Autumn cleanup tips: Turning decaying leaves into environmentally friendly options

As the colder temperatures roll in, it's time so say goodbye to the fall colors.
Most areas are already past their peak time and the leaves begin to find a new home -- on the ground, in people's yards, on the sidewalks and in the streets.
So what should one do with all those leaves?
Often times, people bag up the fallen leaves and consider them garbage. However, this might not be the most environmentally friendly option.
When one bags up those leaves, they end up in a landfill. As those leaves sit in landfills, they produce methane, which can in turn pollute nearby air and soil.
One alternative is to just leave them in the yard.
Another option is to compost decaying leaves by chopping them up in one's mower and combine them with green material.
The result is a nutrient-rich fertilizer for plants.