Trees and Microbes Team Up to Improve Nitrogen Nutrient Processes in Future CO2 Conditions

Forest trees growing in air containing higher levels of carbon dioxide (CO₂) radically change the way they ‘cycle’ nitrogen, a key plant nutrient, with implications for forests as a nature-based climate solution.

In a new study in Science Advances, researchers at the University of Birmingham’s world leading Free Air CO₂ Enrichment (BIFoR FACE) facility in Staffordshire, UK examine how a ~180-year-old oak woodland responded after six years of exposure to the CO₂ levels expected by the 2050s and beyond.

They found that key processes managing nitrogen in the forest increased significantly under the increased CO₂ conditions. Nitrogen is a critical nutrient for living things, including trees, and while elevated CO₂ levels lead to a ‘carbon fertilization’ effect, previous studies have not unpacked the way trees and their microbial partners manage nitrogen in such future scenarios.

In the study, the oak woodland’s soil nitrogen cycling processes, responsible for meeting tree nutritional needs, increased by about 30%. Rather than remaining ‘hungry’ for more nitrogen, the trees maintain healthy nutrition by working with microbes to ‘mine’ it from organic matter in the soil.