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Browse Removal - Cole Browse Method


Written by Jason Karl

Method Type

Quantitative

Other Names

None known

Description and Uses

The Cole Browse Method is one of a set of methods for quantifying utilization that is specific for shrubby vegetation. This method collects data on browse species, age, availability and hedging, estimated utilization, and growth and use indices for the browse component of a plant community. From these data, estimates of annual utilization and utilization trends can be made.

Data for the Cole Browse Method are collected along transects. Separate transects must be run for the different browse species. Each browse plant along the transect is rated according to the following classes where available refers to accessibility to the animals and hedging is the appearance of being browsed or clipped:

Class #Form Class
1All available, little or no hedging
2All available, moderately hedged
3All available, severely hedged
4Partially available, little or no hedging
5Partially available, moderately hedged
6Partially available, severely hedged
7Unavailable
8Dead


In addition, Age class of each plant is estimated as is the percent of the leader (that year's annual growth) that has been browsed. Measurements of unbrowsed leaders are taken to estimate average annual growth.

The following information is calculated from the plants sampled:

  • Percent composition by form class,
  • Percent composition by age class,
  • Average leader use,
  • Use index (i.e., an indication of the volume of browse removed)

Confidence intervals can be constructed around median or average leader use, and statistical tests (e.g., Chi Square analysis) can be used to determine if age or form class proportions are different than expected.

Advantages and Limitations

The Cole Browse Method is usually faster than other browse utilization methods that require measurements. But, the gain in speed of implementation is typically accompanied by a decrease in precision. Variability between observers can be considerable, and factors like plant growth characteristics, and weather and site conditions can influence results.

The accuracy of utilization estimates using this method is heavily dependent on how thoroughly the observers have been trained. Observers need to be able to reliably: 1) identify browse species and age class of browse plants; and 2) recognize annual leader growth, percent utilization, and degree of hedging.

Manuals/Instructions


Image from Utilization Studies and Residual\\Measurements Interagency Technical Reference
Example of a filled-out Cole Browse form from the Utilization Studies and Residual Measurements Manual.

Technical and Application References

  • Bureau of Land Management. 1984. Rangeland Monitoring - Utilization Studies. TR4400-3.
  • Cole, C. F. 1963. Range survey guide, revised edition. Grand Teton National Park, Moose, Wy.
  • Eddington, D.B. 2006. Effects of cheatgrass control on Wyoming big sagebrush in southeastern Utah. Master's Thesis, Brigham Young University. (http://contentdm.lib.byu.edu/ETD/image/etd1606.pdf).
  • Howery, L. D. Ruyle, G. B., and J Hiller. 2007. Using herding and strategic mineral supplement placement to improve cattle distribution in west-central Arizona. USDA Research, Education, and Economics Information System. (http://www.reeis.usda.gov/web/crisprojectpages/204692.html).
  • Launchbaugh, K. [accessed 12/2009]. Techniques to determine utilization: Range 357 class notes. College of Natural Resources, University of Idaho. (http://www.cnr.uidaho.edu/range357/notes/Utilization.pdf).
  • Summers, D.D. Vegetation response of a Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis) community to 6 mechanical treatments in Rich County, Utah. Master's Thesis, Brigham Young University.

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field_methods/cole_browse_method.txt · Last modified: 2012/03/08 15:42 by jgillan