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This paper presents the effects of a landslide on vegetation located on Tymfristos mountain and more specifically in the basin of the Kati stream, Sperchios river. The landslide areas are described and related to the density and the type of vegetation. The woody vegetation developed on the gliding surface was studied using dendrogeomorphologjcal methods. In particular, the direction and tilting degree of trees as well as the deformation of trunks was compared to trees growing on a neighbouring stable surface. Subsequently, the time of mass movement reactivation was estimated using a visual growth anomaly analysis on dominant fir ( Mattf.) individuals growing on the landslide. From the results it is suggested that the landslide negatively affected fir growth ring width increase at certain times without, however, nullifying it. Certain time periods are identified with intense past sliding phenomena due to increased rainfall that subsequently increased underground water.

Latium, like most other Italian regions, is subject to numerous landslides and gravitational movements. These landslides have been registered and mapped by the Region of Latium. Sixteen sites were chosen for the monitoring of ground bio-engineering projects which are currently being carried out in collaboration between the Region of Latium and the GEMINI Department of the Tuscia-Viterbo University. The monitoring activity was performed by completing a questionnaire for each site. The main data required, in order to have a complete vision of the site and its problems, concerned descriptions of the morphological, lithological and phytoclimatic aspects of the slope. This information was provided by the planners and contractors, who also gave a description of the ground bio-engineering techniques used to stabilize landslides. The aim of this study was to verify the effectiveness of using ground bio-engineering techniques in the Mediterranean climatic zone. In this zone, rooting of plants is especially complicated, but we can exploit the biotechnical characteristics of plants and adapt ground bio-engineering methods to this area. We can use information from this study to protect the territory, whilst minimizing the environmental impact, thus fostering and protecting the environment in areas where ground bio-engineering is carried out.

The L. woodlands of South Portugal are subjected to numerous attempts of reassessment, in order to control their invasion by shrub vegetation and to prevent fires. Following the intensive soil management techniques, soil is traditionally harrowed in order to establish fodder species, increase aeration and destroy shrubs and other weeds. These practices leave it bare and exposed to erosion for long periods resulting in a poor clay schist soil. In this study, the risk of erosion on woodland with different vegetation management techniques was examined. The different blocks were: shrub vegetation left undisturbed for at least 11 years, vegetation destroyed by a rotary cutter mower and enrichment with fast growing herbaceous species after tillage. To estimate soil degradation, several soil physical and chemical properties were studied. Graphical interpretation of these soil properties was performed using geostatistics. Ordinary kriging was the geostatistical technique used for the creation of maps, which were then introduced into a geographic information system (GIS) and their values reclassified. Spatial modelling was then applied using the revised universal soil loss equation and the superimposed maps developed a final overlay map for potential soil erosion. On the superimposed final map of erosion risk, the areas with highest risk of erosion were located. In those areas, the erosion risk could be decreased by suggesting simple changes in the vegetation management such as: keeping tillage only in the lowest erosion risk areas and leaving natural vegetation or enriching the soil with fast growing herbaceous species in high-erosion risk areas. The present research shows that geostatistics are useful for sustainable management of extensive agrosilvopastoral woodlands.

This manuscript describes the development and application of a fuzzy computer system for the estimation of a longterm unique torrential risk index, expressing as many parameters as possible. This paper describes the estimation of the torrential risk in the areas of Trixonida and Lisimaxia lakes and it is a part of a bigger project for the torrential risk evaluation of the watersheds, lakes and streams of Greece. The model that was introduced to the computer system works as follows: many torrential (morphometric and hydrographic) parameters are used as input to the System and they are evaluated by Fuzzy functions. This produces separate risk indices with each one associated to a specific parameter. Finally T-Norms are applied in order to unify the risk indices and to produce a unified means of risk measure. The computer system has proven its ability to work more effectively compared to the older (established) methods. From these points of view, this work can be considered as an original and important contribution in the international literature. There are no restrictions in the application-area of the system.

The creation of the National Cadastre’s map, part of which is the forest cadastre (according to the decision of the Ministry of Agriculture No 99580/506 from 1 July 1999), is based on law 266/1998 ‘National Cadastre and other provisions’ and forecasts the use of photogrammetric methods. The changes in land use, and the stretches of mountainous and semi-mountainous abandoned land are represented on these maps. The photogrammetric community is experiencing a transitional period from the analytical to the digital era. This transition is met with prudent enthusiasm, and care as to which digital systems may replace the analytical ones and under what circumstances this change will take place. This paper endeavours to answer such a question. A complete and fully documented answer lies of course, outside the limitations of this project. Here, however, a comparison was attempted between a contemporary analytical photogrammetric instrument and a digital photogrammetic system, which are both of relatively low cost. This choice was made in order to enable the market in this country to assess the limitations and possibilities of such systems, in view of the large-scale cadastral surveys. Therefore, this comparison is not only confined to accuracy, but touches upon other issues, such as reliability, user friendliness and efficiency. There are many factors, not to mention errors, in the photogrammetric procedure. There main causes are the operator, the instrumentation used and various unpredictable factors. The area of study and stereopairs thatwere usedwere chosen so that a reliable terrestrial survey would be available for the purposes of control. A rural forest area and a forest area of Taxiarchi–Vrastamon were selected. For these areas, stereopairs and related diapositives were available at the scale of 1: 20000. They were taken from an E.E.C. GR80-3 (c = 152.25 mm) aerial survey camera with an overlap of 65%. The same control points were used for the orientations on both the analytical low cost system and the digital low cost system. The analytical low cost system is a more reliable instrument than the digital low cost system, because both its repeatability and accuracy are better.

