Gum balls come from the sweetgum tree. They are called by many other names including liquid amber (The tree is in the Liquidambar genus). The gumballs are the seed pods. They start out green but turn brown and fall off the tree. Sweet gum trees have a nice shape and have beautiful fall foliage often with leaves that are several different colors. Shelby County Extension Director Jim Todd does note that beavers like sweet gum trees and can girdle and kill them.