Some years ago, when white oak was abundant, the railroads that now are using other cross-ties would not have even considered such material for use in their roadbeds.

The fact that other ties are now being used emphasizes the fact that we are short on oak timber in the sections where this hardwood formerly was common.
The furniture industry uses hardwoods of superior grade and quality.

The factories of this industry have moved from region to region as the supply of hardwoods became depleted.

Originally, these factories were located in the Northeastern States.

Then, as the supplies of hardwood timber in those sections gave out, they moved westward.