We are using woodlands for recreation, we pick berries and mushrooms and we select picnic sites at spots in the forest we like. Certain woodlands we tend to avoid, because the tree species and tree densities make them look dark and hostile or we hate prickly brambles. Forest structures that do not allow you to clearly see through the stems for at least 50-70 m can have an intimidating effect on some people. Surely we all have experienced the heart-lifting effect of a great day outdoors in the woods.
So what is this all about? How does this interaction tree-human, woodland-human really work? Is it the spatial structure of a woodland that creates an effect in our mind similar to the effect of a piece of artwork or of a building? Or is it the microclimate, a combination of light, humidity, noises and smells?
For most of these questions it is probably fair to admit that we simply don’t know. “Humans as part of the forest ecosystem” is not a topic that has been widely studied so far. Socio-economic relationships – yes, but not so much human behaviour and human health in relation to trees and woodlands.
In this context, I find two topics particularly interesting, the relationship between (spatial) forest structure and human health and human behaviour in terms of how trees are selected for various purposes.
Humans select trees for various purposes – e.g. as habitat trees (i.e. for their ecological value), for their timber value, for picnics, for playing, as Christmas trees and for burials among other reasons. In all these cases humans make decisions that depend on a wide range of different factors. One quite important factor, of course, constitute the trees themselves that arouse attention for their size, the straightness of their stems and for a certain aesthetic feeling they stimulate. Human selection behaviour may vary a lot between different people and also within the same persons at different times and in different situations.
For a long time it was assumed that forestry students would select trees according to their university textbooks or to the instructions of their professors throughout their professional lifetime. Variation between and within individuals was therefore ignored. Only recently it started to dawn on some people that it is worth considering this variation a bit more carefully and systematically. What are the reasons for this variation, does it matter, is it possibly even an advantage?
This research into human selection behaviour is part of a larger field of research where for example the voting behaviour of humans or the selection of products in supermarkets are analysed. How do humans distinguish between trees they like and those they don’t? How do they perceive the trees, which trees catch their eyes? This is simultaneous research into humans and trees. The data used in this research are often collected by non-scientists in forestry training programmes and then passed on to researchers for detailed analysis. Therefore this field is also an example of citizen science.
I found inspiration for this research direction in the work of my mentor Klaus von Gadow and the colleagues who worked with me at his Chair in Göttingen. At that time many shook their heads and could not understand how such a topic could ever matter. Now, 20 years later, the research question has eventually matured and attracted a lot of interest in a number of European countries. Xin Zhao, a PhD student and Carlos Pallares Ramos, an MSc student, are currently studying the statistical side of this topic at my Chair and we are planning new experiments to better understand human tree selection behaviour. Perhaps this is something you would like to join in?