I was looking up info about the CIS nations and found that they held their initial meeting at Белавежская пушча. I could not get a direct translation for пушча, but it seems to be a form of пуща. I could not find the declension for пуща anywhere and so I'm not sure if пушча is a form of пуща or if it is just a related word... a diminutive for instance. Any help resolving this mystery would be most appreciated!