Who would’ve thought that trees value their personal space? Well, they do … or, at least, some trees, particularly those of the same species, do.
Next time you go walking amongst trees, look up and you may notice gaps in the tree canopy, where trees appear to be avoiding touching each other. This phenomenon is known as crown shyness (sometimes also called canopy shyness, intercrown spacing and canopy disengagement). There have been various hypotheses to explain crown shyness: these include ‘reciprocal pruning’ caused by the trees rubbing together in windy conditions; ‘photoreceptor-mediated shade avoidance response’, a long-winded term for trees adapting to the shade caused by their neighbours; and the idea that trees are actively limiting the spread of insects by not touching each other (though, presumably, insects could simply crawl down one tree, across the ground and up the next!). Whatever the true reason, crown shyness can create some lovely patterns in the canopy and I’ll be looking up more often from now on.