Actually when you look around Canada's north you can see how much of our forests have been turned into checker boards.

ARound my lake when you go to an area that has been forested, even with people planting trees and the such, the land is very unlike how it WAS before the forestry people came in. Basically these areas, when you visit them, look like, at their worst, small warzones. The way the ecology of the area has been torn to shreds doesn't seem to offer a great climate in which the regrowth of said ecology returns.

Areas where the ground has been torn up from massive roots transform into little canyons, as rain washes the topsoil and mud away to another area, which then becomes compacted down from the runaway much. This then dries into small areas of clay desert, and then wind pushes a choking dust in every direction, further burrying the good ecology.

As the little story above translates over into thousands of similar incidences, it all adds up to you panning your gaze over the area and just seeing obliteration. The trees that tree planters plant have their work cut out for them in the new conditions.