Structure Condition Services Stressors
Mercury is a persistent toxin that can be deposited by wet and dry deposition, and found in water, air and soil. It is assimilated into plants and soils and then gets passed through various food webs where it accumulates in organisms, leading to damage with long-term consequences1. High concentrations of mercury can lead to a reduction in growth and reproduction in plants, and increases in the rate of wildlife mortality. Here, we quantify the annual amount of mercury deposited at an air quality monitoring site in Underhill, Vermont. A high score means that there is a low level of mercury deposition.
The score is calculated using a target value and the historical range of the the entire long-term dataset. The higher the score, the closer this year's value is to the target.
Once the score is computed for each year, the trend in scores over time is calculated. If the trend is significantly positive or negative, the long-term trend is marked as increasing or decreasing respectively.
Distance between target and maximum (scaled 1-5)
|Directionality of scores||
Lower values in the data are better.
|Minimum value used in scoring||
|Maximum value used in scoring||
Data maximum + 10% of range
Data on mercury deposition (μg/m2) were accessed from the National Atmospheric Deposition Program (NADP) Mercury Deposition Network (MDN) for sites at Underhill, Vermont1. Annual values are computed from weekly samples collected at the site. We set the target for mercury deposition to zero2. The annual score was computed as the difference between the target concentration of 0 μg/m2 and upper scoring bounds (maximum value in the data plus 10% of the range), scaled between 1 and 5.
Acid rain harms forests and other ecosystems by damaging leaves and leaching nutrients.
The length of the growing season varies from year to year, but large or persistent changes can be problematic to forests.
Ozone can cause many negative impacts to forests by reducing regeneration, productivity, and species diversity.
Mercury is a toxin that persists in the environment for long periods by cycling back and forth between the air, water, soil and organisms - resulting in long-term, negative effects to forest ecosystems.
Warmer winter minimum temperatures can allow for non-native species to proliferate, while at the same time stressing native forest trees.
Higher maximum summer temperatures can stress forests, reducing productivity and health.
Changes to precipitation can alter the water balance in Vermont’s forests, causing either drought or deluge.
Snow insulates the soil and tree roots from cold temperatures and provides water when it melts.
Climate change will continue to result in more extreme weather events, which can stress forests beyond what they are accustomed.
Lack of sufficient precipitation can cause both immediate and long-term stress to trees.
As native trees are not adapted to defending themselves from non-native, invasive insects and diseases, widespread damage and mortality can result.