Assessing the recycling of chlorine and its long-lived 36 Cl isotope in terrestrial ecosystems through dynamic modeling.

•Cl/36Cl recycling in terrestrial ecosystems for variable inputs is unclear.•Plant-soil interactions involve the combination of inorganic and organic Cl cycles.•A dynamic model was developed to estimate Cl/36Cl persistence in forest ecosystems.•Natural production of organochlorine in soil plays a major role in Cl accumulation.•Residence time of bomb-test 36Cl in soil organic pool was estimated at 800 years.