For the sake of resilience and multifunctionality, let's diversify planted forests!

TLDR

Planted forests cover about 290 million ha worldwide, of which 131 million ha are monospecific and thus have lower biodiversity and higher disturbance risk than diverse forests. The authors argue that functionally and species‑diverse planted forests provide greater resilience and ecosystem services than monospecific ones. They outline five actions to promote diversity: raising awareness, incentivizing diversity in public afforestation funding, creating new wood‑based products, investing in research on landscape benefits, and strengthening evidence in under‑represented regions.

Abstract

Abstract 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.