Sir file a police complaint next time someone enter your premises for trespassing and if they start fight for abuse and assault.
further since from fact it looks she is women and she is taking advantage of same so you should go and register a complaint before hand and further you should take to make boundary to your building so that they donot enter.
Further a civil suit can be filed for injunction against the neighbour and the occupants.
for tree you need to take permission from the municipal and forest department citing the damages and you can remove same from the premises. you need to make application before the forest officer.