If you take branches from trees they need to be baked as leaving them as in can carry mites that will live on the branch then go onto the bird let alone wild birds carry diseases And not all tree branches are safe heres a list of items safe and unsafe for budgies
http://americanbudgieforum.proboards.com/board/12/budgie-feeding
http://americanbudgieforum.proboards.com/board/12/budgie-feeding