Science Magazine – August 4, 2023 issue: DNA was sequenced from 27 African Americans buried at Catoctin Furnace, Maryland, where enslaved people labored between 1774 and 1850. The tree trunk forms a double helix comprising 27 segments representing each sequenced individual.

‘We’re changing the clouds.’ An unforeseen test of geoengineering is fueling record ocean warmth

Pollution cuts have diminished “ship track” clouds, adding to global warming

Tropical trees deter similar neighbors

Tropical forests host an unusually high diversity of tree species. Strong interactions between individuals are hypothesized to create these patterns. A tree is more likely to survive when surrounded by different tree species with different resource needs, diseases, and herbivores. Kalyuzhny et al. found patterns consistent with this mechanism in a long-term forest plot in Panama. Adult trees in this site are more distant from members of their own species than from other species and more distant than would be expected by chance or by the limits of seed dispersal. This study shows that distances between conspecifics are maintained in adult trees, helping to explain the high diversity of tropical forests.