Tapping the Rubber Tree
This primitive method of tapping the rubber tree will insure a large flow of sap, but will also endanger the life of the tree itself. In the cultivated orchards, the rubber tree is tapped in a more conservative manner, avoiding injury of the tree. But of course the principle involved is everywhere the same.
This image is from: Luther Burbank: his methods and discoveries and their practical application. Volume 11 Chapter 8