1. Restoring the iconic Ulmus americana to urban landscapes: Early tree growth responds to aboveground conditions.
- Author
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Mikolajewski, Danielle, D'Amico III, Vince, Sonti, Nancy F., Pinchot, Cornelia C., Flower, Charles E., Roman, Lara A., and Trammell, Tara L.E.
- Subjects
TREE growth ,URBAN trees ,ATMOSPHERIC carbon dioxide ,CHLOROPHYLL spectra ,TREE planting ,URBAN growth - Abstract
Native trees provide a range of benefits, from supporting native wildlife to climate regulation, and many urban natural resource managers prioritize native tree planting and restoration. Ulmus americana (American elm) was once widely planted in American cities but has been decimated by Dutch elm disease (DED; Ophiostoma ulmi). Our study evaluated U. americana establishment and growth across urban landscapes. We planted ramets from three DED-tolerant U. americana genotypes (RV16, RV474, and Sunfield) along an urbanization gradient in Newark, DE and Philadelphia, PA, and assessed physiological and morphological responses. We analyzed how U. americana clone growth, chlorophyll fluorescence, and foliar chemistry relate to impervious surface area, ozone (O 3) concentrations, and soil characteristics. The one-year post planting mortality rate was low (4%) demonstrating these elms can withstand urban environmental conditions when provided ample water supply and protection from deer. As expected, the elms differed in growth rate, chlorophyll fluorescence, and foliar chemistry between the cities. Elms planted in Philadelphia had greater photosynthetic capacity in July (F v / F m = 0.76) and September (F v / F m = 0.75), while Newark elms had greater photosynthetic capacity in August (F v / F m = 0.78). Depleted foliar δ
13 C signatures in Philadelphia suggest elms are experiencing greater fossil-fuel derived atmospheric CO 2 than in Newark, possibly contributing to the greater growth rates observed in Philadelphia compared to Newark. Enriched foliar δ15 N and greater foliar %N in Philadelphia clones suggest they are experiencing greater N deposition from NO x -derived sources compared to Newark clones. Clones growing in Philadelphia had greater foliar nutrient concentrations despite growing in soils with greater heavy metal concentrations. These foliar-soil chemistry patterns suggest that clones growing in Philadelphia respond positively to urban environmental conditions in a large city, whereas clones growing in Newark may be experiencing N limitation in the first year of growth after planting. [ABSTRACT FROM AUTHOR]- Published
- 2022
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