Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environments, characterized by either steep or gentle slope gradients, from mountain ranges to coastal cliffs or even underwater, in which case they are called submarine landslides. Gravity is the primary driving force for a landslide to occur, but there are other factors affecting slope stability that produce specific conditions that make a slope prone to failure. In many cases, the landslide is triggered by a specific event, although this is not always identifiable.
In the United States, national forest is a classification of protected and managed federal lands. National forests are largely forest and woodland areas owned collectively by the American people through the federal government, and managed by the United States Forest Service, a division of the United States Department of Agriculture. The U.S. Forest Service is also a forestry research organization who provides financial assistance to state and local forestry industry. As of 2020, there are 154 national forests in the United States.
Reforestation is the natural or intentional restocking of existing forests and woodlands (forestation) that have been depleted, usually through deforestation, but also after clearcutting.
An avalanche is a rapid flow of snow down a slope, such as a hill or mountain.
A geologic hazard or geohazard is an adverse geologic condition capable of causing widespread damage or loss of property and life. These hazards are geological and environmental conditions and involve long-term or short-term geological processes. Geohazards can be relatively small features, but they can also attain huge dimensions and affect local and regional socio-economics to a large extent.
A rockfall or rock-fall is a quantity/sheets of rock that has fallen freely from a cliff face. The term is also used for collapse of rock from roof or walls of mine or quarry workings. "A rockfall is a fragment of rock detached by sliding, toppling, or falling, that falls along a vertical or sub-vertical cliff, proceeds down slope by bouncing and flying along ballistic trajectories or by rolling on talus or debris slopes."
A gabion is a cage, cylinder or box filled with rocks, concrete, or sometimes sand and soil for use in civil engineering, road building, military applications and landscaping.
Aerial seeding is a technique of sowing seeds by spraying them through aerial mechanical means such as a drone, plane or helicopter. When the purpose is reforestation, it is known as aerial reforestation.
The Blons avalanches took place in Austria in January 1954. They occurred in the federal state of Vorarlberg, where they had a big impact on the Great Walser Valley region and specifically, the village of Blons. The avalanches occurred over a two-day period beginning from 11 January 1954 and resulted in the death of 125 people, 57 of whom were killed specifically in Blons. Two big avalanches struck Blons within 9 hours, the second of which buried rescue workers who were attempting to save civilians from the first avalanche. The avalanches caused much destruction to the Blons village, damaging one third of housing infrastructure and killing one third of the population. The Blons avalanches are considered to be one of the worst mass burials in Austrian history, resulting in one of the highest number of fatalities due to an avalanche.
Forest protection is a branch of forestry which is concerned with the preservation or improvement of a forest and prevention and control of damage to forest by natural or man made causes like forest fires, plant pests, and adverse climatic conditions.
Landslide mitigation refers to several man-made activities on slopes with the goal of lessening the effect of landslides. Landslides can be triggered by many, sometimes concomitant causes. In addition to shallow erosion or reduction of shear strength caused by seasonal rainfall, landslides may be triggered by anthropic activities, such as adding excessive weight above the slope, digging at mid-slope or at the foot of the slope. Often, individual phenomena join together to generate instability over time, which often does not allow a reconstruction of the evolution of a particular landslide. Therefore, landslide hazard mitigation measures are not generally classified according to the phenomenon that might cause a landslide. Instead, they are classified by the sort of slope stabilization method used:
Avalanche control or avalanche defense activities reduce the hazard avalanches pose to human life, activity, and property. Avalanche control begins with a risk assessment conducted by surveying for potential avalanche terrain by identifying geographic features such as vegetation patterns, drainages, and seasonal snow distribution that are indicative of avalanches. From the identified avalanche risks, the hazard is assessed by identifying threatened human geographic features such as roads, ski-hills, and buildings. Avalanche control programs address the avalanche hazard by formulating prevention and mitigation plans, which are then executed during the winter season. The prevention and mitigation plans combine extensive snow pack observation with three major groups of interventions: active, passive and social - sometimes more narrowly defined as "explosive", "structural", and "awareness" according to the most prevalent technique used in each. Avalanche control techniques either directly intervene in the evolution of the snow pack, or lessen the effect of an avalanche once it has occurred. For the event of human involvement, avalanche control organizations develop and train exhaustive response and recovery plans.
Deforestation is a major threat to biodiversity and ecosystems in Costa Rica. The country has a rich biodiversity with some 12,000 species of plants, 1,239 species of butterflies, 838 species of birds, 440 species of reptiles and amphibians, and 232 species of mammals, which have been under threat from the effects of deforestation. Economic advantages from cattle ranching, agricultural development, and logging have caused major deforestation as more land must be cleared to facilitate such practices. Despite government efforts to mitigate deforestation, it continues to cause harm to the environment of Costa Rica by impacting flooding, soil erosion, desertification, and loss of biodiversity.
Deforestation is one of the most serious environmental issues in Sri Lanka. Sri Lanka current forest cover as at 2017 was 29.7%. In the 1920s, the island had a 49 percent forest cover but by 2005 this had fallen by approximately 26 percent. Between 1990 and 2000, Sri Lanka lost an average of 26,800 ha of forests per year. This amounts to an average annual deforestation rate of 1.14%. Between 2000 and 2005 the rate accelerated to 1.43% per annum. However, with a long history of policy and laws towards environmental protection, deforestation rates of primary cover have actually decreased 35% since the end of the 1990s thanks to a strong history of conservation measures. The problem of deforestation in Sri Lanka is not as significant in the southern mountainous regions as it is in northern and lowland southern Sri Lanka, largely due to the nature of environmental protection.
Forest restoration is defined as “actions to re-instate ecological processes, which accelerate recovery of forest structure, ecological functioning and biodiversity levels towards those typical of climax forest” i.e. the end-stage of natural forest succession. Climax forests are relatively stable ecosystems that have developed the maximum biomass, structural complexity and species diversity that are possible within the limits imposed by climate and soil and without continued disturbance from humans. Climax forest is therefore the target ecosystem, which defines the ultimate aim of forest restoration. Since climate is a major factor that determines climax forest composition, global climate change may result in changing restoration aims.
Forest conservation is the practice of planning and maintaining forested areas for the benefit and sustainability of future generations. Forest conservation involves the upkeep of the natural resources within a forest that are beneficial for both humans and the ecosystem. Forests provide wildlife with a suitable habitat for living along with filtering groundwater and preventing runoff.
Bannwald is a German word used in parts of Germany and Austria to designate an area of protected forest. Its precise meaning has varied by location and over time.
A Steilhang is a geoscientific term for a steep mountainside or hillside, the average slope of which is greater than 1:2 or 30°. Leser defines a steilhang as a mountainside with an incline of between 16° and 60°, slopes of between 30° and 60° being described as "very steep" (übersteil) and anything over 60° being a rock face (wand).
A rockfall protection embankment is an earthwork built in elevation with respect to the ground to intercept falling rock fragments before elements at risk such as roads and buildings are reached.
