Urbanization causes a variety of negative ecological impacts, impairing forests, streams, and other ecosystems. While urban forests are the subject of increasing research attention, planted urban forests are less well-understood than remnant forests; however, these systems may be distinct in terms of ecosystem structure and function. The current study investigates a chronosequence of reforested urban sites in Lexington, KY, USA, with a focus on overstory and understory woody plant community characteristics. Monitoring plots were established in each of the 20 sites; tree height, dbh, and species were surveyed for the overstory, and species and height were surveyed for the understory. Canopy height increased non-linearly with time since planting, rapidly increasing in years 6–10, but remaining relatively steady after year 15. While the overstory was dominated by planted native species, the understory was predominately non-native species, some of which are considered invasive. Overall, the nonlinear logistic relationship of canopy height to time since planting may be driven by species-specific effects—with trees such as ash (Fraxinus spp. L.) and black locust (Robinia pseudoacacia L.) important during the early years after planting, but declining over time due to pests and other pressures. Alternatively, this complex relationship of canopy height with time may be driven by uncontrolled factors such as site quality, landscape position, planted species, etc. The significance of invasive species in the understory suggests that the long-term health of these sites will be compromised without intentional ongoing maintenance to ensure continued forest development toward desired native community characteristics.
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Research was funded by a University of Kentucky Sustainability Challenge Grant, which is a collaborative effort of the President’s Sustainability Advisory Committee, the Tracy Farmer Institute for Sustainability and the Environment, and the Office of Sustainability. APC funded by Sena’s Storkan-Hanes-McCaslin Award.
The data presented in this study are openly available in the Environmental Data Initiative repository at https://doi.org/10.6073/pasta/f22406ee858daeb0b8bf3e6f4ed2ba00 (accessed on: 19 March 2021), reference number, https://doi.org/10.6073/pasta/fdcb15813501becc1ce898972a19378a (accessed on: 16 April 2021), reference number, and https://doi.org/10.6073/pasta/247c204871488a6ba981386fc3731559 (accessed on: 16 April 2021), reference number.
Sena, Kenton L.; Hackworth, Zachary J.; and Lhotka, John M., "Forest Development over a Twenty-Year Chronosequence of Reforested Urban Sites" (2021). Lewis Honors College Faculty Publications. 4.