Owner of tree responsible for its maintenance

Dear PAO,

My aunt has been staying in our province since the start of the community quarantine. Since she is a widow and has no children of her own, I have been taking care of her house here in Manila. She has a huge mango tree that has not been trimmed, so there are branches that have gone over her property and partly blocks the sidewalk. I just want to ignore it because I do not know anything about plants. Some of the passersby who usually use the sidewalk have commented that I should trim it, but I am not sure if it is my aunt’s obligation. Please advise.