There was a time in human history (not so long ago) that these forests really did exist. The vast Amazon and Congo basins, even the British countryside, which inspired J.R.R. Tolkien to create magical forests where trees could talk and move. And why not? Couldn't these magical places exist? Not perhaps Tolkien's ents, but a place so strong and wild, like in Conrad's Heart of Darkness, that humans could not grasp its power and meaning.
Thanks to those authors most of us can still imagine a truly wild place. Modern geography; however, does not provide such a pleasant reality. Deforestation has claimed much of the world's wildest places. Notably it has split them apart. Recent studies by North Carolina State University show that 70% of remaining forest is within 1km (.6mi) of the forest's edge. That doesn't leave much room for the wild things.
The closer edges also allow for foreign species to penetrate and disrupt the fragile forest ecosystem. Human hunting being perhaps the largest impact on the system as humans take out much of the larger game. This reduction in top of the chain predators has immense effect on the entire ecosystem as we have seen from studies like that of the wolves in Yellowstone National Park, as well as others.
There is no easy answer. Rapid human population growth demands large amounts of food and energy that are often supplied through deforestation. Still all hope is not lost; being aware of where your food comes from as well as embracing renewable energy sources can help. As can supporting companies who work to protect the world's forests. Every little bit matters; because it's about more than the loss of large carbon rich trees, and the destruction of unique habitat, it's about our imagination and our ability to believe in a place where the wild things are.
For a more complete understanding check out the article from The Conversation for information, graphs, and links to further statistics and researtch about forest fragmentation.