Green Food
When a leaf outlives its normal cycle, the carbon that collects the sunlight eventually breaks down. As the leaf dies and the tree begins to shed to hunker down for the winter, some leaves remain, and they eventually begin to look like this.
Celebrating St. Patty's Day
When the weather has turned, the wind starts blowing, and the snow starts to fall, sometimes a few leaves survive. Very rarely, a leaf like this can get left behind by nature. This is a very, very rare occurrence, and you should consider yourself lucky if you see a leaf like this.