The answer is a.less oxygen released into the atmosphere and more co2buildup; erosion could occur without the tree roots to hold the earth in place; loss of habitat of many animals and diversity could decrease.
Through the process of photosynthesis, trees absorb carbon dioxide from the atmosphere and release oxygen into the atmosphere. If the number of trees on earth continues to decrease significantly, less oxygen released into the atmosphere and more co2 buildup.
Tree roots hold the earth in place, so if the number of trees on earth continues to decrease significantly, erosion could occur without the tree roots to hold the earth in place.
Trees represent habitat for many animals, therefore if the number of trees on earth continues to decrease significantly, loss of habitat of many animals will occur and diversity could decrease.
