Past Research

Impact of Intensive Production Forestry on Water Quality

TexIS (Texas Intensive Silviculture Study) Bulk Density Evaluation

Soil Carbon Monitoring Project

GPS Accuracy Assessment

The Spatial Variation of Floods with Return Periods Greater Than 100-year in the Conterminous United States

User Trails Utilized by Commercial Pack Stock on the Inyo National Forest


  Stephen F. Austin State University

  - Texas Alto Watershed Project with Dr. Mingteh Chang and Matthew McBroom

   Impact of Intensive Production Forestry on Water Quality

    The main objectives of the project are to assess the impacts of forest clearcutting, mechanical sit preparation, and intensive silviculture treatments on water quality and quantity.  Specific objectives include:

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   TexIS (Texas Intensive Silviculture Study) Bulk Density Evaluation

    Two of the larger watersheds on the Alto Watershed Project site were evaluated for Bulk Density using GIS.  Mean surface (0-10) bulk density for LW4 was found to be significantly greater following harvest.  However, mean differences on LW4 (0.86 pre- to 0.95 post-harvest) were not high enough to negatively affect forest productivity.  No differences between pre- and post-harvest were observed on LW2.  Higher bulk densities were observed on logging sets after harvest, and mean values for sets were greater than the adjacent stand harvest area.  SMZ thinning had no significant effect on mean surface bulk density.  Bulk Density on primary and secondary skid trails were not significantly different from stand harvest areas on either watershed.   Additional measurements will be taken after site-preparation and planting to evaluate effects of stand establishment practices.  Measurements will also be taken a year after planting to evaluate attenuation after treatment.



  - Soil Carbon Monitoring Project with Dr. Kenneth Farrish

    The objective of this project is to evaluate changes in soil organic carbon due to afforestation of marginal farmland in east Texas.  In order to effectively monitor changes in SOC over the duration of the afforestation project, a baseline for SOC was needed.  In order to understand the spatial distribution of SOC before tree planting on the farmlands used in the project, baseline SOC values were displayed using GIS technology.

    A two ha sampling grid system was overlaid on aerial photographs of the properties.  GPS coordinates for the plot centers where determined in the GIS laboratory and located in the field using a GPS unit.  A steel post was set at each plot center.  Two soil samples, one 1m north and the other 1m south of the plot center, were extracted using a push probe to a depth of 40 cm at each point.  Each sample was dried at 70oC, ground to pass a 2mm sieve, and analyzed for carbon and nitrogen content on a Leco C/N analyzer.

    The GIS carbon model provided evidence of anthropogenic influences on SOC on these properties, probably due to manure spreading from the dairy operations.  The soil mapping units from the soil survey were not effective predictors of variation of SOC, probably again due to anthropogenic influences.  Total nitrogen concentrations are usually strongly correlated to SOC.  The Nitrogen models indicated that the relationship holds on these study sites.



  - GPS Accuracy Assessment with Dr. Daniel Unger

    The accuracy of two popular GPS receivers, the Trimble GeoExplorer 3 and the Trimble Pro XRS that were chosen for their common use and wide range in purchase price, are evaluated for use in natural resource applications.  With the increased popularity of GPS involved with natural resource management activities in recent years, and the wide range in purchase price of current units, it is imperative that the users understand the ability of each unit to accurately identify the true horizontal and vertical location of a surface feature.  It is the objective of this project to assess the accuracy of the two most popular GPS units used by natural resource professionals by comparing the distance between GPS derived points and their corresponding surveyed points on a time continuum (e.g. number of received satellite signals per surface feature location), to ascertain the relative efficiency of each receiver.

    Once their relative accuracy has been identified, natural resource managers will be able to save time and money by assessing the relative efficiency of each receiver based on a particular managers mapping, location identification and navigational needs by analyzing the cost and time involved to identify the true horizontal and vertical location of a surface feature.



  - The Spatial Variation of Floods with Return Periods Greater Than 100-year in the Conterminous United States with Dr. Mingteh Chang

    The goal of the project was to assess the spatial and seasonal variation of the most significant floods, maximum magnitudes, and flood-area relations in the conterminous U.S.  This was done by using:

The conclusion of the study:


  U.S. Forest Service

   - User Trails Utilized by Commercial Pack Stock on the Inyo National Forest with Keith Waterfall

    A user-created trail is any non-system path created by the passage of visitors, in our case commercial pack stock, which is discernible and would not likely recover within one year.  The commercial Pack Stations identified the trails that they use and/or used in the past that are greater than 0.25 miles.  Field work was then done to locate these trails and classify sections of the trail as being; an incision, trail widening, having vegetation and sod damage, trail dividing into multiple trails, water diverted onto the trail, or the section is in fine order.  A Trimble GeoXT GPS devise was used to log each section as a line feature.  Each section is then evaluated on its overall and potential condition being that 1 is that the general impacts are light to 3 being that serious resource problems are imminent and immediate attention is required.  Point data was also collected with the GPS to indicate specific problems found on the route being; a stream crossing, vegetation and sod damage, spring and seep crossing, and/or headcuts and nickpoints associated with the trail.  Each point had an overall condition factor as identified above.

    The primary goals of this project were to:

    Once a complete evaluation is done on the trails, the trail will be either approved for usage or not approved and commercial stock will no longer be able to travel that route.




Costa, J. E., 1987. A comparison of the largest rainfall-runoff floods in the United States with those of the People's Republic of china and the World. Jour. Hydrology 96(1987): 101-105.


Perry, C. A., B. N. Aldridge, and H. C. Ross, 2001. Summary of Significant Floods in the United States, Puerto Rico, and the Virgin Islands, 1970 through 1989. USGS Water Supply Paper 2502. 598 pp.