Our work clarifies the long-term feedback mechanisms between biomass burning processes and forest community structure across different vegetation zones in the Altai-Sayan ecoregion. The findings hold significant scientific value for understanding human-fire-ecosystem interactions in the arid Central Asia, while offering historical references for regional sustainable ecological management.

Here we present the first tree-ring-based reconstruction of precipitation in sub-Arctic Sweden, extending back to medieval times. The reconstruction is derived from living and dead Scots pine growing in the rocky, drought-prone High Coast region (63° N). Unlike most high-latitude conifers that are typically limited by temperature, these trees thrive during cool, cloudy, and wet summers. This rare response enabled filling a significant gap in our understanding of historical climate variability.

During the Archean eon (4–2.4 Gyr ago), Earth's atmosphere lacked oxygen (O₂) but contained nitrogen, carbon dioxide, and methane. As cyanobacteria evolved, they produced O₂, while hydrogen (H) escaped, making Earth more oxidized. Around 2.4 billion years ago, O₂ levels rose, limiting hydrogen loss. Using 3D computer simulations, we found that atmospheric O₂ concentrations affect the upward diffusion of water vapor (H₂O). We therefore quantify the rate of hydrogen escape as O₂ changes.