Black Hills Robel Pole Project
Explore, enjoy and protect the planet
This project was initiated in 2010 by the Sierra Club and joined in 2011 by Safari Club International.
The Gonzales property was purchased by the Rocky Mountain Elk Foundation and turned over to the Forest Service with the understanding that it would be managed for the benefit of wildlife. Shelly Deisch of SDGF&P measured residual vegetation with the Robel Pole and found it overgrazed. The Forest Service claimed it couldn’t find the memorandum of agreement (1994) regarding the property, but were managing it appropriately.
The Forest Service entered into an agreement with Western Watersheds, Biodiversity Conservation Associates, the Sierra Club and SDGF&P regarding management of Gonzales promising to honor the MOU and graze Gonzales and another RMEF purchase, Bessant Park, only when required to enhance wildlife values. In addition the Forest Service agreed to graze the Tilson parcel for no more than 10 days and less if the utilization limit of 50% was reached.
The difference in allowed forage use between a pasture in good condition and one in unsatisfactory condition is only 5%. This is far below the ability of the Forest Service to detect in the field—or for the much more sensitive methods employed by the Sierra Club, for that matter. Deferred rotation means the cows are moved through several pastures during the same season. Rest rotation means one pasture in the rotation system isn’t grazed at all.
Forage is not the same as total vegetation. It includes only those species that livestock normally consume. To measure utilization directly one would have to fence cattle out on a number of sites of a pasture to be measured. Then, after grazing vegetation within the fenced areas and adjacent grazed would have to be clipped, sorted by species, dried and weighed. This method is totally impractical, thus in practice indirect measurements, of which several exist, are used.
The method of annual use monitoring employed by the Black Hills National Forest is almost always the “Ocular by Plot” method. The observer walks a line called a transect and compares the vegetation at several stops to the descriptions in the table. Note that the categories are of unequal width.
In this example, the data from the various categories are combined into an overall measurement. Because the categories are not of equal width the utilization formula is mathematically incorrect.
The Northern Hills Ranger District range staff admit that they do not do the required training, nor do they do multiple transects required to establish statistical reliability.
With utilization management, in drought, very little residual vegetation is left at the end of the grazing season. Management based on residual always leaves the same amount of residual vegetation, wet years or dry.
The Robel pole is a residual based monitoring method. It’s accurate, precise, and simple in application. And it is objective while the Forest Service's method is totally subjective.
The Robel pole has been calibrated specifically for the Northern Hills.
Daryl Mergen, Ph.D. Range scientist and co-author of the Robel pole paper. Dr. Mergen received a grant from the Sierra Club and Safari Club International the first year and in the second served as consultant, data analyst and volunteer trainer.
By measuring the height and density of the standing crop of vegetation, the Robel pole, when calibrated, can determine the standing crop for a pasture. This is helpful in comparing residual-based management to utilization. We took over 8,000 individual measurements each year during this study.
The bar on the right is 50% of the mean of several ungrazed pastures. The remaining bars represent residual vegetation following grazing. The red parts of the bars represents statistical uncertainty. The fact that none of the red bars of the grazed pastures overlaps that of the ungrazed indicates every grazed pasture was grazed beyond guidelines. One of the most heavily grazed was the Tilson pasture which was mentioned as one the Forest Service had agreed to manage better.
Uresk, Mergen and Benzon recommended a guideline of 10 Robel pole bands. Only one of the grazed pastures met this guideline. Despite this statistically powerful data set and the weakness of their own, the Forest Service disputed the Sierra Club’s findings claiming that the Robel pole can’t be used to estimate utilization and that Sierra Club measuments were not on their key areas. While the Forest Service was disinclined to credit our study, they attempted to suppress further research by stating that we required a special use permit in the amount of approximately $1,000 to conduct further research.
2011 Data. Responding to Forest Service criticism that the Robel pole doesn’t measure utilization, we clipped vegetation both before and after grazing on a number of pastures. Bars where the bottom of the red zone is above the 50% line are significantly overgrazed. Note that the red zone, the zone of uncertainty, is 15-20% making detection with statistical certainty somewhat difficult. Nevertheless, we can state with certainty that some pastures were overgrazed in 2011.
The Greens Gulch pasture had cattle present every time we visited it. Scheduled for only 30 days cattle were present at least 60 and possibly as many as 120 days.
The table is a test of whether or not overgrazing is a problem on the Northern Hills Ranger District overall. The low p-value indicates that it is.
Using the recommended residual limit of 10 Robel pole bands, about 75% of the pastures were overgrazed.
This is the Buskala Rod and Gun pasture. Most of the pastures on the Northern Hills Ranger District have been abused to the extent that native grass species have been totally replaced by invasives like timothy, smooth brome and Kentucky wheat grass. On a few pastures even the invasive grasses are being supplanted by broadleaf weeds like the ox eye daisy you see here.
OK, the cows are taking more than their allotted share of forage, why should you care? If you hunt, fish, hike, camp watch birds or wildlife, or drink the water you should care. Lest you think that non-commercial uses of the forest are not economically significant, this Forest Service commissioned study of the Bridger-Teton shows that the value of hunting and fishing alone exceeds that of livestock grazing.
Have you seen those bumper stickers that say, “I want my country back”? Now you know who has it--the commercial interests and the government that is supposed to be regulating them. To sign the petition go to http://www.change.org/petitions/halt-livestock-overgrazing-on-the-black-hills-national-forest. For more information, contact Tom Juntti at email@example.com.