The Tree Of Life — C.L. Moore

Smith, shot down by the Space Patrol after his escape from a Martian prison, is hiding in the ruins of an ancient Martian city when he attracts the attention of one of the things that make that place their home. And what exactly is their home? -- A thing they call The Tree of Life. In a place where there are no trees to be seen, and precious little that's alive. . . .

Imagine Indiana Jones in Outer Space. Long before Spielberg ever thought of Indiana Jones -- a decade before Steven Allan Spielberg was born, in fact . . .