Several studies indicate that touching the wood or leaves of a tree can indirectly stimulate the parasympathetic nervous system and produce a vagotonic action, with a measurable anti-stress impact.
Although scientific research in this sphere is limited, the works found in literature concur in detecting several benefits in response to the tactile stimuli procured by wood, especially in comparison with artificial materials.1-2
A pioneering study on the effects of tactile stimulation on human physiology showed significant variations in blood pressure and heart rate after contact with steel and other materials (variations not detected with wood).3 A subsequent study confirmed wood’s neutral effect compared to artificial materials, even when the surfaces to be touched were warmed up: contact with aluminium or plastic increased blood pressure, although this increase was inhibited if the materials were warmed up; however, blood pressure did not change in response to contact with wooden objects, even without being warmed up.4
More recently, it was demonstrated that touching the wood of certain arboreal species (e.g. Japanese cypress) with the palm of the hand or the sole of the foot prompts effects on brain activity (detected via the concentration of oxyhaemoglobin in the pre-frontal cortex) and on autonomic nervous system activity (measured via heart rate variability or HRV), contrary to what occurs when touching marble.5
In studies exploring the effects of the presence of wooden objects in controlled environments, the stimuli produced by tactile and olfactory components combine and so it is hard to isolate the contribution made by a single stimulus. The presence of wood (accessible to touch, such as wooden panels, furnishings etc.) usually incurs a concurrent olfactory stimulation produced by the volatile organic compounds released by the wood into the air.6
Studies conducted in controlled environments can easily be transferred to forest environments: touching the wood of trees with the hands and potentially the chance to step on ground covered with leaves and roots with bare feet can be considered functional in relation to the health benefits produced by immersion in a forest.

— Francesco Meneguzzo, Federica Zabini

Institute of BioEconomy, CNR - Sesto Fiorentino (FI) CAI Central Scientific Committee

More than half the global population lives in urban areas where exposure to nature is usually very limited, and often distributed unequally according to socio-economic status.1, 2
As well as the physical separation between urban zones and the “natural” world, in high-income countries 80-90% of time is spent indoors, carrying out sedentary activities and passing 6-8 hours or more every day in front of phone or other digital screens.3
In a very short time we have passed from a mainly outdoors existence with constant exposure to nature to a “constructed” space and a life lived mainly indoors.
In recent years, a number of doctors and scientists have begun to talk about a “nature deficit” and are exploring in greater detail the negative effects resulting from this deficit and, conversely, effects on human health associated with exposure to nature. In general, an increasing amount of wide-ranging scientific evidence is demonstrating a relationship between little exposure to nature and an increase in depression, anxiety and other “contemporary” disorders, especially non-transmittable ones such as cardiovascular or metabolic syndromes and so on.4, 5
In addition, it is also showing that exposure to nature is, indeed, associated with significant, measurable benefits for a huge range of psycho-physiological aspects.6, 7
Another field of study is focusing in particular on the effects of nature deficit on children and adolescents. It is becoming increasingly evident that contact with green spaces during the phases of growth is important not only for health but also for cognitive functioning, social behaviour and the capacity to develop positive, empathic emotions, as well as being associated with a reduced risk of psychiatric disorders in adolescence and adulthood.8

— Francesco Meneguzzo, Federica Zabini

Institute of BioEconomy, CNR - Sesto Fiorentino (FI) CAI Central Scientific Committee

Services rendered by trees to our planet range from carbon sequestration to the production of oxygen, to the conservation of the ground and the regulation of the water cycle. Trees support both natural and human food systems and provide shelter for numberless species, humankind included, via construction materials. While all forest ecosystems are important, tropical forests are essential for the planet’s equilibrium and for the very survival of the human species. Apart from the loss of an important player in atmospheric carbon sequestration, deforestation and forest degradation in the great tropical forests cause serious environmental impact, also thanks to their effects on climate regulation.1
Since 1990, primary forest surface – now present only in tropical and boreal zones – has diminished by more than 80 million hectares and more than a third of the forest surface has been lost compared to the time before the development of human civilisation.2
Carbon sequestration is the first and most evident service offered by our global forests. But they also play an even more important role in climate stability, thanks to their releasing large quantities of water vapour into the atmosphere that, by diminishing air pressure in the lower atmosphere, facilitates the flow of moist air from the oceans. Known as the “biotic pump” and postulated first by two Russian physicists, this mechanism is capable of transporting water vapour over huge distances far from the oceans, thus guaranteeing rainfall in many inland areas.3 In South America, the River Plate basin depends on evaporation from the Amazon rainforest for 70% of its water resources, and western China, which has the largest expanses of cereal crops, depends for over 80% of its waters resources on humidity recycled from the Euro-Asiatic forests (from Scandinavia to east Russia).4
This capacity for climate regulation is guaranteed above all by the great natural or unmanaged forests that are not disturbed by human actions. To safeguard them should be an absolute top priority within the context of the progressive changes of the global climate.

— Francesco Meneguzzo, Federica Zabini

Institute of BioEconomy, CNR - Sesto Fiorentino (FI) CAI Central Scientific Committee