Ключевые слова: advertising, alternative, background, billet, black, concept, death, death of trees, e, ebook, ebooks, eco, ecological, ecology, education, elearning, electronic, environment, environmental problems, ereader, fell tree, felled, felled trees, flora, forest, knowledge, life, log, modern, natural, nature, object, oxygen, plant, read, reader, reading, save, screen, study, tablet, technology, tree, trees, white, wood, wooden,