The numbers in test were set to 100% chance of drop to help with testing :P
They are now set to similar drop rates as mining.
Note that Rare and Very Rare wood can still spawn naturally, in addition to being found from time to time when harvesting other wood types.
"I have no data yet. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories instead of theories to suit facts."
- Sir Arthur Conan Doyle, Sherlock Holmes