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Trees impact the chemical properties of the soil in which they grow. When planting forests, the choice of tree species and species combinations is thus expected to partly determine the spatial variation in soil properties, even in the early stages of forest development. We made use of a biodiversity‐ecosystem functioning experiment in Belgium, FORBIO (FORest BIOdiversity and Ecosystem Functioning). The studied site is situated on former agricultural land on loamy sandy soil and replicates tree species richness (1–4 species) and composition. Soil samples (0–10 cm) were taken at five locations in 1, 2 and 4 species plots. We measured the total C and N concentration, the Olsen P, the pH‐H2O and the available Ca, Mg and K concentration. We hypothesised that the within‐plot spatial variability would increase with species richness and that the between‐plot variability would decrease with species richness. We found little evidence to support our hypothesis. We only found a smaller within‐plot variability in monocultures than mixtures for Ca, pH and C:N. Potential reasons for the little evidence for the effect of tree species richness may include the fact that the forest is only 9 years old, the agricultural land‐use history and the soil texture. Further research in sites with different soil properties or different land‐use history is needed to generalise these results. Highlights: Variation in soil chemistry was studied in young forest plots varying in tree species richness.Larger within‐ and a smaller between‐plot variation in mixtures than monocultures was expected.Larger within‐plot variation in mixtures was only found for for Ca, pH and C:N.Little effect of tree species richness may be due to young age, agricultural land‐use history or soil texture. [ABSTRACT FROM AUTHOR]

As of 2020, the world has an estimated 290 million ha of planted forests and this number is continuously increasing. Of these, 131 million ha are monospecific planted forests under intensive management. Although monospecific planted forests are important in providing timber, they harbor less biodiversity and are potentially more susceptible to disturbances than natural or diverse planted forests. Here, we point out the increasing scientific evidence for increased resilience and ecosystem service provision of functionally and species diverse planted forests (hereafter referred to as diverse planted forests) compared to monospecific ones. Furthermore, we propose five concrete steps to foster the adoption of diverse planted forests: (1) improve awareness of benefits and practical options of diverse planted forests among land‐owners, managers, and investors; (2) incentivize tree species diversity in public funding of afforestation and programs to diversify current maladapted planted forests of low diversity; (3) develop new wood‐based products that can be derived from many different tree species not yet in use; (4) invest in research to assess landscape benefits of diverse planted forests for functional connectivity and resilience to global‐change threats; and (5) improve the evidence base on diverse planted forests, in particular in currently under‐represented regions, where new options could be tested. [ABSTRACT FROM AUTHOR]