This is a pretty nice video from Rob at Sigma 3 Survival school that illustrates how to fairly easily get water from a tree. This could come in handy in a survival situation but according to the narrator is only effective 2 times a year (early spring and late winter) and works better with certain trees.
Rob also demonstrates how to use a root from the tree to support your canteen while the water flows into it.
Source: theprepperjournal.com