If worldwide deforestation is not regulated what could most likely result?

Answer 1

At one time, not so long ago, Europe was almost entirely deforested because of the need for wood. It was needed for building, heating, ships and other things. Where there were forests, there was empty land. People had no work and no way to help support themselves. One of the outcomes was the need to find more wood and to find work for the roaming, starving unemployed.
The New World was found and it was said to have forests from sea to sea. A squirrel could move from one side to the other and never touch the ground. We don't want to be like that again and we have to make sure that we use other building materials and recycle as much as we can.