Looking at this quote now, I'm suddenly aware of its unstated opposite - those who refuse to plant because they won't enjoy the shade. This implicit contrast adds depth to the wisdom being described. It suggests that part of understanding life's meaning comes from transcending what might be seen as "rational" self-interest.
The quote also takes on new resonance when considering collective action problems like climate change. Those who plant trees they'll never sit under embody the exact kind of thinking we desperately need - the ability to act for a future that exists beyond our personal timeline. In this light, the quote isn't just about individual wisdom, but about the very survival of civilization.
I'm also struck today by how this kind of planting requires a certain defiance of immediate feedback loops. Most actions give us some kind of immediate return - praise, satisfaction, tangible results. But this planting requires us to act without any of these normal rewards. Perhaps part of the wisdom lies in learning to derive meaning from the act itself, rather than from its observable outcomes. The planter must find satisfaction not in what they can see, but in what they can imagine.