The proportion of trees with more than 25% unexplained defoliation appears to have increased since 1985 and a satisfactory explanation for this has not yet been achieved. Consequently, assessments of soils, vegetation, climatic conditions and pollution levels in the plots are being made. A detailed evaluation of the quality of the data collected in the inventory has been made and the results indicate that a number of problems remain.

Keywords: forest condition, inventory, monitoring, Picea abies, Abies alba, Fagus sylvatica, mountain forests, forest diseases, forest pests, ozone, climatic influences, soil classification, vegetation classification

Scherrer, H.U.; Schmidtke, H.; Oester, B., 1994:
Folgeaufnahmen. Erfassen von Veränderungen des Waldzustandes mit Luftbildern.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 338: 47 p.
Zusammenfassung, Résumé, Riassunto, Summary. 15 Figures, 12 Tables.
ISSN 1016-3166
ISBN 3-905620-35-9
Price: CHF 24.- gratis

Subsequent inventories. Monitoring Changes in Forest Condition by Means of Aerial Photographs

The possible methods and techniques of monitoring forest condition over large areas are described and evaluated. Forest areas may alter in terms of boundaries (geometry) or in terms of condition (information). The procedure rests on infrared aerial photographs at scales of 1:5000 to 1:12 000. Inventory projects so far only internally reported on are presented. The experience gained has allowed the formulation of a comprehensive work programme "Subsequent Inventories". This takes six criteria into account: identical stand limits, retrospective interpretation, homogeneity of the stock, small-scale geometry, comparison of photos, and identity of the stock. The fields of investigation are: photogrammetry, identification of stands, interpretation, data collection and evaluation, application of GIS and mapping. "Subsequent Inventories" is feasible but much more demanding than a single inventory.

Keywords: infrared aerial photographs, forest damage inventory, recovery inventory, forest condition, monitoring, geographic information systems

Hantke, R., 1995:
Erdgeschichte des Bödmerenwaldes (Gemeinde Muotathal, Kt. Schwyz). Erläuterungen zur Geologischen Karte 1:2000. 2. überarbeitete Aufl.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 337: 32 S.
ISSN 1016-3166
ISBN 3-905620-46-4
Price: CHF 22.- gratis

Earth History of the Bödmeren Forest (Muotathal, Canton of Schwyz)
Notes on the geological map 1:2000

As part of a multidisciplinary scientific project in the Bödmeren forest a geological map of an area of 2.3 km2 was constructed on a scale of 1:2000. The area is tectonically complicated and belongs to the Helvetic Axen Nappe and the overlying Druesberg Nappe, which, on the Roggenstöckli on the eastern margin of the map, forms a klippe. In between, in dips and fracture zones of the highest tectonic element in the Axen Nappe, the Oberen Silberen scale, lies the inverted sequence of the Druesberg Nappe.
Beyond the Toralp ridge, (to the south-east of the map), where they meet the Oberen Silberen scale, they are termed the Toralp series.
The stratigraphical sequences are composed of Cretaceous sediment, mainly limestones. Tectonic studies show that both the formation of the nappe and the fractures were concurrent with the settling of the Helvetic Nappe. This occurred during the transition from the Miocene to the Pliocene, at least 5 million years ago.

Keywords: geology, tectonics, Helvetic nappes, Axen Nappe, Druesberg Nappe, karst, landscape development, Bödmeren forest, Muotathal SZ

Marti, F.; Stutz, H.-P. B., 1993:
Zur Erfolgskontrolle im Naturschutz. Literaturgrundlagen und Vorschläge für ein Rahmenkonzept.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 336: 171 p.
Zusammenfassung, Résumé, Riassunto, Summary.
ISSN 1016-3166
ISBN 3-905620-29-4
Price: CHF 28.- gratis

Checking of Success in Nature Conservation. Literary Background and Proposed Basic Concept

A basic concept for the checking of success of measures in Nature conservation, is synthesized on the basis of practical experience and recent literature in the fields of Nature conservation, land-use planning and ecology. The concept comprises execution check, attainment of aims, checking of effects and analysis of aims. Case studies show that comprehensive check systems have so far seldom been applied in Nature conservation and, together with land-use planning reveal problem areas: definition of aims, forecasts of effects, monitoring, interaction of measures. These problems are discussed in the light of recent literature. The concept comprises 11 steps and may be used as a basis for individual projects.

