Age structure and recruitment of Trillium luteum (Trilliaceae) populations in secondary forests of the southern Appalachian Mountains

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College of Forest Resources and Environmental Science


Members of the genus Trillium are widely distributed in temperate hardwood forests. Due to shared life history traits, including long maturation, self-incompatibility, and limited seed dispersal, the genus is sensitive to anthropogenic disturbance, which reduces plant abundance and fecundity. In the southern Appalachian Mountains, Trillium species are widespread across a range of forest types, but are less common in secondary forests that originated following the abandonment of degraded agricultural land. One exception is Trillium luteum, which commonly occurs in floodplains formerly used as homesteads and farmland. We examined five populations of T. luteum in Great Smoky Mountains National Park to quantify population characteristics of this common, but rarely studied, species and relate these characteristics to historic disturbance. Plants within our sampled populations ranged in minimum age from 2 to 24 yr, with an overall mean age of 9.5 ± 0.4 yr. However, many plants may have been much older than our estimates due to rotting of the rhizome tip. We observed generally continuous recruitment across sites, but some sites displayed distinctly fewer young plants. Neither mean T. luteum density (plants 100 m–2) by life stage nor mean plant age were correlated with overstory density or stand age (P > 0.102). We found that 20% of single-leaf plants originated from sprouts on fragments of old rhizomes. This ability to reproduce vegetatively has been observed in other sessile Trillium species and may provide a reproductive advantage in floodplains and former agricultural lands exposed to regular substrate disturbance.

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The Journal of the Torrey Botanical Society