Tree Moisure Stress and Insect Damage in Urban Areas in Relation to Heat Island Effects    (View PDF)

Bert M. Cregg and Mary Ellen Dix

Abstract: We monitored crown air temperature, volumetric soil moisture, leaf water potential, rates of gas exchange, and insect pests of green ash (Fraxinus pennsylvanica 'Marshall's Seedless'), Austrian pine (Pinus rdgra Arnold), and northern red oak (Quercus rubra L.) trees during a relatively hot summer in Lincoln, Nebraska, U.S. Air temperatures and vapor pressure deficits (VPD) were much higher in trees growing downtown than in nearby trees growing on the University of Nebraska campus. Increased VPDs and reduced soil moisture decreased pre-dawn water potential and gas exchange of ash and oak trees on the downtown site compared to trees on campus. Green ash trees downtown had more damage from lilac borers (Podosesia syringae (Harris) (Sesiidae)) than did trees on campus. Aphids (Aphidiae) and lace bugs (Tingidae Corythucha arcuata (Say)) appeared to be more numerous on oak trees growing downtown than on those growing on campus. Cultural treatments that improve soil moisture availability, such as irrigating, increasing planter size, and mulching, are especially critical on heat island sites and may reduce tree stress, pest damage, and mortality.

Keywords: Tree moisture stress; urban heat island; plant water potential; net photosynthesis; insect damage.

https://doi.org/10.48044/jauf.2001.002