In the US, there are more trees now than 100 years ago. I believe the law is for companies that cut trees for products, to plant two for every one they cut down.
Now there are problems in the rest of the world with deforestation, and hopefully we can fix that.
The negative impact of pulping isn't limited to just deforestation and loss of uncommercialized land. I think wikipedia does a fine job to explain the impact:
If you've ever been to Maine, where the paper industry is important, you'll know there are further effects from "sustainable" planting. The trees are all young; there is no possibility of a high forest developing. The stench of chlorine is everywhere.