(Mishnah): One who plants for a fence or for beams, it is exempt from Orlah;

R. Yosi says, even if he said 'the inner [branches] will be for food, and the outer for a fence', the inner are obligated and the outer are exempt.

(Gemara - Mishnah): One who plants for a fence...

Source: It says "Etz Ma'achal'' - what is for food is obligated. What is for a fence, beams or [fire]wood is exempt.

Suggestion: If [we learn from there, we should say that a tree] for food (a fruit tree), even if he intended for a fence, should be obligated!

Rejection #1: "U'Ntatem Kol Etz Ma'achal'' (it is obligated only if he planted for food. We explained this like SHENOS ELIYAHU.)

Rejection #2 (R. Yosi): We learn from the beginning. It says "Shalosh Shanim Yihyeh Lachem Arelim Lo Ye'achel'' - do we not know that it discusses a fruit tree?! Why does it say "u'Ntatem Kol Etz Ma'achal''?

[This teaches that] what [was planted] for food is obligated. What [was planted] for a fence, beams or wood is exempt.

Rejection #3 (R. Yonah): We learn from the end. Since it says "uva'Shanim ha'Chamishis Tochlu Es Piryo Lehosif Lachem Tevu'aso'' - do we not know that it discusses a fruit tree?! Why does it say "u'Ntatem Kol Etz Ma'achal''?

[This teaches that] what [was planted] for food is obligated. What [was planted] for a fence, beams or wood is exempt.

(Beraisa - R. Shimon ben Gamliel): When is this [that one who planted for a fence, beams or wood is exempt]? It is when he planted for a fence, beams or wood something proper for them. If he planted something not proper for them, it is obligated.

Question: R. Shimon ben Gamliel said properly! What is the reason for Rabanan [who do not distinguish]?

Answer (R. Ze'ira): Rabanan agree [that a kind of tree not proper for a fence, beams or wood is obligated. R. Shimon ben Gamliel discusses] one who deviated from the normal way of planting. For wood - they are dense (fruit trees are planted sparsely). For beams - he trims [the branches, so the trunk will get thicker]. For a fence - the place of the fence proves [that this was his intent].

(Beraisa - in the name of R. Meir): All trees can have an intent that exempts, except for olive and fig trees. (They are esteemed; they are always for food.)

R. Meir holds like he taught elsewhere, for he said 'all trees are [called] barren, except for olive and fig trees.' (If one draped a vine over a barren tree, one may not plant other species under the entire tree.)

(Beraisa - in the name of R. Shimon): Intent for something exempt applies only to three species - Rimin (like plums), sycamore and caper.