A história é "Hybrid" de "Galactic Odyssey", de Keith Laumer.
O livro é, na verdade, disponível da Livraria Livre do Baen, se você quiser relê-lo, embora Eu recomendo que você compre para apoiar Baen.
Deeper still, a secondary system of roots clutched the massive face of the bedrock; sensitive tendrils monitored the minute trembling in the planetary crust, the rhythmic tidal pressures, the seasonal weight of ice, the footfalls of the wild creatures that hunted in the mile-wide shadow of the giant Yanda tree.
...
"Alien, I die soon," the Yanda gasped. "But I will teach you. There is, however, a condition. . . ."