human activities have caused biodiversity simplification at local and global scales and raised concerns about potential effects on ecosystem functions and biodiversity conservation. in the past decades, there have been increasing efforts to better understand the relationships between biodiversity (loss) and ecosystem functions, mainly primary productivity, carbon storage, and temporal stability of productivity. however, there remain important aspects that are still debated and understudied. under the ongoing global environmental change, herein, (i) i reviewed and examined the predictors, drivers and mechanisms of forest background and acute tree mortality under global environmental change and particularly the interactions between drivers within and between two mortality modes; (ii) i tested the relationships between multifacet diversity (functional, phylogenetic and taxonomic) and biomass and stem mortality rates as well as the underlying mechanisms including biotic damage, stand density index and size inequality in natural forests, in british columbia, canada; (iii) i mechanistically studied the relationship between multifacet diversity relationship with temporal stability of productivity in natural temperate and boreal forests across canada. [...]