@Sweet: I hate to burst your bubble, but chewing gum is not (I repeat, not biodegradable.)
Here’s one of many sites: http://www.grist.org/advice/ask/2003/06/26/umbra-gum/
“Why doth the gum blot the sidewalk and stay on the school desk for all eternity? Because, alas, it is made in part from not only non-nutritive but also non-biodegradable substances.
Every commercial gum has a gum base.The base makes up a percentage of the gum; the remaining ingredients are flavor and sugar. Gum bases are the part that we chew and chew and chew long after the flavor is just a memory. They are grouped in categories: elastomers (including natural and synthetic rubbers), resins, plasticizers (such as waxes, vegetable oils, and glycerides), adjuvants (including calcium carbonate, talc, or other charging agents), and antioxidants. In other words, the gum is, at base, plastic or rubber or wax.
The bottom line: Don’t spit your gum out in the compost or on the sidewalk, and don’t stick it under the table; put it in the trash. Contrary to persistent urban legends, you can also swallow your gum. It’ll eventually pass right on through, undigested. Yum.”