Trilobites: Why Does Fall Foliage Turn So Red and Fiery? It Depends. Many of the hypotheses for why leaves turn red before they fall off trees in the autumn sound contradictory. Share: Facebook Twitter Google+ Stumble Digg Email ThisBlogThis!Share to XShare to Facebook Related Posts:NASA news: LISTEN to eerie sound of energy moving between Saturn and Enceladus‘416,’ ‘Witch,’ ‘Not Creative’: How Fires Get Their NamesHow Brett Kavanaugh Could Reshape Environmental Law From the Supreme CourtFreed From Thai Cave, Boys May Still Face Health ProblemsBlood rain in Russia: What causes blood-red rain to fall from the skies?Moon landing 2019: Israel will plant flag in the moon when lunar probe lands next year