The following definitions should be seen as proposals. They will be further developed within ProAlp.
Alpine space (Alpenraum, espace alpin, Alpski prostor)
The alpine space defined by Bätzing for the „alpine convention“ encloses very well those regions, which would commonly be designated as alpine space and in which most of the concerned natural hazard processes take place (see also:
http://www.conventionalpine.org/page1_en.htm)
Figure I-1: Map of the area of Cooperation of INTERREG IIB – Alpine Space 2000 – 2006 and Alpine space according to the Alpine Convention (SIR, Salzburger Institut für Raumordnung und Wohnen). A Shape of the Convention Space is under construction.
Forest with protective function (Schutzwald, forêt protectrice, varovalni gozd)
Forest with protective function:
Forest with protective function in common is a forest which protects people or asset against the negative impact of environmental influences (natural hazards and civilization dangers). A specific type of the forest with protective function is the natural hazard forest with protec- tive function. The primary management objective of such forests is to maintain the protective function as their most important spatial function, timber production comes second.
The protective function of forests can be necessary on woodless areas too. Hence, the pro- tective function can also be a spatial function (the main function) of forest on a temporarily unstocked but potentially forest covered area.
The protective function implies that there is (1) a natural hazard potential, (2) a damage potential, and (3) a wooded or potentially forest covered area in between that is able to provide effective protection (a potential contribution to protect) against the natural hazard at the site (see Brang et al., 2001; cf. Fig. 1), (cited from Wehrli et al., 2007, submitted). The term forest with protective effect refers exclusively to wooded areas with protective function.
Forest with protective function may be classified into forests offering direct and indirect pro- tection (cf. Brang et al. 2006).
Forests with direct protective function can be assigned directly and definitely at local level to certain external assets (cf. Perzl 2007). A given forest provides direct protection if the protec- tive function depends on the presence of the forest at a particular location, e.g. in case of a forest that protects a village against snow avalanches.
The protective function of forests with indirect protective function cannot be assigned to cer- tain external assets clearly. Indirect protection depends on the presence of a certain propor- tion of forest at the landscape level as well as on the presence of forests at special (sensitive) sites of landscape (catchments) respectively on spatial distribution of forests within land- scapes and on average forest health. This makes it difficult to relate such forests to a certain damage potential. Examples include forests in catchment areas that potentially reduce soil erosion or peak flows (Hamilton, 1992).
Forest (Wald, forêt, gozd):
Area belonging to the land cover/use class “forest” according to national forest law definition (main input criteria: size, canopy coverage, minimal width, tree species etc.).
Asset (Schutzgut, -, dobrina):
Spatial unit that has to be protected against dangerous external processes on account of the importance of its spatial function for human existence purposes (residential, social and eco- nomic purposes). Besides that, not only material values but human resources are linked di- rectly to these spatial units.
Natural hazard (Naturgefahr, danger naturel, naravne nevarnosti):
Natural hazard (Kienholz et al. 1998):
Natural hazards are a form a dangerous process in the nature objectively menacing evil. That includes all processes and influence in the nature which can harm persons and/or tan- gible assets.
Natural hazard in specific:
Danger resulting from geomorphologic and/or meteorological processes. In the context of ProAlp, only important natural hazard - caused by gravitational forces - are included in the alpine area:
• Avalanches (Lawinen, avalanches, snežni plaz),
• Rockfall (Steinschlag, chute de pierre, padanje kamenja), • Erosion (Erosion, erosion, erozija),
• Landslide (Hangrutsch, glissement, zemeljski plaz),
• Debris flow (Murgang, laves torrentielles, hudourniški nanos) and • Floods (Überschwemmung, inundation, poplava).
These hazards are also known as “gravitational natural hazards” (gravitative Naturgefahren, dangers naturels gravitationnels).
Civilization danger (Zivilisationsgefahr, -, civilna nevarnost):
Materials and processes caused directly by human residential and economic activities, which are harmful to people and material goods e.g. smog, noise or light pollution caused by traffic. Civilization dangers are not taken into consideration at ProAlp.
