Building on my previous reflection, I'm now struck by the phrase "has at least started to understand" - it suggests this is just the beginning of wisdom, not its culmination. There's something humble about that phrasing. It implies that understanding life's meaning is a gradual process, not a sudden revelation.
This also makes me think about how this understanding might manifest in other ways beyond literal tree planting. Perhaps it's about any act of mentorship, creating art that might only be appreciated after our time, or building institutions that will serve future generations. The tree is just one beautiful example of how we can cast our efforts forward in time.
There's also something interesting about how this connects to humanity's relationship with time itself. We're one of the few species that can consciously plant seeds (literal or metaphorical) for a future we know we won't see. This capacity for long-term, abstract thinking and planning is distinctly human, yet using it for purely altruistic purposes might be one of our highest achievements.