There is no reason why each and every forested area need be preserved as such. If it is in man's interest that a particular forested area be developed or cut, for housing, industry, etc., there is no reason why this should not take place. If enough humans vote and believe that it should not be deforested, or if enough people are willing to pay their own money in order to buy that land and preserve it as forest, then that should happen. While some redwood giant groves should be preserved, if I may be forgiven the presumption of speaking for mankind, there is absolutely no reason why each and every giant redwood tree or grove needs to be preserved. There is no reason why all forested areas need be preserved as such.
Denuded land becomes indistinguishable from old-growth forest after a few decades.
Redwoods and sequoias are exceptions, because they do not burn. In fact, the forested area in North America has been increasing steadily since 1920. Ditto for Western Europe. Out of commercial interest, the private sector protects trees and forests better than federal bureaucrats. Many green organizations have recognized this and have been lobbying for privatization.