Well, this may explain Paul Bunyan.

Researchers from the University of California, Santa Barbara have concluded that chopping wood increases a man's testosterone levels by over 40%, even more so than competitive activities.

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The study, published in Evolution & Human Behavior, worked to determine how non-compeitive activities and exercises - like food production - compared. They tested the testosterone levels of the indigenous Tsimane people in Bolivia before and after they cut down trees. The results showed a 46.8% increase in levels following a wood cutting, which was 17% higher than the levels caused by playing soccer.

Although, this scene from "The Amytiville Horror" is not recommended for increased levels of testosterone