1) PAYING FOR DAMAGE THAT ONE WAS PERMITTED TO DO
OPINIONS: One of the enactments made by Yehoshua as a condition for taking possession of the land of Eretz Yisrael was that the owner of a vineyard must allow a person who became lost in his vineyard to cut down branches in order to find his way out.
The Gemara does not mention whether the enactment of Yehoshua merely permits the person to cut the branches in the first place, but nevertheless requires him to pay for the damage afterward, or whether the enactment completely absolves the person of any liability to the owner of the vineyard. The Rishonim present various opinions on the matter.
(a) The RA'AVAD cited by the Shitah Mekubetzes later (117b, DH u'Matzil Atzmo) writes that one certainly must pay for the branches which he cuts. The Ra'avad proves this from the Halachah in a similar case. When a person who was fleeing from someone who wanted to kill him broke dishes as he fled, he is obligated to pay for the dishes, with the exception of the dishes of the pursuer (Rodef). He is obligated to pay for the dishes because "he does not have the right to save himself with the money of his fellow man." Although he was in danger, since the danger did not come from the owner of the dishes he is obligated to pay for them. Similarly, one who becomes lost in his friend's vineyard is obligated to pay for the damages that he does to the branches, even though he has permission to break the branches in order to find his way out. It was his fault, and not the fault of the owner of the vineyard, that he became lost. This is also the view of the ME'IRI.
(b) The RASHBA (81b) writes that if not for the ruling of the Ra'avad (that the person must pay for the damages to the branches), he would have ruled that all of the enactments made by Yehoshua exemptions from payment, for that was the condition with which Yehoshua distributed the land. The Rashba proves this from the very fact that Yehoshua made an enactment to permit the person to cut branches in order to find his way out of the vineyard. If the person must pay for the damage that he does, there is no need for any enactment of Yehoshua; it is obvious that when a person saves himself at the expense of the property of someone else he must reimburse the owner.
The Ra'avad himself asks this question on his opinion. He answers that if not for the enactment of Yehoshua, it would not have been permitted for the lost person to cut the branches without the consent of the owner. Yehoshua enacted that he may cut the branches without the consent of the owner, as long as he pays afterward.
The Rashba cites further proof for his view that the person should not be required to pay for the branches that he cut. The Gemara later (end of 81b) lists other enactments that Yehoshua made which permit a person to damage someone else's property in order to save his own property, on condition that he pay for the damage afterward. (For example, he is allowed to cut the branch of his friend's bush so that his own bees do not migrate and establish their hives there, as long as he pays his friend for the branch. Similarly, when a person spills out his wine in order to use the barrels to save his friend's honey, the owner of the honey is obligated to pay for the wine.) If one must pay for the branches that he cuts as he attempts to find his way out of a vineyard, this case should have been mentioned in that list as well.
The KOVETZ SHI'URIM (#91) asks that, on the contrary, the Gemara later actually disproves the Rashba's opinion. The Gemara asks why the enactments mentioned in the later Beraisos are not included in the earlier Beraisa which lists the ten enactments that Yehoshua made. The Gemara answers its question by saying that the earlier Beraisa lists only enactments to which all Tana'im agree, while the later Beraisos mention the opinions of individual Tana'im. According to the Rashba, who asserts that the ten enactments listed in the earlier Beraisa include an exemption from payment, the Gemara should have answered simply that the enactment in the later Beraisos are not listed in the first Beraisa because they involve an obligation of payment. He leaves this question unanswered.
2) PICKING GRASS FROM A FIELD OF "TILTAN"
QUESTION: One of the enactments made by Yehoshua as a condition for taking possession of the land of Eretz Yisrael was that the owner of a field must permit others to pick grass from his field, except from a field of Tiltan (fenugreek), since the growth of the grass is beneficial to the Tiltan. The Gemara questions this from the Mishnah in Kil'ayim (2:5) which says that if types of grass and Tiltan grew together, one is not obligated to uproot it (to avoid the Isur of Kil'ayim) because the grass is not beneficial to the growth of the Tiltan.
The Gemara gives two answers. In its second answer, it says that the Mishnah in Kil'ayim refers to when the Tiltan was planted for the consumption of humans, in which case the grasses are detrimental to it. The enactment of Yehoshua was made for Tiltan that was planted for the consumption of animals, and thus it is beneficial to have the grasses growing together with the Tiltan.
The Gemara asks, "How do we know [for whom the Tiltan was planted]?" It answers that when planted for humans, it is planted in organized rows.
RASHI (DH u'Mena Yad'inan) explains that the Gemara's question is how does one know that a given field of Tiltan was planted for humans, such that one may pick the grasses there because of the enactment of Yehoshua.
Why does Rashi explain that the Gemara's question is merely how does one know that a field was planted for humans? Why does he not explain that the Gemara's question is how does one know that a field was planted for animals?
