Pears for your heirs
An adage to encourage us to think long-term and look after future generations.
Pear trees, especially the old English varieties that would have been the subject of this proverb, take many years to mature and give fruit. You don't plant them for yourself but for your heirs.
The full version of the phrase, which is a 17th century English proverb, is:
Walnuts and pears you plant for your heirs.
The sense of the altruistic nature of tree planting was also expressed by Thomas Fuller in his work Gnomologia, 1732:
"He that plants trees loves others beside himself."