Keywords: execution checks, attainment checks, checking effects, goal analysis, goal definition, Nature conservation, monitoring, indicators

Conedera, M., 1993:
Cancro corticale del castagno. Principali caratteristiche epidemiologiche e misure pratiche di controllo.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 335: 40 p.
Riassunto, Zusammenfassung, Résumé, Summary. 34 Figures, 3 Tables.
ISSN 1016-3166
ISBN 3-905620-23-5
Price: CHF 26.- gratis

Chestnut blight. Symptoms and biology of the disease, and control measures

This report describes the current knowledge on chestnut blight. The history of the introduction and dispersal of the disease is shortly summarized and followed by a description of the actual disease situation in Europe with emphasis on Switzerland. The symptoms of the disease are described as well as the biology of the pathogen. The biological basis of resistance of the chestnut tree towards the pathogen and the hypovirulence is explained. The latter led to drastic reduction in disease severity and to the recovery of European chestnut stands. The phenomenon of vegetative compatibility groups of C. parasitica explains why hypovirulence has not so far spread worldwide. A key to group the different aspects of cankers is proposed. Phytosanitary methods to control the disease in orchards and sprout coppices are discussed.

Interested readers who want to study certain aspects of the chestnut blight in more detail are referred to a long list of literature citations.

Keywords: Cryphonectria parasitica, Endothia parasitica, Castanea sativa, European chestnut, disease control, biological control, chestnut orchard

Sanasilva Abschlussbericht, 1992:
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 334: 58 p.
ISSN 1016-3166
ISBN 3-905620-17-0
Price: CHF 24.- gratis

Sanasilva final report

This final report summarizes the activities undertaken within the Swiss forest damage programme "Sanasilva" between 1984 and 1991. They include annual terrestrial damage assessment (leaf and needle loss); evaluation of forest condition through infrared aerial photographs; optimization of inventory methods; the manifold activities of the Plant Health Observation and Information Service; the implementation of mobile cable cranes for logging; consultancy for technical and economic planning in forestry in mountain regions; integral planning and checks in forest enterprises; aids to silviculture in severely damaged spruce stands, such as computer programmes on planning or the dynamics of forest damage; the classification of forest gene pools; and documentation and advanced training. The aims, methods, project design, activities, and results of each sub-project are summarized, and their significance for practical forestry and research described. Publications to date are listed.

Keywords: forest damage, surveys, inventory methods, infrared aerial photographs, harvesting, integral planning, gene pools, Plant Health Observation and Information Service

Frehner, E.; Fürst, E., 1992:
Vom Samen bis zur Pflanze. Ein Erfahrungsbericht aus dem Forstgarten.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 333: 47 p.
Zusammenfassung, Résumé, Riassunto, Summary. 16 Figures, 7 Tables.
ISSN 1016-3166
ISBN 3-905620-14-6
Price: CHF 22.- gratis

From Seed to Plant. Experience in a Forest Nursery

This paper provides suggestions for work in forest nurseries. It aims at furnishing practical foresters with the results of many years' experience in forest plant production and seed trials, and deals with species selection, provenance, harvest stands and trees, seed harvesting, treatment and storage, germination tests, sowing techniques, and methods for protection and tending in the nursery. An Appendix provides information on harvesting times and methods, after-ripening and seed treatment, seed yield, thousand-seed weight, germinating capacity, storage and stratification, and seedling yield for various species.

Keywords: provenance, seed collection, seed treatment, seed storage, plant production

Wüthrich, W., 1992:
Die Feinerschliessung von Waldbeständen - Planung, Anlage und Benützung.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 332: 92 p.
Zusammenfassung, Résumé, Riassunto, Summary. 47 Figures, 14 Tables.
ISSN 1016-3166
ISBN 3-905620-11-1
Price: CHF 26.- gratis

Minor Transport Networks in Forest Stands - A Guide to Planning, Installation, and Use

This study first presents the fundamentals involved in planning and installing minor transport networks, then presents a stepwise planning procedure taking field conditions and available means into consideration, and suggests possible variants. Suitability and efficiency are priorities. The location and combination of skid trails, skid roads, and cable cranes are discussed in detail. Hints on the use and maintenance of skid trails and skid roads complete the report.

Keywords: forest, minor transport planning, logging concept, skid trails, skid roads, cable cranes

Lenz, O.; Nogler, P.; Schär, E., 1991:
L'élagage et la qualité des bois d'Epicéa (Picea abies Karst.) et de Sapin blanc (Abies alba Mill.) de peuplements réguliers du Plateau suisse.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 331: 51 p.
Résumé, Zusammenfassung, Riassunto, Summary. 21 Figures, 20 Tables.
ISSN 1016-3166
ISBN 3-905620-10-3
Price: CHF 18.- gratis

Pruning and Wood Quality in Spruce (Picea abies Karst.) and Fir (Abies alba Mill.) in Uniform Stands in the Swiss Mittelland

From 1929 to 1950 three different pruning techniques - dry pruning, slight green pruning, and heavy green pruning - were tested in uniform spruce and fir stands in the Swiss Mittelland, using ladders and fine-toothed handsaws. The trees were felled between 1973 and 1983, and the quality of the cabinet wood was assessed. Severe green pruning produced the most rapid effects and thus the greatest yield of knot-free cabinet wood. The results showed that pruning should start at an early stage, though it is only really worthwhile in flourishing stands. Under these conditions the yield of knot-free wood can reach 80-90%. A more recent trial investigated the influence of different techniques (tree pruning machine, handsaw in combination with climbing stirrups, climbing spikes, and ladders) on wood quality.

