When purchasing trees, does the buyer have a claim to the land from which the trees are growing or not? This question is discussed in the Mishna (81a) and dealt with in detail in the Gemara on today’s daf.
According to the Mishna, if someone purchases two trees, he does not receive a claim to the land, but if he purchases three trees, then he does have a claim to the land. Based on this ruling, if only two trees are purchased then anything that grows from the tree belongs to the buyer, but if something sprouts from the roots of the tree – i.e. from underground – it will belong to the seller, who retains ownership of the land. Furthermore, if the trees dry up and die, he has no claim to the land whatsoever, and cannot replant in that place. If he had purchased three trees, however, the land remains his even if the trees were to dry up and die – his ownership of the land is total and is no longer connected with the existing trees. Our Gemara brings Rabbi Hiyya bar Abba quoting Rabbi Yohanan as teaching that someone who purchases three trees receives the area beneath them, between them and beyond them ki-melo oreh ve-salo – an area the size sufficient for someone collecting figs who is holding a basket with which to collect them.
The reason that the purchase of three trees gives the buyer ownership of the land is because three trees are considered to be an orchard. The Gemara explains that to be considered an orchard there must be a minimum of four amot between the trees – to allow for plowing between them – but no more than 16 amot between them so that they will not be considered too spread out.