Counting on sheep
At a time when interest in managing forests in an eco-friendly way continues to grow, using sheep for vegetation control can be a viable solution.
By Tony Kryzanowski
The concept of a computer was developed by research scientists in a laboratory back in the 1940s, but it took Microsoft president Bill Gates to fully understand the potential of this discovery as a practical tool—in the form of personal computers or PCs—in modern society. Frequently, researchers stumble upon important discoveries. Yet they remain underdeveloped for years until society finds the proper set of circumstances where an application becomes timely. Given today’s growing concern in Canada about water quality, land management and the residual impact of herbicides, some industry people think it may be time to revisit organic methods of vegetation control on certain types of forest cutblocks. And it doesn’t get any more organic than grazing sheep.
Using sheep as a form of vegetation control—as an alternative to herbicides and manual brushing crews—is not unusual in north central British Columbia. But it remains a largely under-utilized tool in other similar forested regions. While it was a novelty when it first arrived on the scene in Canada in the mid-1980s, most marginal operators have since been weeded out, leaving a core of highly professional sheep flock managers.
At its height, there were about 60,000 sheep used in vegetation control in BC. Now it’s down to an estimated 15,000. Barb Marshall, a professional silviculture consultant who has also worked for the BC Ministry of Forests, works in the heartland of the sheep vegetation control region of BC, the Robson Valley/McBride area. With more than 20 years of plantation experience, she has witnessed the ebb and flow of sheep use in the province. Marshall believes that along with herbicides and manual brushing crews, sheep vegetation control is a feasible, environmentally friendly alternative.
A high level of environmental activism in that area of the province has also worked against the use of herbicides. She says the Robson Valley has wet areas with rich soil—a combination that creates a severe reforestation challenge for forest companies. “The aggressive vegetation can grow so dense that it competes for sunlight and nutrients,” says Marshall. “Also, vegetation press may deform conifer seedlings.” She says the main objective of vegetation control in her area is seedling survival.
Marshall has noticed quite a positive impact where sheep have been used for vegetation control versus areas where no vegetation control has occurred. “What I’ve seen in the areas where we had sheep grazing is that the tree growth is substantially better,” says Marshall. “The trees were bigger, straighter and there were more of them.” This additional fibre benefit is noteworthy, she says, because it helps to justify the expense; companies eventually realize greater volumes of better quality fibre, earlier.
Sharrow works for Oregon State University’s Department of Rangeland Resources and has been researching the use of sheep for vegetation control since 1980. That’s when the United States Forest Service launched a program to use sheep to control vegetation in Oregon’s national forests. The objective was to remove rank grass in order to improve elk habitat; second growth vegetation is much more nutrient rich. This wasn’t the first time that Oregon used sheep for wildlife enhancement.
In the 1940s, they were employed in a similar fashion on public lands to help improve the overall health of the blacktail deer population. The results were extremely positive, as the deer population experienced significant population growth, weight gain and much better health due to a much improved food source. Montegal Creek Inc, of Bluffton, Alberta, is a professional sheep vegetation control company owned by Georgia Edworthy and Allan Neville. The company has worked for a number of large BC forestry companies, as well as the BC Ministry of Forests, and owns about 800 sheep. It also rents sheep from the Sunshine Hutterite Colony near Calgary. The flock is a mixture of Dorset, Rambouillets, and Suffolk breeds that Edworthy describes as the “perfect cutblock flock.”
The breed mix is a combination of loose and tight foraging species. There are specific instances within the forest industry, she says, where sheep vegetation control is preferable to herbicide use. “All brush and weed methods increase sunlight and reduce vegetation press,” says Marshall. “However, sheep grazing adds fertilizer and may result in increased soil warming.” A flock of 1,000 sheep leaves about a ton of manure per four hectares, which Marshall calculates represents a $85 per hectare benefit to the company.
Furthermore, unlike cattle and horses—where seeds are simply redistributed through their manure—sheep do not deposit any seeds because of their digestive system. When compared with manual crews, who often have difficulty distinguishing small seedlings from competing vegetation, Marshall says that tree damage using sheep is “phenomenally low.” “Provincially, well below four per cent of our conifers have been negatively influenced by sheep.” Using sheep instead of herbicides or manual brushing crews to control vegetation in specific types of newly planted evergreen stands is also potentially the cheapest control method, according to an American industry expert.
Furthermore, sheep can sometimes make the difference in harvesting going ahead in areas where herbicide use is banned, unpopular or could spark expensive litigation. “What we’ve found in the US is that where sheep grazing is appropriate, it is less expensive than the other alternatives—herbicides and mechanical vegetation control—providing you have a fairly efficient system to begin with,” says Oregon State University professor Steven Sharrow.
He adds that sheep use is cheaper than herbicides, particularly when potential litigation costs associated with herbicide use are factored in. “We’d be the optimum choice in areas where there are herbicide restrictions, and also where herbicides haven’t worked,” says Edworthy. The company takes on two contracts per year, clearing between 350 to 400 hectares per contract. The season runs from late May to late August. The total amount of forested land grazed annually by BC sheep grazers is about 6,000 hectares. A flock of 1,000 sheep can remove approximately 75 per cent of competing vegetation on four hectares per day. This compares with about half a hectare per manual brush cutter.
Edworthy was recently invited to attend a conference in France that focussed on the wide variety of activities taking place in the world’s mountainous regions. She was shocked to hear how unique this method of pasture/forestry management is globally. “After listening to people from the Andes and from places like Morocco, we were the only country that was benefiting by integrating resources from three different government agencies,” says Edworthy. “It is the only program in the world like it.”
She promotes sheep vegetation control as the most environmentally friendly alternative and believes that companies should more actively use this vegetation control method as a sales tool when selling lumber into eco-sensitive consumer markets. It took extensive lobbying of both government and industry to establish this service in BC. “It hasn’t been a smooth ride,” says Edworthy. “Getting us out there was really difficult, but that was understandable.”
Part of the problem was coordinating the government investigation and regulatory process because it involved three separate ministries—environment, agriculture and forestry. One of the biggest initial concerns was health, specifically transmission of diseases and parasites between the wildlife and domestic animal population. Since those early days, however, an extensive health protocol has been established. “That hasn’t hurt us at all,” says Edworthy. “It’s expensive, but it has made our flocks better. They are stronger and healthier. It has resulted in better shepherds, too, because they watch their sheep a whole lot more closely.”
While sheep perform well in coniferous stands, they may not be appropriate in aspen stands, unless the objective is to control aspen competition to encourage conifer growth. According to species palatability tables provided by Marshall, trembling aspen is one of the most preferred foraging species for sheep. Both experts and contractors agree that from a public relations and cost/benefit perspective, it’s hard to argue against the usefulness of a professionally managed sheep flock for vegetation control in replanted conifer stands, in select applications. The BC government operates a website—www.for.gov.bc.ca/hfp/forsite/sheep/index.htm that provides information about vegetation control using sheep, as well as contractor and industry contacts.
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