Trees have a critical role in the global carbon (C) cycle. Tree photosynthetic assimilation is one of the largest C fluxes and forest biomass represents the largest C pool of the terrestrial biosphere. Understanding how tree function and growth respond to long-term environmental change is vital for predicting the future development of the terrestrial C sink. Stable isotopes from tree-ring cellulose represent a valuable and versatile archive where environmental changes are continually recorded. However, both the oxygen and carbon isotope composition of cellulose are controlled by more than one environmental factor, which presents a major challenge for interpreting these records. This proposed project seeks to overcome these major obstacles by developing a novel method that, via chemical modification of cellulose, is able to resolve the mixed climate signal in isotope ratios of tree rings. The developed model will be applied to two boreal forests for climate change studies.

2021

2025