Searching for answers for your question, I found in Wikipedia that "a New York fish and wildlife technician named Richard Thomas had calculated the volume of dirt in a typical 25–30-foot (7.6–9.1 m) long woodchuck burrow and had determined that if the woodchuck had moved an equivalent volume of wood, it could move "about 700 pounds (320 kg) on a good day, with the wind at his back". Another study, which considered "chuck" to be the opposite of upchucking, determined that a woodchuck could ingest 361.9237001 cm³ (22.08593926 cu in) of wood per day."

I don't know why they're talking about 'chucking' dirt, when the question is clearly about 'wood'. And there seems to be a question about what 'chuck' means, from the answer about 'upchucking.'

My son-in-law says you'd count the number of woodchucks and the number of trees, and the answer would be the number of trees per woodchuck.

Thanks for your entertaining question.