At one stage I spent quite a bit of time working on the psychology of perception – how we make sense of the world around us and respond to it. One of the issues in perception is visual illusions and one of my favourite illusions is sea waves. We have all seen the waves rolling in towards the shore but, of course, the water itself stays more or less in the same place, only the wave moves – and that is not an easy concept. The water is, in fact, going round in circles which we are able to see only when the wave gets close to the beach and the depth of water becomes less than the diameter of the wave’s circle – forcing the wave to rise up and (significantly) curl down on top of us.
Another of the issues in perception is how, if our perception of something changes, our attitude to it is likely to alter at the same time. Driving through Italy and France, one of the striking impressions is how most of the mountains, even up to quite high summits, are completely covered in trees. The peaks and valleys of the hills are drawn by the tops of trees. The UK was once a complete rainforest like this (complete with lions, bears and wolves) before, for instance, we deforested the Lake District.
Trees are rightly in the news because, like all plants, they absorb CO₂ from the atmosphere which is important. But, for some reason which I really do not understand, little mention is made of their other, wonderful, ability – to release oxygen into the atmosphere. Like all planets that we know about, the earth does not naturally have any oxygen at all in its atmosphere, yet this is what we mammals need to breathe and live. Trees, bless them, take CO₂ from the atmosphere, use the carbon to build their trunks, branches and leaves and then release the oxygen they haven’t needed into the atmosphere to keep us all alive. We absolutely depend on trees for our very existence.
So, driving along Italian autostrades and most of the way north through France, I felt grateful for the huge amounts of oxygen which the deep forests around us were releasing. I perceived trees differently as a result.
I should perhaps also mention the other valuable sustaining attribute which trees are reputed to have – in Cornwall they say that, if you ever feel seasick, the remedy is to sit under a tree.