That's a huge difference from an oak tree. If we are talking about trees, the manchineel tree is a poisonous tree. No allergy is need here. Even standing beneath the tree during rain will cause blistering of the skin from mere contact with this liquid: even a small drop of rain with the milky substance in it will cause the skin to blister. Burning manchineel wood can cause blindness. It is so dangerous that authorities often place warning signs to caution people away from it. It's now an is an endangered species in Florida, but grows in the Bahamas and the Virgin Islands and the Caribbean, Mexico, Central, and South America.