The correct answer is - D) clear cutting.
The areas shown on the map are the areas that are dominated by the vast deciduous forests in Canada. If these forests are not managed carefully, than there will have big environmental problems in the country, especially because of the clear-cutting of this forests for the needs of the lumber industry.
If the lumber industry isn't held back with strict laws and actions, than the forests will relatively quickly be destroyed and disappear, thus living empty space behind them. This mainly happens because of the irresponsible, and short-sighted view of the lumber industry, because they only cut down the trees in the forests but do not plant young trees in order to replace the ones they took down.
