The interplay of ozone and carbon dioxide on invasive forest plants has been overlooked in many assessments of ecosystem integrity. To address this interaction, an evaluation of leaf-level gas-exchange systems of native and invasive plants will take place at sites (Big Meadows, Dickey Ridge, Sawmill Run) within the Shenandoah National Park that vary in ozone concentration. These studies will focus on carbon assimilation and stomatal function (density, conductance, guard-cell normalized conductance) and will have complimentary urban sites (Washington, DC ; Baltimore, MD; Philadelphia, PA). In addition, common gardens will be planted at the Blandy Experimental Farm with the most common native and invasive species from these forests. These trees will be exposed to elevated ozone and carbon dioxide levels in leaf chamber experiments to detail the effects on leaf chemistry, photosynthetic rates, and herbivory that are not easily deduced from the park studies. In order to combat invasives it is necessary to understand why an invasive plant is better able to sustain itself in an area than the native that has evolved within those bounds. Air pollution may act as a disturbance in an area allowing invasives to take root, but we must understand why invasives are able to subsist.