I live in southeast Alaska, which has a rich history of clearcutting. If you walk through an old-growth forest or a forest that's been selectively logged, you see a variety of trees. You see spruce, hemlock, cedar, and alder. There's space between the trees for a variety of plants and animals to thrive.

When you walk through an area that's been clearcut, it's an absolute mess and there's no diversity. Plants and alder grow back very quickly, but they grow back very densely. In about 20 years, the fastest growing trees shade out everything else. Everything else dies, but they stay in place. It's really difficult to walk through an old clearcut because there are dead standing trunks everywhere. Humans don't like old clearcuts, but neither do other plants or animals. It takes centuries for truly mature trees to grow, and for the dead initial growth to decompose and open spaces to develop again.

In some places, the initial clearcut removes the only protection the soil had from being washed away. Where the soil is a relatively thin layer over, say, a limestone bedrock, the soil gets washed away before the process of regeneration can even begin. In those places, it will take millenia for a new forest to grow.

It's not as simple as "Trees grow back, and so do forests."

In any case, we have the ressources to address both pollution and the destruction of forests, there is no need to decide between the two.

One strategy is to remove the highest value trees from time to time, as they tend to be larger and removing them creates space for smaller trees to grow larger. Such harvests will also remove smaller trees that are unlikely to increase in value (often sold as paper pulp or wood chips, not necessarily discarded). This creates space for new trees to grow.

At the extreme you do have companies cutting down everything and using herbicide cocktails to prepare the ground for planting.