Field responses of Prunus serotina and Asclepias syriaca to ozone around southern Lake Michigan [An article from: Environmental Pollution]

This digital document is a journal article from Environmental Pollution, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Higher ozone concentrations east of southern Lake Michigan compared to west of the lake were used to test hypotheses about injury and growth effects on two plant species. We measured approximately 1000 black cherry trees and over 3000 milkweed stems from 1999 to 2001 for this purpose. Black cherry branch elongation and milkweed growth and pod formation were significantly higher west of Lake Michigan while ozone injury was greater east of Lake Michigan. Using classification and regression tree (CART) analyses we determined that departures from normal precipitation, soil nitrogen and ozone exposure/peak hourly concentrations were the most important variables affecting cherry branch elongation, and milkweed stem height and pod formation. The effects of ozone were not consistently comparable with the effects of soil nutrients, weather, insect or disease injury, and depended on species. Ozone SUM06 exposures greater than 13ppm-h decreased cherry branch elongation 18%; peak 1-h exposures greater than 93ppb reduced milkweed stem height 13%; and peak 1-h concentrations greater than 98ppb reduced pod formation 11% in milkweed.