Trees, such as those in the deciduous forest, are very important to the environment. if the number of trees on earth continues to decrease significantly, what might be the result?

Trees such as those in deciduous forest are very important to the environment because they are primary shelter for the animals living in the forest. Animals will start migrating towards the residential areas as their shelter will be lost.There are many species of plants that can be used as a  source of medicine for the prevention and cure of diseases.  Trees are a great source of oxygen for environment. Some trees of deciduous forest grow near rivers and prevents soil erosion by binding the soil to the roots of the plant. Trees such as cottonwood, mountain ash,fruit trees are commercially important. All of the above advantages of the trees will be lost if there will be a significant decrease in the number of trees.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.