It’s intuitive to think that if a tree is photosynthesizing, it’s also growing. But that’s not necessarily so—and a new study of oak trees, published in the journal Science Advances, found that even as they photosynthesize late into the year, their growth stops by mid-summer. Much of the long-term carbon storage that forests provide depends on trees converting the carbon they absorb through photosynthesis into new wood. Many researchers have predicted that rising atmospheric carbon dioxide (CO2) levels will enhance photosynthesis and stimulate tree growth, putting some of that planet-warming carbon into long-term storage inside wood. However, the observed decoupling of photosynthesis from growth suggests that increased carbon uptake does not necessarily translate into greater wood production. Instead, some of the absorbed carbon may be used to produce foliage or used in short-lived metabolic processes rather than being locked away long term, reducing the amount of carbon stored in forests compared with previous expectations.

Despite being in contact with other Mediterranean cultures, the genetic identity of the Iberian people from the northeast of the Iberian Peninsula existing in the Iron Age remained largely stable throughout six centuries. Emerging from local Bronze Age populations, they evolved gradually without any major migratory movements bringing substantial changes to their DNA. It was not until the arrival of the Romans that they integrated new genetic influences that shaped a more diverse population, in parallel with the political and social transformations that took place.