In the high-density plots—where the planted firs were only a few meters apart—the understory was dark. The floor looked bare except for rusty needles, their acidity slowing down the cycling of nutrients. Gray branches snapped off as we worked our way among the trees. I imagined the mycorrhizal network had taken on the pattern of the plantings, wiring trees together as if they were rows of telephone poles. It would become a little more complex as the bigger trees spread their limbs and roots, taking over the growing space where others had died. Our
