What does the taboo of portrait photography mean by "growing trees on your head"?

When shooting people's scenery, we should try to avoid trees, telephone poles, buildings, flowers and plants in the background above the head of the person. After all, people are not suitable for being a "culture medium".

The so-called portrait photography is a form of photography with characters as the main object of creation. Portrait photography is different from ordinary portrait photography: portrait photography takes the description and expression of the specific appearance and expression of the subject as its primary creative task. Although some portrait photography works also contain certain plots, they mainly show the appearance of the subject.

An excellent portrait photography is the sum of many successful factors: expression, posture, composition, lighting, exposure and production, which are all components of a whole.