Urban trees in the urban hydrology cycle

Author

• Jorge R. VeraFollow

Date of Award

2026

Degree Name

Biological Sciences

College

College of Science

Type of Degree

M.S.

Document Type

Thesis

First Advisor

Dr. Kyle A. Palmquist

Second Advisor

Dr. Shane Welch

Third Advisor

Ms. Elizabeth Moss

Abstract

In urban forestry, trees provide numerous economic, ecological, and aesthetic benefits to the surrounding community. One of their key roles is intercepting stormwater runoff, reducing flooding risk, and improving water quality. Chapter 1 of this thesis characterized the ecological and economic contributions of urban trees on the Marshall University campus and provides guidance on their management and conservation in the future. Chapter 2 examined how urban tree species modify the urban hydrology cycle by altering the volume and timing of precipitation delivery. In Chapter 1, we inventoried 114 acres of Marshall University's main campus in Huntington, WV, from June 28^th, 2023, to August 21^st, 2024. We identified each tree to species and collected tree metrics to assess ecological services and overall tree health. The inventory was conducted using the i-Tree Eco (a peer-reviewed software suite based on the Urban Forest Effects (UFORE) model. Our spatially explicit campus tree inventory documented 1,150 trees comprised of 87 distinct taxa across 51 genera and 25 families. Campus trees were skewed to a smaller structural cohort, with 54.4 % of individuals in the smaller class (< 6 inches diameter at breast height). The campus canopy provided a total annual ecosystem service value of $17,940, $3,983.45 in annual air pollution removal, 227,200 gallons of annual storm runoff interception, and $3,715 in annual building energy savings. These structural and economic data were then used to develop a campus tree management plan designed to guide future planting, maintenance, and tree conservation strategies for the campus. In chapter 2, we investigated how urban tree species mitigate precipitation intensity by monitoring 21 individual trees across five focal native species: Acer rubrum, Platanus occidentalis, Quercus palustris, Benthamidia florida, and Cercis canadensis in the greater Charleston and Huntington area of West Virginia from summer 2023 through summer 2025. Stemflow, throughfall, and total precipitation were measured across discrete precipitation events using double-helix funnels and automated HOBO data-logging rain gauges. Data were evaluated using generalized linear mixed effects models (GLMMs) specified with a gamma distribution. We used this modeling approach to examine the responses of stemflow depth, stemflow as a proportion of precipitation, and stemflow lag time across a range of weather and tree structure variables. We captured 137 leaf-on events and 27 leaf-off events. On average, the canopy intercepted 25.97% of total precipitation, while stemflow lag time was 0.94 hours across all events, ranging from a minimum of 0.01 to a maximum of 9.4 hours. Mixed-effects modeling revealed that tree species as a categorical predictor explained very little variation; instead, continuous structural metrics and storm intensity drove hydrologic dynamics. Both stemflow depth and stemflow proportion exhibited a significant quadratic relationship with precipitation event size, peaking during intermediate storms. Continuous tree size metrics (leaf area and canopy area) had a significant negative relationship with stemflow depth and proportion, demonstrating that smaller trees are structurally more efficient at converting gross precipitation into stemflow. Conversely, stemflow lag time was driven by a significant positive interaction between precipitation size and tree size (DBH and canopy area), indicating that larger trees act synergistically with larger precipitation events to maximize temporal delays. Ultimately, these findings show that while small trees optimize localized volumetric routing during frequent, small precipitation events, large-stature species like Quercus palustris, Platanus occidentalis, and Acer rubrum maximize absolute canopy retention and temporal lag time during highintensity events. Urban forest management policies should prioritize the protection and preservation of mature, large-canopy-architecture trees to sustain critical, large-scale floodmitigation ecological services provided by trees in flood-prone regions.

Subject(s)

Urban forestry.

Forests and forestry.

Water resources development.

Adaptive natural resource management.

Water -- Distribution.

Water-supply engineering.

Botany.

Rainfall anomalies.

Red maple.

American sycamore.

Pin oak.

Flowering dogwood.

Redbud.

Floods.

Water quality.

Runoff.

Rain and rainfall.

Marshall University.

Charleston (W. Va.)

Huntington (W. Va.)

West Virginia.

Recommended Citation

Vera, Jorge R., "Urban trees in the urban hydrology cycle" (2026). Theses, Dissertations and Capstones. 2120.
https://mds.marshall.edu/etd/2120