Very interesting question. Organic material undergoes a series of processes in soil leading to different pools such as a labile or active pool, intermediate or slow and stable or inert or recalcitrant pools (Smith et al. 1997). These are conceptual pools with characteristic turnover rates ranging from less than one year to thousands of years. The pools exist in a continuum between labile and stable pools, as shown in, rather than fixed pools (Davidson and Janssens 2006). These conceptual SOM pools are defined by their different turnover times and their pool sizes (Smith et al. 1997, von Lützow et al. 2007). The labile C fractions are increasingly used in agro ecosystems research because they respond more sensitively to changes in land management (Cambardella and Elliott 1992, Chan 1997).
Since carbon sequestration is a functional of somewhat medium term to long term due to highly labile nature. However, carbon sequestration in the biotic form as trees is possible, how much does it do in one year or less time is physically measurable using destructive method. Best wishes.