American forests are growing 42 percent faster than they are being cut and 380 percent faster than they were growing back in 1920. At least, that was true in 2000 when this report evaluating the state of forests in the United States was published by the U.N. Food and Agriculture Organization. Though the report is a bit old, its conclusions should be just as valid today.

What the report does not say is that the internal combustion engine is one of the main reasons for the healthy state of American forests. As recently as 1910, farmers used horses and other animals for almost all heavy-duty farm work. To supply these animals with food, farmers typically dedicated a third or more of their farms to pastureland. This pasture provided farmers with no direct revenue, just feed for their draft animals.

With development of the internal combustion engine and production of tractors, trucks, and cars on Henry Ford’s moving assembly line, these vehicles quickly replaced animal power, releasing the pasturelands for more productive uses. It is difficult to be precise, but data from the Department of Agriculture suggest that farmers converted at least 80 million acres of pastures to forests and another 40 million acres to crop lands.

In contrast, it is likely that urban sprawl led to the conversion of no more than around 40 million acres of land to urban uses. Urban areas today cover about 110 million acres, but if they had continued to grow at 1920 densities after 1920, they would still cover more than 70 million acres. So the internal combustion engine, which is often blamed for urban sprawl, actually allowed three times as many acres of land to be put into productive uses than were “consumed” by sprawl.

Of course, sprawl doesn’t really consume land, it just converts it to other, more productive uses. Sprawl doesn’t even consume open space, because low-density development includes lot of open spaces (such as backyards) that are probably far more valuable (in terms of frequency of recreation uses) than most rural open spaces. In any case, the net benefit of the internal combustion engine for land productivity is far greater than tis cost.