Early conservation efforts
The impact of environmental destruction and economic sustainability was recognized in ancient times, as it is today. Response was varied; policy to minimize harvest in Lebanese forests was initiated by King Artaxerxes I in about 450 B.C., and trees were planted in ancient Greece to restore over-harvested forests.
The Roman Empire had an insatiable appetite for wood for building and ship construction. Vast amounts of wood were also used to fuel their baths. Private Roman baths consumed an estimated 114 tons of wood each year.
Romans developed a forest classification system to ensure supply could meet the varied demands. Forests were classified by use such as: coppice forests (stump sprouts after harvest) for needs that used small dimension wood (Silva caedua); state forests with large older trees reserved for military, naval, and large building construction; forests reserved to supply wood for public baths; and acorn production forests (Silva glandaria) to feed swine. By 167 B.C., Rome had prohibited timber harvests in Macedonia because of depleted forests.
Plant domestication
Plant domestication started with selections for desirable traits, such as seed or fruit size, within a wild plant species. Those selections were then propagated and refined by further selection cycles.
In any evolving civilization, sustenance of the general population by hunting and gathering eventually exhausts naturally occurring plants and animals around the growing urban centers to such an extent that even importation is not practical. Demand is met through cultivating selected plants in a managed environment. There are many examples of this occurring throughout history. Wheat was domesticated more than 10,000 years ago in the region we know today as the Middle East. Domestication of rice occurred a little later, about 8,000 years ago.
In the New World, maize (corn) was developed in approximately the same time frame as rice. Eventually, early colonial settlers found that Native Americans were cultivating a variety of crops, clearing the forest to create agricultural fields. The major crop species in eastern North America were the “Three Sisters” -- corn, beans, and squash, with beans and squash both being domesticated about 10,000 years ago.
The “take-home” message is that the progressive development of civilization has a negative and progressive impact on natural environments, depleting plant species that provide food or products used by humans. Domestication has been shown to mitigate the impact on natural resources by providing specific products in sufficient quantity to allow for continued population growth and further the development of a civilization.
In a similar manner, forest trees also were depleted from the natural landscape. Domestication has been relatively slower than row crops or horticultural plants, however, due to physical size, long-term reproductive cycles, and the length of time required to reproductive maturity.
In the United States, the vast forests of the east and west provided enough wood products to meet the nation’s needs without domestication until the 20th century. Increased domestication efforts began around mid-century in response to a growing demand for wood products caused by rapid population growth and the progressive harvesting of naturally occurring forests. Selection, testing, and breeding programs of certain conifers and short-rotation hardwood species -- such as poplars --important to the wood-products industry began at various locations in the country. These research programs were often led by or in conjunction with agricultural experiment stations at land grant universities and the USDA Forest Service.
Tree improvement
In Southern states, the Tennessee Valley Authority initiated a tree-improvement effort in the 1950s, which was somewhat different than other programs. A major emphasis of the TVA program was the early steps in fine hardwood species domestication. Fine hardwoods are trees that produce relatively valuable lumber, such as white oak, black walnut, and black cherry. At the time (and continuing to the present), high-grading harvest practices were common, which removed the best trees from the forest, leaving slow growing trees with often substandard form.
Domestication of selected forest tree species has been shown to be successful in producing faster growing trees with superior wood characteristics. For example, loblolly pine is now in its fourth generation of breeding and testing, and loblolly pine seedlings now planted in Southern states are all genetically improved.
Unfortunately, the last 30 years have seen a dramatic decline of tree improvement research and development nationwide. In Tennessee, the TVA tree improvement effort was suspended in 1982 because of a combination of budget constraints and the lack of success in planting hardwood seedlings. The Tennessee Division of Forestry’s 53 year-old tree improvement program was terminated in 2017 because of budget cuts in state government.
In contrast to national and state trends, however, the University of Tennessee’s Tree Improvement Program is still functioning. This R&D program was founded in 1959, when the Tennessee Agricultural Experiment Station (now referred to as AgResearch), within the University of Tennessee, hired a Norwegian-born forest geneticist, Eyvind Thor.
The program’s mission is to genetically improve forest tree species for increased productivity in the value areas important to Tennessee landowners. Professor Thor directed the UT Tree Improvement Program from 1959 until 1982 and pioneered work with a number of hardwood species, including yellow poplar, American chestnut, northern red and white oaks, and coniferous species such as eastern white pine, loblolly pine, and Virginia pine.
Thor was also one of the founders of the Tennessee Christmas tree industry and supported it through various research studies. Following his retirement, the university hired the author in 1984, who continues to build upon the very firm foundation laid by Professor Thor.
The second installment of this series will introduce the University of Tennessee’s Tree Improvement Program (UT-TIP) to Hellbender Press readers and describe the Program’s R&D efforts and cooperation with state and federal agencies and the Jack Daniel Distillery. Part III will discuss applications of the UT-TIP research in the changing forests of the future.
Scott E. Schlarbaum is a professor at the University of Tennessee and the director of the UT Tree Improvement Program.
