Two years ago i went out and bought several reusable shopping bags to put my groceries in so that i could stop using the evil plastic bags. Soon enough my supply of plastic bags started running out......you may be thinking, "yay, go you" but it started to hit me while i was walking my pooch that i had nothing to pick her poop up with! They sell bags in the store for just that thing but you guessed it they are plastic. I didnt really see the point in refusing to use supermarket plastic bags which i would later reuse to pick up after my dog and instead buying plastic bags to do the dirty work. I was wondering if anyone out there had a more eco-friendly approach to picking up after a dog that doesnt involve a plastic baggie.
I don't know if this is possible where you live, but where I live in one of the parks they have these 'metal bag holders" labeled for people to leave their plasic bags and then for others grab one when walking their dogs. This doesn't eliminate you using a plastic bag, but basically you're using a bag that somebody had anyway and would have probably just thrown away.
Oh, I just thought of the other thing I do. I have cats and kids so I also have the need for plastic bags for cat litter and poopy diapers. I save bags that you just can't avoid getting... eg, the bags from a loaf of bread or a bag from rice or from some other grocery items. You'd be amazed at how quickly these add up and while I wish I didn't have them, sometimes there is no way to avoid it and at least they get reused.
We have cats, and we also use the bags the newspaper comes in, but same problem, they're still plastic.
Of course these are made for dog poop, but we've been using Kyjen "Pooch Pick-up" bags (biodegradable cornstarch) to clean out the catboxes with: http://www.kyjen.com/shop/index.php/pet-travel-gear/pooch-pick-up-waste-management.html ....the nice thing is they have little handles on them which are easy to tie, and they're fairly easy to get the cat "deposits" into. We purchased ours a the local humane society pet store; looks like you can buy them online direct from the manufacturer, or probably could get them elsewhere online (I saw them on entirelypets.com). Good luck!