Temporal insights into afforestation: A 25-year study of woodland expansion

Direct observation of transitions from farmlands to woodlands are rare, and habitat change dynamics are typically inferred indirectly from pseudo-chronosequence observations (space-for-time substitution). The aim of this study was to directly examine the transition of plant communities and soil properties as farmland developed into ex-arable planted woodland, in comparison to nearby ancient woodland. We collected plant identity and abundance records and topsoil cores for chemical analysis between 2001 and 2024. We additionally collected canopy openness data and soil cores for identification of soil fungal communities in 2024, to link plant communities and soil chemical properties with fungal communities and light availability. We modelled differences in species distribution across gradients of distance from ancient woodland. Our results showed that soil properties and plant communities in ex-arable and ancient woodlands remained significantly different 25 years after land-use change. Ex-arable woodland plots had higher pH, more available phosphorus, less total nitrogen, and less total carbon than ancient woodland plots. Changes in plant diversity were mostly associated with carbon to nitrogen ratio. The presence of ancient woodland indicator plant species was associated with higher light availability and proximity to ancient woodland edge. Ectomycorrhizal fungal communities were also significantly different in ex-arable and ancient woodlands, with higher fungal richness positively associated with soil pH and tree species richness. Our study suggests that woodland creation programmes should consider connectivity to ancient woodlands, time lags associated with plant and fungal succession, as well as the history of soil alteration practices, especially within woodland creation and compensatory schemes. • Ex-arable woodland was distinct from adjacent ancient woodland 25 years after planting. • Ex-arable soil pH and P remained higher and C/N ratio lower than in ancient woodland. • Ancient woodland specialist plant richness was associated with increasing C/N ratio. • Ectomycorrhizal fungal richness was positively associated with tree richness and pH.