Diversity Boosts Forest Carbon, Especially in Cold and Dry Places

Scientists studied 15 long‑term forest sites around the world, from tropical jungles to Arctic woodlands. They measured how many different tree species were present and how much organic carbon was stored in the soil, a key factor that helps slow climate change. The overall trend showed that forests with more tree species kept more soil carbon. When the climate was colder or drier, this link became even stronger. In such conditions, trees break down more slowly and the variety of species helps keep carbon locked in the ground. In warmer, wetter forests, faster decomposition can erase some of the extra carbon that diverse trees might add.The type of trees – whether they share similar traits or not – mattered mainly in the driest sites. In those areas, certain functional groups of trees were better at holding soil carbon than others. These results suggest that protecting a wide range of tree species is especially important in places that are cold or becoming drier. By maintaining diverse forests, we can enhance natural carbon storage and better protect against climate change.