This song is probably about how useful something can be.
If we want to put good use to something, we must not throw it away, and waste it. Instead think of a good way to use all of it. 100 billion pounds of paper is thrown away each year. The phrase, if you eat too much, you'll get very fat means that there are many fat people, as well as poor people who could not afford food. The phrase, it could stand 20 years, if you pray it wood, means that if you treat something well it would last, and not be wasted. All the uses of the coconut tree can be replaced as a simple apple tree. It means that all tress are useful, and should not be wasted.