# pypi, the Python Package Index, suggests tinytree, treedict, caxes, 
# treelib, pyavl... these are just the top few after filtering away the 
# many accidental hits (which point to specific tree such as XML ones, 
#                 AST ones, etc, etc;-). If you clarify what you want 
# to do with your trees it may be easier to suggest a specific package.

pip install treelib pyavl tinytree treedict caxes
# or 
pip3 install treelib pyavl tinytree treedict caxes