ANSWERS:
(a) The MAHARSHA (Mahadura Basra, DH Rashi) explains that Rashi does not explain that the Gemara's question is how do we know that a field was planted for animals, because it may be assumed that any field of Tiltan was planted for animals unless there are indications otherwise. Out of doubt, one must assume that the field was planted for animals, and thus one is prohibited from picking the grasses there. Yehoshua's enactment was that one not pick grasses from someone else's field when there is a doubt that perhaps the field was planted for animals. Yehoshua's enactment permits picking the grasses only when one is certain that the field was planted for humans. The Gemara's question, therefore, is only with regard to Yehoshua's enactment to permit one to pick grasses from a field planted for humans. The Gemara is asking how does one know that a field was planted for humans such that he may pick the grasses from the field.
The problem remains, however, that the Beraisa does not say that if the field was planted for humans, one is permitted to pick the grasses from it because of Yehoshua's enactment. The Beraisa says, in general terms, that one may pick grasses from a field "except from a field of Tiltan," and it does not specify what type of field is prohibited. Perhaps the Beraisa means that Yehoshua's enactment prohibits one from picking grasses from a field of Tiltan whenever there is a doubt whether it was planted for animals or for humans, and only when it is known for certain that the field was planted for humans is one permitted to pick the grasses. What, then, is the Gemara's question, according to Rashi, when it says "how do we know -- in a case of doubt -- that the field was planted for humans, such that one is permitted to pick grasses from it?" Perhaps indeed picking grasses is prohibited until it is absolutely clear that it was planted for humans!
(b) Because of this problem, the Maharsha suggests a different explanation for the Gemara's question. The Gemara is not asking a question on the Beraisa which discusses the enactments of Yehoshua. Rather, it is asking a question on the Mishnah in Kil'ayim: Why does the Mishnah not require a person to uproot the Tiltan that grows together with other grasses when the Tiltan was planted for the use of humans -- "how do we know" that it was planted for humans? People who see the field will assume that it was planted for animals and will think that the owner is transgressing the Isur of Kil'ayim! Because of this suspicion which will be aroused among people, the Chachamim should prohibit one from keeping the Tiltan and the grasses together in the field even when it was planted for human use. This is the Gemara's question.
(c) The PNEI YEHOSHUA answers the question of the Maharsha on Rashi in a different way. He explains that the words "how do we know" are not the words of a question. Rather, they are the continuation of the words of Rav Papa. Rav Papa is teaching that there is a Heter to pick grasses even in a field of Tiltan, in a situation in which it is known for certain that the Tiltan was planted for the use of humans -- where the Tiltan is planted in organized rows. (I. Alsheich)

81b----------------------------------------81b

3) THE FISHING-RIGHTS AGREEMENT OF THE TRIBES
QUESTION: One of the ten enactments made by Yehoshua was that anyone may fish in the bodies of water in Eretz Yisrael, as long as he does not spread out a "Kela" (or "Keli'ah"). This refers to setting up reeds in an area in the water in order to make a fence with which to snare fish. Such a trap is prohibited because it would disrupt the movement of boats (RASHI; see Background to the Daf).
The Gemara quotes a Beraisa which states that "originally, the tribes stipulated with each other that no one shall spread a Keli'ah, but that they may fish with nets and traps."
If the tribes initially made this condition among themselves, why did Yehoshua need to enact it?
ANSWERS:
(a) The YAM SHEL SHLOMO (in "Eser Takanos Yehoshua," Takanah 6) answers that Yehoshua enacted that any person is permitted to cast a hook or net to fish, and that he is prohibited from fishing with a "Kela." The owner of the body of water, on the other hand, is permitted to fish even with a "Kela." (This is not like the view of Tosfos, who says that the owner is also not allowed to fish with a "Kela"). Later, the tribes agreed among themselves that even the owner may not fish with a "Kela," so that he not prevent the boats of others from passing. However, this created an imbalance in the rights of the owner, since all other people now had the same fishing rights in the owner's body of water as the owner. Therefore, the tribes also enacted that others may fish only with a hook and not with nets, while the owner may fish with nets.
(b) The TORAS CHAIM answers that when the Beraisa mentions the agreement the tribes made among themselves "originally," it means that they added to Yehoshua's original enactment when they were G-d-fearing and upright. They "stipulated with each other" means that the owners of the bodies of water agreed that no one would spread a "Kela," but that they may fish with nets. Later, however, when the tribes became corrupt and parsimonious, the practice reverted back to the enactment of Yehoshua, which gave permission to everyone to fish only with hooks. (According to this approach as well, when the earlier Beraisa mentions that Yehoshua enacted that they may fish with hooks (and with nets) as long as they do not spread a "Kela," it refers only to others not spreading a "Kela." The owners may spread a "Kela.")
(c) The PNEI YEHOSHUA writes that when the earlier Beraisa says that Yehoshua enacted that anyone may fish in the bodies of water in Eretz Yisrael "as long as he does not spread out a Kela," those words do not describe part of Yehoshua's enactment, but rather they describe the tribes' own agreement among themselves. Yehoshua enacted only that every person has the right to fish with hooks. The Beraisa adds, "as long as he does not spread out a Kela," which was the tribe's addition to Yehoshua's enactment. The Beraisa relates the practical Halachah when it lists the initial enactment. This explanation is consistent with the view of Tosfos who says that the injunction against spreading a "Kela" applies to the owners as well. (See also MAHARSHA in Mahadura Basra.)