Forests are natural dust filters, commit CO2 and produce oxygen. What does it mean in facts and figures? An extract of the Bayerische Staatsforsten, shows the forest's performance:
- One hectare of deciduous forest produces 15 tons of oxygen per year, coniferous forests even 30 tons per hectare and year.
- One hectare of forest filters up to fifty tons of soot and dust from the atmosphere every year. Compared to city air, the values are said to be more than 90% better.
- Forests are gigantic carbon dioxide stores. The exact amount of storage depends on the tree species and the local environment. Forests with an average age of 55 years bind 10.6 tons CO2 per hectare and year.
- Trees give so-called terpenes and essential oils, which not only give the forest its typical spicy smell and are beneficial for the bronchial tubes. This is due to the ability of essential oils to fight bacteria, germs and even viruses.
Clean air is essential for a healthy life. If we breathe in too many pollutants, this can have health consequences;
- irritation of the bronchi
- in deeper airways tissue damage and inflammation
- damage to the cardiovascular system
- damage to the pulmonary alveoli
Emissions from industry, agriculture, combustion processes and traffic are mainly responsible for air pollutants, especially particulate matter and nitrogen oxides. The German Society for Pneumology and Respiratory Medicine (DGP) therefore recommends that a "culture of air pollution avoidance" be specifically promoted - for further sustainable improvement of air quality.
Particularly in cities along busy roads the load is higher than in nature. Following the German Forest Protection Association large, contiguous forest areas near cities have a beneficial effect on the climate. The temperature differences between forest and city of 4° to 8°C cause a permanent exchange of air.
The green seems to be closely connected to humans, starting with the colour itself: "From the point of view of evolutionary biology it is obvious that there is a special relationship between humans and nature. The outstanding role of green nature is also underlined by the fact that the human eye can detect the color green in extremely high resolution. This alone is a clear indication of why people are always dependent on a green environment," said Prof. Dr. Joachim Heinrich, head of global environmental medicine at the Ludwig Maximilian University Munich.
The astonishing effect of the view into the greenery alone: The window view into the greenery alone helps people to get well faster after an operation. In addition, they need less painkillers than patients looking at grey walls. This was the result of a scientific paper by the Swedish physician Roger Ulrich, published in the magazine Science as early as 1984.
When you enter the forest, it quickly shields you from noise in a calming way. In addition, the treetops create a positive climate for the organism through their leaf canopy and through evaporation - the so-called forest interior climate is pleasantly cool with higher humidity, less wind and subdued light intensity. This alone can have a positive effect on headaches or respiratory diseases.
Annette Bernjus, Seminar leader for Forest Bathing and book author knows this demonstrably positive effect of the forest: "Forest is a natural stress killer. It demonstrably activates the Parasympathetic nervous system. It is part of the vegetative nervous system and is also called the "rest nerve". The stress hormones cortisol, adrenaline and noradrenaline are strongly reduced which is always good, also for the prevention of depression and burnout or: in acute cases. Breathing in the forest air substances does the rest and helps lower blood pressure. The better stress management also improves the quality of sleep."
When asked when the forest starts to unfold its positive effects, Bernjus replies: "Of course, just the sight of the forest has something soothing about it. Its effect begins with immersion in the forest - every minute in the forest does us good. Those who take two hours of time for the forest at the weekend create a good stress management depot for the working week. Because: the recreational effect in the forest lasts for a while."
Dr. Quing Li, a physician specializing in environmental medicine and professor at the Nippon Medical School in Tokyo, has been researching the relationship between forests and human health for many years. Among other things, he found out that stays in the forest also influence the number and activity of our natural killer cells in the blood. They can kill abnormal cells such as tumor cells and virus-infected cells. For example, stays in the forest could be a preventive measure against serious diseases. Forest and health research, the so-called "Forest Medicine" has been a separate discipline in Japan since 2012.
The current president of Japanese forest medicine, Quing Li, also coined the term "Shinrin-Yoku" = Forest Bathing. This natural therapy has been in existence in Japan since 1982 and involves the attentive perception of the forest with all five senses and the use of its healing effects.
The effects of forest medicine and nature are occupying researchers worldwide and are being taken more and more seriously. In Japan, Shinrin-Yoku has long been promoted by health systems as a health prevention measure - Japanese doctors even issue prescriptions for "forest baths".
Also the Shetlands announced in late 2018 that doctors may prescribe activities in nature such as sea walks, dog walks and the like on prescription. In parallel, the Shetland National Health Service has drafted a Monthly calendar with suitable small recommendations for outdoor activities.
The forest commissioner of the German government, Cajus Caesar, loudly demanded ZDF News the health insurance companies to use the healing forest more for health care.