Presidential Range-Dry River Wilderness

Acidic deposition of sulfates and nitrogen compounds from anthropogenic sources can negatively impact sensitive ecosystems. These compounds can acidify soil and surface waters, affect nutrient cycling and impact the ecosystem services provided by forests. Sulfates and nitrogen compounds are deposited in precipitation (known as wet deposition), as well as particulates and aerosols (know as dry deposition), or directly from clouds/fog vapor. Click here to learn more about how acidic deposition impacts ecosystems.


In the United States, there are many locations where measurements are taken of wet deposition, as opposed to dry or cloud deposition. However, not all National Forests or wildernesses are monitored directly. For this reason, staticstical models, using monitored wet acidic deposition, precipitation amounts, and topographic data are being used to provide a spatial estimate of wet acidic deposition for the eastern United States (Grimm and Lynch, 2004).


The purpose of this webpage is to provide summaries of the amount acidic deposition and how it changes overtime for an individual wilderness or National Forest in the eastern United States. By selecting the State and Forest or Wilderness, a time series of the annual distribution of wet sulfate (top), wet total nitrogen (middle) deposition, and precipitation (bottom) will be displayed. The influence of aspect and elevation in mountainous locations has a profound effect on both annual precipitation, and hence annual wet acidic deposition, which result in large annual distributions (estimated by the standard deviation) across forests. Mean annual trends in acidic deposition and precipitation are represented by the red line in each of the graphs as determined by linear regression. The historical mean (blue line) and 95% confidence interval are shown when no significant trend are present in the data.


Since 1983, the following has occured:


Wet Sulfate: The wet sulfate trend could not be determined because one or more multiple regression assumptions were not met, or the coefficient for the year and/or precipitation predictor was not significant. Therefore, the graphic below shows the historical mean of the annual wet sulfate deposition of 17.0 kilograms per hectare (kg/ha) with the true mean between 14.15 and 19.91 kg/ha for 95% the time.


Select a new location:






Convert Instructions

Enter a value into one of the boxes and then use your enter key or select (click) on a different box to see the equivalent amount expressed in a different unit of measure.


Graph Instructions

The X- and Y- axes can be adjusted. Click and Drag your mouse along the axes to scroll through the values. To adjust the scale of the axes, Click and Drag your mouse along the axes while holding the shift key and left mouse button.


The X-axis adjusts on each graph in unison with other graphs. Both the Y-axes (English and Metric) adjust together in each graph to remain accurate, but each graph's Y-axes adjust independent of other graphs.

 

Please note: the results will not display properly in Internet Explorer version 8.0 or earlier.

Sulfate (kg/ha): Sulfur (kg/ha): Sulfur (meq/m2):


Please note: The calculated value for Sulfate (meq/m2) is the same as Sulfur (meq/m2) shown above.

Wet Total Nitrogen: The wet total nitrogen trend could not be determined because one or more multiple regression assumptions were not met, or the coefficient for the year and/or precipitation predictor was not significant. Therefore, the graphic below shows the historical mean of the annual wet total nitrogen deposition of 4.9 kg/ha with the true mean between 4.30 and 5.42 kg/ha for 95% the time.



Total Nitrogen (kg/ha):   Nitrate (kg/ha):   Nitrate (meq/m2):


Please note: The calculated value for Total Nitrogen (meq/m2) and Ammonia (meq/m2) is the same as Nitrate (meq/m2) shown above.

 

Precipitation: The precipitation trend could not be determined because one or more linear regression assumptions were not met, or the coefficients for the year and/or precipitation predictors were not significant. Therefore, the graphic below shows the historical mean annual precipitation of 57.9 inches with the true mean between 53.90 and 61.9 inches for 95% the time.


Right click on one of the following links to download the data used to produce the graphics:

  1. Wet Sulfate

  2. Wet Total Nitrogen

  3. Percipitation

  4. Readme

 

Literature Cited

Grimm, J. W. and Lynch, J. A. 2004. Enhanced wet deposition estimates using modeled precipitation inputs. Environmental Monitoring and Assessment 90: 243-268.