פירוש על שביעית 1:5

הרי אלו מצטרפין – and they are considered as if they (i.e., the trees join together to form a single orchard) belong to one person, and they plow the entire Bet Seah for them.

Introduction This mishnah continues to deal with the question of when three trees in an orchard justify plowing the entire orchard up until Shavuot in the year preceding the sabbatical year.

וכמה יהא ביניהן – between one tree and another.

Three trees belonging to three persons, they join together and they may plow the entire bet seah on their account. The three trees count even if they are owned by three different people. In other words, what is critical is that there are three trees, even if they are not owned by the same person.

כמלא בקר וכליו - the yoke of an ox with the burden, and this is four cubits, but less than this, they are established as detached and they don’t plow from them.

What space should there be between them? Rabban Gamaliel says: sufficient for the driver of the herd to pass through with his implements. Trees must be properly spaced. If they grow too close to one another, then in order to care for them, the owner will have to thin them out. Therefore, if the trees in this orchard are too close together, they won’t count, because at least one of three trees is doomed to be cut down. Rabban Gamaliel says that the space left in between the trees must be sufficient for a person riding on animal to pass in-between while he is holding his tools. Any space less than this and one of the trees doesn’t count towards the necessary three trees needed to plow the entire field.