Who Plants More Trees - People or Squirrels?

Squirrels plant thousands of trees every year by forgetting where they buried their acorns.    Researchers found out that squirrels usually hide their acorns by burying them and go on searching for other ones. And after some time they return and gather their acorns back. But often they forget where they buried their acorns and after some times acorns grow into trees. And thus they play a great role in expanding of forests.
   Sometimes they even sneakily bury the other thing to fool other animals which try to steal their acorns.

source: wildlifejack