from the writings of Rebbe Nachman of Breslov; translated by Rabbi Aryeh Kaplan
Many types of fruit do not grow in some lands, only because people do not understand.
The world has a foundation stone. Channels emanate from this stone, reaching every land. The Midrash teaches us that the wise King Solomon knew the details of these channels and was therefore able to plant all types of trees.
If people knew the exact location of these subterranean channels, they would be able to grow fruit trees even in these lands. They could grow many that never grow there now.
Each channel has the power to stimulate a particular species. Even if a particular channel does not pass through one land, all channels are intertwined and flow into each other. If one knew the exact place, he could plant any type of tree.
If one knew the location of all channels, he could dig a well and know where to plant trees around it. He could then make any type of tree grow.
The foundation stone of the world constantly rises and descends. If one knows its position, then he knows what to plant at a particular time.
All these things are concealed from the world for some things may not be revealed.
People say that the world is gaining knowledge, but earlier generations made the primary discoveries, and this took the greatest wisdom.
Later generations make discoveries only because earlier ones prepared the way. One generation makes the basic discoveries, and later generations apply them, but the latter contribution is really the smaller.
The Talmud says "If you would not have removed the piece of clay, you would not have found the jewel under it."
There are things that may not be revealed, for if they were revealed, later generations would make an idol of them. There is knowledge that may not be revealed, for later generations would use the basic knowledge and continually add to it, often irresponsibly. They could then develop concepts leading to cataclysmic discoveries.
It is written [Lev. 19:23] "When you enter your land and plant any tree... three years shall its fruit be forbidden to you". The Zohar teaches us that the evil forces of klipah dwell in trees duirng these first three years.
Earlier generations misunderstood this and thought that they were obliged to worship a tree during the three years that it was under the influence of the klipah. According to their error it was a logical necessity to make such a tree an object of worship.