Vegetation is widely used for the control of surface erosion on slopes but different vegetation types vary in their effectiveness and, in some situations, a vegetation cover can have adverse effects and actually increase the rate of erosion. Where climatic or soil constraints exist, there are also concerns about how quickly an effective cover can be obtained. Simple screening models can be used to indicate the likely severity of these issues prior to designing an erosion-control system. As soon as the canopy cover is higher than 0.3 m above the surface, there is a risk that satisfactory protection against soil particle detachment by raindrop impact will not be obtained. With canopies higher than 1.0 m, detachment rates may exceed those from natural rainfall on bare ground. The amount of vegetation needed to prevent soil particle detachment by surface runoff depends upon the steepness of the slope but, for grasses, a stem density of at least 10,000 stems/m is recommended. Uniformity of distribution is important because a clumpy vegetation cover can lead to concentrations of flow between the plants with consequent increases in velocity. A vegetation cover can be used to induce sediment deposition. Where grass is used as a buffer strip, a width of 10–12 m is usually sufficient to trap even the fine sediment. For large areas of the world where water erosion is a problem, it is feasible to establish sufficient grass cover within 1 year.

The effect of land abandonment as a result of changing land-use policies is becoming more and more important throughout Europe. In this case study, the role of vegetation succession and landslide activity on steep abandoned slopes was investigated. The influence of vegetation succession on soil properties over time, as well as how developing root systems affect soil reinforcement was determined. The study was carried out in the Alcoy basin in SE Spain, where the marl substratum is prone to landsliding along steep ravines. The bench-terraced slopes have been abandoned progressively over the last 50 years and show various stages of revegetation. The study was carried out at two scales; at the catchment scale long-term evolution of land-use, vegetation succession and slope failure processes were investigated. At a more detailed scale, vegetation cover, soil properties and rooting effects on soil strength were determined.

The long-term performance of soil bioengineering stabilisation methods in torrent catchment areas is difficult to assess due to their dependence on site-specific factors and the interaction between those factors. In order to gain an insight into the dynamic processes of artificially initialised stands and their protection potential, case studies on hedge brush layers and live crib walls aged up to 60 years were carried out. Both construction types were traditional soil bioengineering methods using rooted plants and live plant material for stabilising and revegetation purposes. The plants were horizontally embedded between layers of fill or slope material. Live crib walls additionally included a box-like arranged timber construction which provides further mechanical stability.

Current erosion-control studies in mountainous catchments emphasise the effectiveness of bioengineering works in constructing vegetation barriers that are designed to trap and permanently retain sediment upstream of such barriers. Plant establishment and succession should result in colonisation of these sediment deposits, thereby improving the trapping capacity of the works. The aim of this study is to evaluate the ability of the natural vegetation to colonise and grow on sediment accumulated upstream of 29 bioengineering works. They were constructed on the channel bottom of two marly gullies in the mountainous Southern French Alps region, which has a Mediterranean climate. We analysed the soil seed bank in sediment deposits after a germination experiment conducted in the laboratory, where soil cores were placed in a non-limited water condition. We also determined the standing vegetation which developed on the sediment deposits on field sites over 2 years of drought (2003 and 2004). The results show that the number of plants was 80/m on average in the samples studied in the laboratory, vs. 31/m in 2003 and 20/m in 2004 on the field sites, with a total diversity of 40 species. Therefore, despite 2 years of drought, natural plant colonisation occurred on the sediment deposits. An improvement in soil water conditions slightly increases the capacity of the sediment deposits to allow seed germination. However, despite the initial success in vegetation colonisation, plant abundance and recovery were rather low, which suggests that vegetation established itself very slowly.

Soil bioengineering is an appropriate approach to deal with erosion problems and shallowseated landslides especially in developing countries such as Nepal. This technique is a cost-effective solution using locally available materials and low-cost labour. Furthermore, this approach allows the involvement of the local population in the management and maintenance aspects. As an example for prevention of soil erosion and increased slope stability by means of vegetation, a landslide in the Middle Mountains of Nepal was selected for an innovative approach of rescheduling the implementation of soil bioengineering stabilisation works into the dry, winter season, testing plants for their suitability and using cut bamboo ( G. C. Wall.) for the construction of vegetated crib walls. This paper deals with investigation, design, construction and monitoring over a period of 32 months. Soil bioengineering solutions for erosion control and shallow slope instabilities in the Middle Mountains proved to be highly successful and all plants, in particular Roxb. and Don., seemed to be suitable for winter plantation.