The latter term was new to me. It bears no relation to naval jelly (phosphoric acid), which is used on iron ships. Gum naval dates back to the days of wooden ships, when Georgia played an important role in the naval stores industry, as the New Georgia Encyclopedia relates:
In the late nineteenth and early twentieth centuries, Georgia was the world's leading producer of naval stores, which are materials extracted from southern pine forests and then used in the construction and repair of sailing vessels. Typical naval stores include lumber, railroad ties, rosin, and turpentine.The USDA Forest Service Southern Research Station Headquarters in Asheville, North Carolina, describes some of the nitty gritty of production. Here are two photo captions from their website:
The naval stores industry in North America originated in the mid-eighteenth century in North Carolina. Before 1800 the major products of the trade were raw gum, pitch, and tar. After the American Revolution (1775-83), processes were developed for distilling spirits of turpentine from gum. By 1850, 96 percent of U.S. naval stores came from North Carolina.
In the early 1870s North Carolina naval stores producers began migrating to southeast Georgia's sandy coastal plain to take advantage of the untapped virgin pine forests in that region. They brought their equipment and black laborers and established residential villages on large turpentine farms. By the mid-1880s about seven in ten turpentine workers in southeast Georgia had been born in North Carolina.
The industry grew so rapidly that by 1890 Georgia was the national leader in naval stores production, a ranking that lasted until 1905. Florida was the leader from 1905 to 1923, after which Georgia regained its predominance and maintained it until the 1960s.
Photo caption: Improved gum naval stores extraction methods require new tools and techniques. Bark streaks 9 feet from the ground require a special long handled tool for pulling the streak and safely applying the acid. A combination bark-pulling and acid-treating tool was designed to meet this need. The laborer is shown applying 50-percent sulfuric acid to a streak 8 feet from the ground. This tool enables a laborer to stand a safe distance from the tree and reduce the hazard of acid drifting down on his head and clothes.The punctuation in the second caption sucks rather badly, but the wonderful collocations make up for it. Jump-butts in this context seems to refer to the discarded lower portion of turpentined trees. Stumpage value is the calculated value of standing timber. The butt log is the often slightly irregular log taken from the base of a tree.
Photo caption: No more jump-butts and wasted timber as a result of turpentining. A turpentined tree containing both front and back faces and worked for 8 years is shown entering a German gang-saw to produce quality lumber. Developing conservative gu[m] extraction methods for the gum producer represents only half the problem, research must also prove to wood using industries that modern turpentining does not impair the stumpage value of the worked out tree.