A keystone species, European aspen (Populus tremula L.), in boreal forests: Ecological role, knowledge needs and mapping using remote sensing

•European aspen (Populus tremula L.) is a keystone species in boreal forests.•Knowledge on the spatiotemporal occurrence and abundance of aspen is scarce.•Modern remote sensing techniques provide new opportunities to map aspen trees.•Remote sensing data can support aspen-related biodiversity management.