Good News for City Trees: Study Finds Resilience Against Air Pollution and Warming
Urban trees, a vital part of our cities' lungs, offer hope in the face of rising air pollution and warming temperatures. A new study by the Chinese Academy of Sciences reveals their capacity to adapt to these combined stresses, providing valuable insights for managing urban forests.
Published in Agricultural and Forest Meteorology, the research investigated how common urban tree species like Mongolian oak and Chinese pine cope with air warming and ozone pollution. The scientists exposed these trees to various temperature and ozone levels in controlled chambers, tracking their carbon flow using 13C isotope labeling technique.
They found Warmer air significantly increased the trees' biomass, photosynthesis rate, and overall carbon content. However, the effect varied between species and years. Elevated ozone levels, unfortunately, hampered tree growth, reducing biomass and photosynthesis in both species. Interestingly, Mongolian oak demonstrated a self-repair mechanism under ozone stress, allocating more carbon to heal leaf damage compared to Chinese pine. Combined stress isn't all bad, the study's most surprising finding is that moderate warming appears to mitigate the negative impact of ozone pollution. Under combined stress, both tree species maintained higher growth rates and carbon content than under ozone alone.Significance for the future: This research offers crucial information for selecting and managing urban tree species in a changing climate. By understanding how trees respond to environmental stressors, we can make informed decisions to ensure their health and maximize their benefits for our cities.
