Willow aboveground and belowground traits can predict phytoremediation services

We explored traits-services correlations with plantations of short-rotation coppiced willows (Salix spp.). We conducted a four-year field trial (2016-2019) on a brownfield contaminated by trace elements (As, Ba, Cd, Cu, Mn, Pb, Se, and Zn), using split-plots nested into four blocks. We sampled 16 willow plantations (4.5m X 2.5m) of one or four cultivars from which half was coppiced after three years. For each plot, we measured ten functional traits from aboveground and belowground tissues (LA, SLA, LDMC, RDMC, LNC, RNC, LCC, RCC, SSD, and leaf pH) and six phytoremediation services (Phytoextraction, phytostabilisation, translocation factors, soil decontamination, and bioconcentration factors of total and belowground tissues). To do so, we measured trace elements in plant tissues and soil. We tested the impacts of treatments (willow diversity and coppicing) on the services and traits through linear mixed models and controlled for spatial heterogeneity with soil covariates (OM, texture and initial contamination). We explored the traits-services correlations through a redundancy analysis (RDA).