Ancient dedesertification and climate changing

We have jungle in mountains and desert of Iran in the places that are located in very  dry climate, why ???
As Archeogeologist since 2001 I started researching to find that what mechanism mead this jungles model . and after 21 years we found great discovery. The trees were not natural ,they were man-made and  Terraces farming was the model.  after this discovery we want to find expansion of this mechanism and was unbelievable,   not only in Iran mountains but also in
mountains of Southwest and Central part to east of Asia,North and Northeast part to west of Africa, and the Andes Mountains, in South America to north American, from espain to Lebanon,  shows that, since thousands or tens thousands years ago, peoples  by making billions of water dams (traces farming)and planting trees, they have had mead the biggest desertification, and by planting trees in millions of square kilometers, they created suitable vegetation and sufficient humidity that caused decrease the weather temperature .
In this very efficient system, at first, the mountains are cut, and by stacking stone walls, terraces are built to retain soil and water, and then, trees are planted.  (Terrace Farming)
Why this mechanism was very useful ?
  Because 1-The roots of the Trees have also caused the dams stability.  2-The roots of the trees, penetrating into the ground,  and have created enough space for water to sink into the ground.
3- every year, trees by left the leaves and fruit improved  the quality of the soil and cover the earth surface
4- the trees shadow on the ground, have prevented the soil and stones from heating up,
5- the leaves of the trees have caught the sun's rays, and stored them in the form of organic matter.
So controled the temperature (global warming)
  This model had made ( positive climate changing )