Next, and most importantly, with respect to trees that ‘line’ the roadway/highway, the purpose/intent was one of highway safety. During periods of low visibility on the roadway, most especially at night, wherein the headlights of the cars would reflect back from the painted tree trunks and make them more visible.

Today, this is not usually maintained as a practice, as it was in the past in the US. Here in California, on many of the old highways the were the predecessors to the modern Inter-States, the trunks of the trees were painted white for this reason. The older portions of Route 99, traversing California’s Central Valley, and many other highways from the era of the 1930’s-40’s and continuing into the 60’s, saw the roadway lined with trees that were painted white, from the base upwards about six feet. One can still see today, the traces of the white paint on some of the large older remaining trees, which line the more historic highways in this state.

Painting the bottom of trees white helps motorists.