Gum naval stores cultivation refers to the labor-intensive method of extracting pine resin from the trees (the raw gum). The method of collection—tapping the trees—vaguely resembles that used on a rubber plantation or in a maple sugar grove. However, instead of preparing the tree to receive a pipe or tap, the tree is gashed with an inch-wide curved blade, called a "hack," to remove all of the bark down through the cambium layer. An angled piece of galvanized tin is then placed below the eight-inch-long, one-inch-wide gash (also known as "the streak") to direct the oozing sap into a quart-sized rectangular cup fixed to the tree. Each new "streak" is put onto the tree above the preceding one, and gradually a vertical "cat face" more than thirty inches in height is formed. Through the mid-twentieth century, a "puller," a type of hack that had a long handle, was used to extend the streak up the tree to a height of more than seven feet.