Why are falling leaves so important to Cyrano?

Cyrano says,

"Ay, see how brave they fall,

In their last journey downward from the bough,

To rot within the clay; yet, lovely still,

Hiding the horror of the last decay,

With all the wayward grace of careless flight!"

I think that Cyrano finds them a metaphor to life in general and perhaps a little foreshadowing of his own impending death.