The Mishna (68b) teaches about what is included in the standard sale of a field, and distinguishes between different trees – ḥaruv she-eino murkav vs. ḥaruv ha-murkav – a carob tree that has not yet been grafted and one that has, and betulat ha-shikma vs. sadan ha-shikma – a wild sycamore tree and one that has been trimmed. According to the Mishna, these trees in their natural state are considered part of the field and are sold with it, but once they have been cultivated in different ways, they are independent and will not be sold with the field unless it is specified in the sale agreement.
With regard to the carob tree, Ceratonia siliqua, many carobs are found in the wild, where they do not grow tall nor do they produce much fruit; they are, however, hearty and strong. Cultivated carob trees grow tall and produce an abundance of fruit, but are usually weaker. To take full advantage of the carob tree, it was common practice to graft cultivated branches onto wild carob trees. Such trees – the ḥaruv ha-murkav – are considered more valuable than the simple wild carobs.
The sycamore, or Ficus sycomorus, is a tall, wide tree that is related to the fig. Although its fruit can be eaten, it was mainly grown for its wood, since it can produce large boards that are relatively light. It was common practice to allow the tree to grow for a number of years until its reached a large enough size, at which point it was trimmed and cut down for use, leaving behind the trunk – sadan ha-shikma – from which the tree would renew itself. After a number of years, upon reaching full height, the tree would, once again, be trimmed for use.