Honestly, I think the problem is that trees aren't balanced well.
Trees need to grow far slower and give far more wood. A tree grows in less than a year it seems like, and covers doorways and springs up in the middle of cleared areas instantly...
Cows, however, don't appear for 5 or 6 years and produce very little.
Balance is clearly a huge problem still, and trees are absolutely one of the worst problems. The foresters are very badly balanced because the trees are so out of whack.