Keywords: pruning, wood quality, spruce, fir, damage, Swiss Mittelland

Röthlisberger, G., 1991:
Chronik der Unwetterschäden in der Schweiz.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 330: 122 p.
Zusammenfassung, Résumé, Riassunto, Summary. 99 Figures, 9 Tables.
ISSN 1016-3166
ISBN 3-905620-09-X
Price: CHF 26.- gratis

Chronicle of Weather Damage in Switzerland

Information on 2256 weather damage events between 563 and 1988 is given. Only damage due to thunderstorms, prolonged downpours, and snow melt is considered.

The first part describes the methods and criteria employed and gives a statistical analysis of the extent, cause, type, and seasonal distribution of the damage. A century-by-century survey records the climate, years with extreme weather conditions, and disastrous events. The second part provides a chronological description of 261 severe weather damage events. The study is supplemented by maps, illustrations, and an extensive bibliography, and ends with a discussion of costs, forecasting, and preventive measures.

Keywords: weather damage, floods, landslips, weather disasters, climatic influence, weather

Diez, C.; Bürgi, A., 1991:
Wuchsleistung und Qualität von Douglasie (Pseudotsuga menziesii [Mirbel] Franco), Riesen-Lebensbaum (Thuja plicata Donn) und Roteiche (Quercus rubra L.) in der Schweiz.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 329: 46 p.
Zusammenfassung, Résumé, Riassunto, Summary. 12 Figures, 7 Tables.
ISSN 1016-3166
ISBN 3-905620-08-1
Price: CHF 20.- gratis

Growth Production and Quality of Douglas Fir (Pseudotsuga menziesii [Mirbel] Franco), Western Red Cedar (Thuja plicata Donn) and Red Oak (Quercus rubra L.) in Switzerland

The growth production and quality of Douglas firs (Pseudotsuga menziesii), western red cedars (Thuja plicata) and red oaks (Quercus rubra) on various sites were investigated and compared with those of indigenous species. The growth production of Douglas fir and red oak was markedly better than that of spruce (Picea abies) and beech (Fagus sylvatica), while that of western red cedar was not superior to the same degree. The quality, which is greatly influenced by silvicultural treatment, was not convincingly superior in every case. If it could be improved, cultivation of Douglas fir and red oak would be a possible means of increasing the financial yield from the stands.

Keywords: cultivation of exotics, Pseudotsuga menziesii, Thuja plicata, Quercus rubra, growth production, stem quality, silviculture

Kienast, F.; Frank, Carmen; Leu, R., 1991:
Analyse raum-zeitlicher Daten mit einem Geographischen Informationssystem.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 328: 36 p.
Zusammenfassung, Résumé, Riassunto, Summary. 15 Figures, 7 Tables.
ISSN 1016-3166
ISBN 3-905620-05-7
Price: CHF 19.- gratis

Analysis of spatio-temporal data with a Geographical Information System

Two methods for analyzing spatio-temporal data by means of a Geographical Information System are presented and evaluated with numerous examples. Digitized historic topographic maps of two pilot plots in Switzerland, and a forest management plan of a community on the Swiss Plateau are used as test data. Data processing was performed on a Microvax-3600 computer (VAX/VMS) and a Tektronix-4336 workstation (UNIX) with the software ARC/INFO(c). In the first method complete maps of each time step are stored. Each layer is generated by copying and modifying the previous cover. In the second method only the first inventory is stored completely. Subsequently only the changes from one time step to the next are digitized and stored. For both methods all layers that fall within a certain time frame are merged into a composite cover. The latter consists of all line or area elements of a particular set of time steps. Each element is characterized with time-stamped attributes such as birth, death and identification. Consequently the entire life history of each element considered can be accessed from the actual cover. Thus both methods are suitable updating procedures for any inventory of landscape or forest resources.

Keywords: Geographical Information System, spatio-temporal data, historic topographic maps, forest management plans, ARC/INFO(c), landscape history, Switzerland

Bachmann, P., 1990:
Produktionssteigerung im Wald durch vermehrte Berücksichtigung des Wertzuwachses.
Ber. Eidgenöss. Forsch.anst. Wald Schnee Landsch. 327: 73 p.
Zusammenfassung, Résumé, Riassunto, Summary. 30 Figures, 21 Tables.
ISSN: 1016-3166
ISBN: 3-905620-04-9
Price: CHF 26.- gratis

Increase of Forest Production through Greater Attention to Value Increment

An automated procedure for calculating value increment based on data from the control inventory of the WSL was developed and tested in four forest enterprises. With relatively little extra work, it provides data allowing more detailed planning, especially regarding regeneration. Weak points and possibilities for improvement are discussed and concrete suggestions for the rapid practical application of the new findings are made.

Keywords: Value increment, control sample plots, regeneration, silvicultural planning