Is it safe to drink water from trees?

It depends. Some trees such as birch, maple, coconut palms trees do have drinkable liquid called "sap", however drinking contaminated liquid can lead to serious conditions. Most species are not safe however, and in fact can be quite unpleasant if not outright dangerous due to being toxic or contaminated from insects. If you think your water is contaminated or unsure about water it's always best to seek an alternative sources in order to remain safe and healthy.