Natural hazard potential/area of natural hazard process (Naturgefahrenpotenzial, po- tentielle de dangers/aléas naturels, nevarnost naravnih nesreč/potencialno območje naravnih nesreč)
The natural hazard potential indicates where a natural hazard can occur potentially and how far its impact may reach. Besides, the protective effect of existing stockings is not taken into consideration. The danger potential describes spatially the frequency and intensity of natural hazards processes to be expected. The result is a modelled susceptibility and impact area of natural hazard processes, which can be separated in 3 zones:
- Starting zone (Startgebiet), called release area (Anrissgebiet, Anbruchgebiet) in the case of avalanches and landslides,
- Transit zone (Transitgebiet), the fall track, where the masses move without deposition due to the topography.
- Run-out zone (Auslauf- und Ablagerungsgebiet), where the masses are stopped and de- posited due to the topography.
The natural hazard potential results from the analysis of the potential natural hazards (sus- ceptibility for hazard release), the analysis of the dynamic and the impacts of natural hazard
Damage potential ≈ potentially endangered objects (Schadenpotenzial ≈ potentiell ge- fährdete Objekte, dégats potentials ≈ objets menacé)
The possible degree of damage to people and asset endangered (see Kienholz et al. 1998). In ProAlp the damage potential is a function of the value, of the vulnerability and the pres- ence likelihood of the endangered asset (simplified explanation).
Protective effect (Schutzwirkung, effet protectrice, zaščitni učinek)
A) The protective effect by forests in the meaning of the effect mechanism (totality of the ef- fective processes like interception, transpiration, soil stabilization, mechanical resistance, friction etc.). By contrast the term "protective function" means the protecting task of forest in the spatial planning context assigned by society.
B) The magnitude of protecting effects of these effect mechanisms. The protective effect of a forest strongly depends on the hazard type and can have different aspects, i.e., prevention or mitigation of natural hazards. According to hazard type a different potential contribution of forests to the protection is possible. For snow avalanches, for instance, the protective effect of a forest is rather preventive than mitigating (Margreth 2004). For single rockfall events, tree stems and even dead trees lying on the ground allow to effectively mitigate the hazard by slowing down or even stopping the falling rocks (Dorren et al. 2005). However, forest can- not prevent the release of rockfall completely, but could even cause rockfall release. Tree roots reduce shallow landslide hazard by mechanical reinforcement of the soil (Hamilton 1992, Rickli et al., 2001). Tree roots can also increase the soil volume available for water storage, in particular on soils with moderate permeability (Hegg et al., 2005). Additional ef- fects of forests on erosion and hydrological processes include e.g., the permanent input of litter reducing surface erosion and increasing the water-holding capacity of the soil by build- ing-up an organic layer (cf. Hamilton, 1992) or the influence on interception and evapotran- spiration leading to an improved water balance of the soil (Rickli et al., 2004, Frehner et al., 2005)
Susceptibility (Disposition, -, občutljivost)
Tendency of a certain area to trigger dangerous processes. Kienholz et al. (1998) defines two different types:
Basic susceptibility: Permanent or long time tendency or readiness to (dangerous) proc- esses.
Variable susceptibility: Temporally fluctuating tendency or readiness to (dangerous) proc- esses due to changing site parameters.
Vulnerability (Vulnerabilität = Verwundbarkeit, Verletzlichkeit, ranljivost):
The quality magnitude of an object (asset) regarding its resistance against being damaged. For example, two objects (assets) of the same monetary value or with the same space- functional importance can be vulnerable differently (e.g. a single family dwelling made from wood or made from concrete).
Risk analysis (Risikoanalyse, analyse des risques, analiza tveganja)
Detailed examination including risk assessment, risk evaluation and risk management alter- natives, performed to understand the nature of unwanted, negative consequences to human life, health, property or environment; analytical process to provide information regarding un- desirable events; the process of quantification of the probabilities and expected conse- quences for identified risks (source: Glossary of the Society of Risk Analysis:
http://www.sra.org/resources_glossary_p-r.php).
In the context of natural hazards, the risk analysis consists in
• Analysis of the potential natural hazards (Gefahrenidentifikation, Dispositionsanalyse, Ereignisanalyse).
• Analysis of the dynamic and the impacts of a natural hazards process (Wirkungsana- lyse).
• Analysis of the potential damage at people/settlements and assets/infrastructure re- spectively and analysis of affected assets by natural hazards (Expositionsanalyse). • Analysis of the consequences of a possible natural hazard for the endangered ob-
jects (Folgenanalyse, Risikoanalyse bei gravitativen Naturgefahren. Umwelt- Materialien Nr. 107/I. BUWAL (Hrsg.), Bern, 1999).
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