Fast forward to September 22, yesterday. In one week, the leaves are marked by toxic poisoning.
And the original leaves, from the spring growth, are useless. If the plant were healthy, it wouldn't shed leaves until frost.
Lows at night have been in the 60's.
"Because of the differing sensitivities among plants to ozone, ozone pollution can also
exert a selective pressure that leads to changes in plant community composition. Given the range
of plant sensitivities and the fact that numerous other environmental factors modify plant uptake
and response to ozone, it is not possible to identify threshold values above which ozone is
consistently toxic for all plants. The next few paragraphs present additional information on
ozone damage to trees, ecosystems, agronomic crops and urban ornamentals.
Ozone also has been conclusively shown to cause discernible injury to forest trees.757,758
In terms of forest productivity and ecosystem diversity, ozone may be the pollutant with the
greatest potential for regional-scale forest impacts. Studies have demonstrated repeatedly that
ozone concentrations commonly observed in polluted areas can have substantial impacts on plant
Because plants are at the center of the food web in many ecosystems, changes to the plant
community can affect associated organisms and ecosystems (including the suitability of habitats
that support threatened or endangered species and below ground organisms living in the root
zone). Ozone impacts at the community and ecosystem level vary widely depending upon
numerous factors, including concentration and temporal variation of tropospheric ozone, species
composition, soil properties and climatic factors.761 In most instances, responses to chronic or
recurrent exposure in forested ecosystems are subtle and not observable for many years. These
injuries can cause stand-level forest decline in sensitive ecosystems.762,763,764 It is not yet
possible to predict ecosystem responses to ozone with much certainty; however, considerable
knowledge of potential ecosystem responses has been acquired through long-term observations
in highly damaged forests in the United States.
Laboratory and field experiments have also shown reductions in yields for agronomic
crops exposed to ozone, including vegetables (e.g., lettuce) and field crops (e.g., cotton and
wheat). The most extensive field experiments, conducted under the National Crop Loss
Assessment Network (NCLAN) examined 15 species and numerous cultivars. The NCLAN
results show that “several economically important crop species are sensitive to ozone levels
typical of those found in the Unites States.”765 In addition, economic studies have shown
reduced economic benefits as a result of predicted reductions in crop yields associated with
observed ozone levels.766,767,768
Urban ornamentals represent an additional vegetation category likely to experience some
degree of negative effects associated with exposure to ambient ozone levels. It is estimated that
more than $20 billion (1990 dollars) are spent annually on landscaping using ornamentals, both
by private property owners/tenants and by governmental units responsible for public areas.769
This is therefore a potentially costly environmental effect. However, in the absence of adequate
exposure-response functions and economic damage functions for the potential range of effects
relevant to these types of vegetation, no direct quantitative analysis has been conducted."
Clearly, the EPA is well aware of the dangers to vegetation of ozone!
In an exciting discovery, it appears there ARE some scientists, at the Vulcan Project, emanating from Purdue, who are tracking emissions.
Here is the day's sadness, a dead finch. I don't want to make too much of anecdotal, quite possibly meaningless and random events. But this is the 4th time in my entire life of gardening and hiking that I have come across a dead bird lying on the ground from no apparent cause (kitty cat). The others were twice this summer - a blue bird, and a robin. And once last summer - I was so excited to be able to take pictures of a hummingbird which for once wasn't zipping around too fast to be caught on camera. And then it lay down on a big lily flower and died before my eyes. Draw your own conclusions.