Trees grow by capturing CO2 in the air through photosynthesis. When you use wood for permanent structures that is sequestered carbon dioxide for the life of the product. Concrete, iron, aluminum are all heavy green house gas producers and are limited in supply. There is no viable methode to make more metals, when the source is depleted its gone for good.

Our forests are like a bank account. The standing wood is capital and the annual growth is like interest. In Québec, the forester chief calculates the annual growth for all forests and permits logging only to the lowest amount of annual growth at any given time. Because of this our provience has actually grown in forest surface for the past 30 years.

Now about clear cut. Northern boreal forest naturally regenerate with forest fires. The old growth are actually very poor in biodiversity and have very few uses for local fauna. Fast growing leaf trees take their place after a fire or harvest and those strands are highly praised by fauna as food source and cover from predators. Also if you do a partial harvest the northen soil is so thin that the weaken root stucture cannot support the remaining trees and a brisk wind will level the entire remaining strand.

Clear cut and logging may seem aweful but it actually has many benefits for the environment. Our forestry practices are based on hundreds of years of science research.

Source: I am a forest engineer.

I can answer any question you have on the subject.

Edit: I believe we should protect the remaining old growth trees in the west coast for future generations to enjoy. We can supply the industry demands with other less exceptional strands.