In the summers of my childhood, I would spend some weeks with my father in a college town nestled in the pines of East Texas. The house he shared with my grandmother had a sloping yard with spilling roils of ivy that led on one side into the untamed forest, where patchy grass and gopher burrows gave way sharply to the crunch of dried pine needles blanketing sandy soil underfoot. Walking through the forest was a thrill. Each journey was a test of how far in I would dare to go before the threat of its many dangers — the poison ivy and venomous insects I definitely saw, the mountain lions and snakes I imagined lurking out of sight — sent me…