COVER PHOTO: An Erman’s birch (Betula ermanii) forest in September 2016 at the treeline on Mount Norikura, central Japan. Windblown aphids originating in these forests drift uphill and fall on alpine snowpacks. They become critical foods for alpine birds, as described in Iijima and Murakami (doi.org/10.1002/ecy.70037). In autumn, the area turns yellow due to the autumn leaves of Erman’s birch. Photo credit: Daichi Iijima.