8 VIRGINIA FORESTS A typical round-leaf birch progeny population. There are no seedlings or saplings of the species in the understory despite millions of seeds having been deposited on the forest floor over decades. (PHOTO BY TERRY SHARIK, SEPT. 25, 2024) in 1994 and are ongoing today. For greater detail about all of the actions taken for the recovery of round-leaf birch, read “Virginia round-leaf birch (Betula uber) revised recovery plan” published by the U.S. Fish and Wildlife Service (Sharik, 1990) at www.fs.usda.gov/wildflowers/Rare_Plants/ profiles/TEP/betula_uber/index.shtml, and explore other related publications cited at the end of this article. Recovery efforts for Virginia round-leaf birch faced several challenges. To place the establishment of additional populations in the wild in context, it is important to note that the original population underwent severe decline—from 41 individuals initially in 1976 to 26 the next year to 10 in 1994 and to just three trees remaining in 2021—with all of this decline occurring on private land. The first wave of decline involved mostly subadults and was largely due to a combination of human factors, including removal of individuals for study and propagation purposes, vandalism, and transplanting of individual trees by one of the private landowners. The second wave of decline included mostly reproductively mature adults and was largely due to natural factors associated with the trees being stressed. The reasons for the third wave are unknown as the population was not monitored closely during this period of time. Notably, the decline occurred despite considerable effort to prevent it, and certainly elevated the need to establish additional populations in the wild. The Recovery Plan, as designed by the Committee, called for the establishment of 10 additional populations (also referred to as progeny populations) in the wild. All were to be on public (USFS) land and confined to the watershed where the original population occurred—but at some distance from it. To be on the safe side, the Committee decided to establish 20 populations across a range of sites where sweet birch was known to occur. Thus, 20 such forested areas in the Cressy Creek watershed were cleared of all woody vegetation, and 96 birch seedlings were planted with spacing that would create a closed canopy of birches and thereby exclude other tree species. The seedlings originated from six open-pollinated, round-leaf mother trees and four sweet birch mother trees in the natural population from seeds germinated in the greenhouse at Virginia Tech’s Homestead Research Center in Critz, Va., in 1982 and held in cultivation for two to three years before out-planting in 1984 and 1985. Additional seeds were germinated in 1985 for out-planting of seedlings in 1986 and 1987. Five populations were established in each of the four years. Individuals of the closely related and widely distributed sweet birch were included to allow for comparisons of growth rates, fruitfulness, and longevity with round-leaf birches. Seventy-four percent of the 1960 transplants were from round-leaved mother trees, and 76 percent had round leaves. Mortality, and to a lesser extent growth rates (diameters and heights) and catkin production, were recorded annually in all populations through 1993 and somewhat less frequently through 2003, followed by a hiatus through 2021 due to a lack of funding. Various methods were used to maximize survival of the trees over the years, including fencing around individuals to preclude browsing,
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