A deciduous tree drops its leaves before winter, and the decision is the tree's rather than the weather's. Short daylight trig a la of ce to fo where ea leaf jo the tw, and th layer grad cuts the leaf off from water and nutrients. Chlorophyll breaks down first, revealing pigments that were present all along, and the leaf finally falls under its own weight. Keeping leaves through a frost would cost the tree more water than it could replace from frozen ground.

Type only the missing letters. Each box is one letter, and the number of boxes matches the letters that are missing.