It seems that the advance of civilization inevitably entails paving paradise to put up parking lots. And you can't lay tarmac around trees. Out here in the country, rare is the summer day that isn't disturbed by the distant -- or not so distant -- buzz of chain saws echoing around the mountains. Whether it's an actual parking lot, or a new housing development, shopping center or home going up, the trees come down first. Not even sumac can grow fast enough to keep up with the onslaught.

So it is a little surprising to realize that there are more woods in Pennsylvania today than a century ago. According to Jim Finley, a forester associated with Penn State University, about 60 percent of the state is forested now, compared to 40 percent a hundred years ago. The major period of exploitation - when most of the state's original woodlands were logged off, for lumber and fuel and to create farms - happened from 1885 to 1930. See the article here.

That the woods have been reclaiming lost ground is apparent to anyone who walks them here in the northeast. Almost forty years ago I used to hike to the top of the mountain behind my parent's house and climb over the stone walls fencing in the groves of white birch growing where corn, potatoes or alfalfa once thrived. Perhaps today the birch have been supplanted by the hemlocks which even then were encroaching from all sides.

While orienteering I've often followed the reassuring handrail of an old stone wall through otherwise thick and trackless vegetation.

The walls are the remains of family farms -- a way of life pushed into oblivion by corporate agriculture. Most of the stones were probably dragged out of the fields by horse or ox power. The stones in the wall in front of my grandparents' house arrived on a horse drawn cart my grandfather borrowed. One summer he had been hired to paint an enormous barn a few miles away. In the evenings, he'd interrupt his walk back home to carry a few rocks to the edge of the fields he crossed. No doubt the farmer was pleased to be rid of them. When the job was done my grandfather used the rocks he'd collected to build the wall that still fronts the sidewalk today.

Field stone is much in demand now. All over the countryside the remaining walls are being sold off, torn down, their stones shipped away to be transplanted into walls, walks, patios and fancy stonework in affluent suburbs whose inhabitants lead lives far removed from the soil.

Before long the only stone walls remaining will be the inaccessible ones, embraced and protected by the returning forests.