I'd agree with this too!Its natures way of putting itself to bed
The rains and cool temps make the leafs drop to become food for next year
At least thats my hippie science on that one haha
Seasons change. Autumn comes. Fall happens. Winter sets in. Major death of plants, and animals occurs.
Leaving a very large amount of organic matter, to be broken down, and become available for new life in the spring.