Background and AimsSoil phosphorus (P) availability is pivotal for forest productivity. What subalpine trees seasonally enhance rhizosphere mediated P activation remains unclear.MethodsWe systematically sampled both bulk (BS) and rhizosphere (RS) soils from the dominant tree species of Abies fabri in the subalpine forests of eastern Tibetan Plateau during the early, middle and late growing seasons, respectively. The P fractions in the soils were analyzed together with low molecular weight organic acids (LMWOAs), phosphatase (ACP), and microbial biomass P (MBP) to reveal the pathways and drivers through which the trees promote soil bioavailable P (Bio-P) within a year.ResultsResults demonstrated that soil temperature and moisture enhanced the concentrations of Bio-P through the dissolution of inorganic P. In the RS, the increase in Bio-P was driven by the dissolution of inorganic P facilitated by LMWOAs. The rhizosphere also sustained a higher MBP, indicating a larger MBP pool that contributed to P supply. Critically, pathways for replenishing resin-Pi were unique, originating from recalcitrant residual P and organic P (NaOH-Po). In contrast, P dynamics in the BS were primarily governed by abiotic factors such as soil moisture, which influenced P leaching. Hence, available P fractions were derived from less stable pools (NaOH-Po and NaOH-Pi) in rhizosphere soilsConclusionAbies fabri actively engineers its rhizosphere, shifting P cycling from abiotic processes to targeted biochemical strategies. By exuding organic acids and fostering a larger microbial biomass, it unlocks recalcitrant P from sources that are inaccessible in the surrounding BS.