Robert Falls, a PhD candidate at UBC in the 1980’s, might have been onto something..
“Falls theorized that flexing of the bark by the wind encouraged the cambium- the layer of growth cells beneath the bark – to produce extra wood. Falls subjected trees to what he thought might be comparable stress by scarring them with surgical tools. Sure enough, more wood grew at the site of the scars. Hearing the news, a professor in the university’s wood science department suggested Falls try using this discovery to grow trees with a square cross section.”