Because forests can be so diverse,
profound knowledge is necessary,
around the forest close to nature and diverse
and sustainable management.
The forest as a habitat
Forest is the most natural habitat, the most diverse land ecosystem of all and the gene reservoir par excellence.
Deadwood habitat [© Photo: Dr. G. Strobel]
Its most important function is as a multi-layered ecosystem, a habitat for animals, plants, fungi and billions of micro-organisms. The forest protects its inhabitants, who depend on it as a habitat, by providing food, shelter and protection.
But not all forests are the same. Each of the countless forest species and compositions offers ideal living conditions for other adapted life forms.
Forest edge habitat in autumn [© Photo: Dr. G. Strobel]
No other form of land use is as diverse and provides refuge, food and shelter for so many living creatures as the forest.
Forest edges as contact and transition zones between forest and open land are characterized by small-scale changes in temperature, humidity, light and soil properties. This creates particularly diverse habitats for flora and fauna .
Soil structure (from top) humus overlay, A horizon (humic topsoil), B horizon (clayey brown soil), C horizon (weathered parent rock)[© Photo: Dr. G. Strobel]
Forest is a natural protection against water and wind erosion and promotes nutrient cycling.
Forest soil protects the landscape from soil erosion (erosion) by rapidly draining surface water. It binds the water in the soil cavities like a sponge and releases it again with a time delay.
The forest can also prevent the danger of soil slides, since the widely ramified root network of the trees provides support for the soil. This function is even more important the steeper the site. In the high mountains, intact mixed conifer forests are the most effective protection against debris erosion (debris flows) and snow avalanches.
The ability to protect the soil depends on the composition and structure of the forest. Staggered, stable mixed forests have ideal properties, since they not only partially evaporate water in the canopy due to the high surface area, but are also able to root the soil more intensively than a single-layer forest due to their different root systems (for example from shallow rooted spruces). It is essential for the soil protection function that the restocking tree species are "site-appropriate" are; that means naturally adapted to this forest site are.
Naturally diverse mixed stands also protect soils from acidification, such as from air pollutants ("acid rain"). Through their intensive soil rooting, they ensure that nutrients stored in the subsoil / in the weathering rock can enter the soil and nutrient cycle. Healthy mixed stands have a diverse, intact soil life (microfauna, microflora, mycorrhiza), that helps keep the forest floor in balance. This is why forest soil is the most natural soil ecosystem of all.
More information on our website Soil as a natural resource
Pure water from the forest [© Photo: Dr. G. Strobel]
Precipitation in the forest does not simply run off as surface water and lead to soil erosion, but rather seeps almost completely into the soil. With the help of humus, interspersed with root canals and animal passages, the forest floor can also absorb large amounts of water, for example after continuous rain and melt water periods, and therefore effectively protect against flooding. Forests can store water for a long time, so that groundwater and springs are fed and streams and rivers do not dry up even during long dry periods.
At the same time, forest soil is an excellent mechanical-chemical-biological water filter. It purifies the seepage water on its way to the source. Water that seeps into the forest and is filtered through the soil is oxygen-rich, clean and excellent as drinking water.
The drinking or. groundwater recharge is higher under deciduous forests than under coniferous forests. Due to the higher evaporation in spruce monocultures in the crown and soil area, only 305mm or 33% of the rainwater percolates into the soil with an annual precipitation of 920mm. 34% or 312mm evaporates and 33% or. 303mm consume the tree and herb layer.
In a beech stand the groundwater recharge is much higher. With also 920mm annual precipitation 47% resp. 430mm into the groundwater, only 18% resp. 166mm evaporate and 35% resp. 324mm consume the tree and herb layer. Beech forests are therefore "drinking water forests". (Source: German Forestry Council)
climate, visual, noise and immission protection
Forests are the best and a natural Air conditioning.
- The forest shades the forest floor with the tree crowns, but also with its shrubs and the ground plants, mosses and fungi. This reduces the drying out of the soil.
- The forest evaporates large amounts of water. The resulting evaporation-cold cools the inside of the forest. This forest climate can be experienced especially impressively on hot summer days, when it is in the (deciduous-mixed)- Forest is pleasantly fresh. Thus, the forest interior climate balances daily and annual temperature fluctuations, increases humidity, and increases dew formation.
- The forest is a natural wind and storm brake. It absorbs the wind energy through the trees in a springy way and slows it down. The forest interior climate is thus more windless.
- In winter, the dormancy of the air and the lower heat radiation have an effect (about frost nights) has a mitigating effect on the climate in comparison to the open countryside.
- The forest has a stabilizing and balancing effect on the climate in all seasons.
In times of annually increasing climate heating, the protective function of the forest for the local climate and – in the sum of all forests of the world climate – is of outstanding importance, which increasingly exceeds all useful functions.
The fact that these protective functions can also be partially transferred to urban areas is shown on our Urban Climate page.
Local-regional climate protection
Temperature differences of 3° to 6°C can occur compared to the open countryside, and 4° to 8°C compared to cities.
These temperature differences between forest and city enable air exchange. On hot summer days, this creates cool air currents into cities in the evening (Famous is for example the so called "Hollentaler", which flows from the Black Forest through the Dreisamtal to Freiburg), as long as the so-called "cold air corridors" are not blocked have been kept free for this purpose by urban development. Since the leaf organs simultaneously filter dust, soot and gaseous pollutants from the air, cool, purified air can flow into the populated areas.
[Keyword "fresh air corridorCool / cold air is heavier than warm air and has similar properties as a liquid. She can flow from forested mountains to populated valleys, if she has room to do so. If the flow of air is prevented by buildings, the air accumulates in real "lakes of air and cannot contribute to the cooling of the inner cities.]
Forest is a natural privacy screen.
The feel-good factor for people is much higher when looking at a forest than, for example, when looking at an industrial area. The view of the forest gives people peace, security and safety.
Forest is a natural Noise protection.
Forest protects from noise by buffering it.
This can be experienced impressively near the highway, for example, when comparing residential buildings protected by the forest with those unprotected by it.
Forest is a natural Pollutant filter.
It filters greenhouse gases such as carbon dioxide or gases harmful to health, likewise (fine)Dust and aeorosols from the air. For example, a hundred year old tree can bind a ton of dust per year.
Forest is a natural Carbon sink
Forest is a major carbon store (CO2). Wood consists of about half carbon. The trees get this from the air through photosynthesis. When one kilogram of wood grows, about two kilograms of CO2 are extracted from the atmosphere. In the course of its life, a 100-year-old spruce, for example, can take up to 1.8 tons of carbon dioxide out of the air. In Germany’s forests, about 1.2 billion tons of carbon are bound in the above- and below-ground biomass.