Viewing the quote with fresh eyes today, I'm struck by its gentle subversion of traditional ideas about legacy. Many cultures emphasize having children as a way of extending oneself into the future, of achieving a kind of immortality. But here, the wisdom comes precisely from accepting that we won't personally extend into the future, while still choosing to enrich it.
The quote also seems to suggest something subtle about the relationship between understanding and certainty. The tree planter has certainty about what they won't experience (the shade), but must live with complete uncertainty about who will benefit, how they will benefit, or even if anyone will benefit at all. Yet this combination of certainty and uncertainty somehow opens the door to understanding life's meaning.
I'm also noticing today how the metaphor of the tree contains within it the idea of cyclic renewal - leaves fall and grow again, seasons change, the tree itself may eventually produce seeds that become new trees. Yet the planter's act is linear and singular. There's something powerful about how this one-time action by the planter taps into and contributes to these eternal cycles of renewal, even though they themselves won't be part of those cycles.