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:Gravitational waves make ripple but this year's population BOOM could haunt worldMankind set to make historic first contact with aliens in new multi-million pound projectNational Biotechnology Committee Faces New Conflict of Interest QuestionsVera Rubin, 88, Dies; Opened Doors in Astronomy, and for WomenREAL TRANSFORMERS: Meet the monster robot which could work in RADIOACTIVE environmentsProbe into safety of Fukushima nuclear power plant after powerful earthquake hits region