When I was in Israel we picked pomegranates directly off the trees and eat them. I was told this was okay because it had something to do with being under the tree.
My question is two-fold,
Firstly, what is the source for this?
Secondly, does this mean literally under the tree or is it just a figure of speech?
When one picks fruits owned by a Jew in Israel, he is allowed to snack on them (אכילת עראי) until they become designated for maaser (נקבע למעשר), or, if he is planning on selling them, until he finishes his work on the harvest (גמר מלאכה). After that, he cannot eat from them at all until properly tithing them.
The most common ways of designating for maaser are bringing it into your house, separating Terumah, cooking it, or trying to eat it on Shabbat. Note that designation for maaser can only happen after the harvest work is completed.
