Water relations of trees growing in Green Infrastructure (GI) storm water trenches
Thursday, June 9th
Storm water management is a major concern for cities with outdated combined sewer systems. Uncontrolled storm water pollutes urban watersheds, and impairs ecological functions in streams and rivers. Evapotranspiration by trees is expected to be a significant GI component that diverts water from sewer systems, and storm water interception by green infrastructure (GI) installations with urban trees will likely be a major contributor to improving overall runoff control. It is important to assess the performance of these trees to better understand their contributions to storm water management.
The first research project has focused on water relations of trees in a GI tree trench system in the Mt. Airy section of Philadelphia. Acer rubrum ‘Armstrong’ and Platanus × acerifolia ‘Bloodgood’ were evaluated from May through November for stomatal conductance, leaf water potential (Ψlf) and leaf area index (LAI). Water relation trends were evident, and a one-way ANOVA with post-hoc Tukey HSD test showed a significant difference between stomatal conductance rates of the two species, but not within species. Analysis of Ψlf data was performed using a Kruskal-Wallis test rank sum test followed by Dunn’s test of multiple comparisons. These analyses also showed significant differences between the ranked data of the two species. In general, through the entire growing season, P. × acerifolia had greater stomatal conductance and lower susceptibility to water stress than A. rubrum ‘Armstrong’.
A second research project has evaluated the stomatal conductance of 25 trees of 13 different species/cultivars located at the same site. The trees were monitored from June-October 2015. In the preliminary analyses, tree species exhibited significantly different levels of stomatal conductance throughout the season, implying that some species are better suited as urban stormwater trench trees than others. Furthermore, pairwise t-tests reveal that Koelreuteria paniculata and Prunus sargentii trees consume significantly more water within stormwater trenches compared to traditional, isolated tree pits, whereas Quercus macrocarpa trees showed the opposite tendency.
This research not only confirms that stormwater tree trenches can be effective at managing stormwater but it also holds implications for further application of stormwater tree trenches since the selection of tree species can determine the effectiveness of the system.
This webinar is eligible for 1 PCH CEU and is free
For more information, please click here: WATER RELATIONS OF TREES GROWING IN GREEN INFRASTRUCTURE
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