Hoof rot

During a tour of Weyerhaeuser land, elk researcher John Cook said herbicides aren’t eliminating forage for elk.

When Krystal Davies moved herself and her horses to the Kalama area in March, she started noticing something on their hooves. Her 5-year-old horse, Tucker, had previously had only one abscess. 

“Since I moved up here, he’s had 10,” she said. “Typically, you’re not going to get abscesses in healthy feet.”

Davies, a farrier or horseshoeing expert, is among the growing number of people asking whether the use of herbicides on private timber lands is related to animals’ health. She lives adjacent to Weyerhaeuser Co. land she says was recently logged, and she used to ride her horses on the company’s property until she noticed the abscesses.

Davies, who calls herself “kind of a hoof geek,” started to do her own research about herbicides after noticing similarities between her horses’ hoof problems and those with elk that have hoof rot.

Hoof rot

Krystal Davies said her horses are getting more absesses since she moved adjacent to Weyerhaeuser land.

Davies is one of several people who have implicated herbicides during recent meetings about elk hoof disease. When Bruce Barnes of Vancouver asked for a show of hands during a hoof rot meeting in Longview in March, most of the people in the room indicated that they thought herbicides were a factor. Barnes has called for a moratorium on herbicide spraying on forest lands, an idea that hasn’t gone anywhere with state agencies.

Herbicide experts who are advising the state Department of Fish and Wildlife have said there’s no evidence that herbicides used on forest land have any direct harmful effects on elk or other animals.

“Anything people can’t explain they try to put it onto pesticides,” said Anne Fairbrother, a veterinarian who gave a presentation about herbicides to WDFW’s hoof disease scientist advisory board.

But some hoof rot activists, including Mark Smith of Toutle, think that even if herbicides don’t harm elk directly, they change the amount and type of forage for elk. That leads to nutritional shortages that make the animals more susceptible to disease, Smith said.

“We’ve logged the forest but they don’t mitigate the damage,” Smith said.

For timber companies, herbicide spraying is a crucial tool. A 2004 study by several foresters found that herbicide use dramatically boosts wood volume production on Pacific Northwest forestlands.

Timber companies spray herbicides on clearcuts to kill plants that compete with newly planted conifers for water, sun and nutrients. Spraying typically occurs one or two more times in the first few years after replanting.

“The biggest competitors we have are some of the grasses we have here,” Weyerhaeuser forester Mark Sheldahl said during a recent tour of company land for the Department of Fish and Wildlife’s hoof rot working group.

Hoof rot

Davies points out one of the absesses.

The companies used to burn newly logged areas but concerns about air quality prompted them to switch to herbicides in the late 1990s.

Sheldahl said the company uses several different herbicides. “Herbicides are very expensive, so the less we can use, the better,” Sheldahl said.

Vickie Tatum, a Florida-based toxicologist for the National Council for Air and Stream Improvement, said herbicides’ effect has been widely researched. “There is nothing in that body of research that suggests that any herbicide used in forests could or would have any relationship whatsoever to hoof rot,” said Tatum, who also participated in the Weyerhaeuser tour.

Fairbrother, a principal scientist with the Exponent research company in Seattle, agreed with Tatum that most studies show that herbicides are “practically nontoxic to mammals.”

However, the researchers both said that they aren’t aware of any study specifically concerning elk. “There hasn’t been anybody that has looked at elk and exposed them to herbicides and seen if they developed hoof rot,” Tatum said

It would be difficult from an ethical point of view to purposely give elk high doses of herbicide to see if they’re poisoned, Fairbrother said. “Doing a study with elk is orders of magnitude more difficult than dong studies on mice or rats,” she said.

Matthew Randazzo, the senior advisor to Peter Goldmark, the state Commissioner of Public Lands, defended the use of herbicides on state forest lands. Herbicides must undergo testing that shows that they attack metabolic pathways that exist only in plants, Randazzo said in an email.

However, Bob Ferris, a wildlife biologist and executive director of Cascadia Wildlands, called Randazzo’s assertion “the classic argument, but when you look at it it’s not exactly true.” Cascadia Wildlands is an environmental group based in Eugene that focuses on protecting old growth forests and wildlife.

Some herbicides, particularly atrazine, can affect mammals, Ferris said. Studies have shown that it suppresses animals’ immune systems and can turn male frogs into females. Still, atrazine, which is sold under several product names, is one of the most commonly used forest herbicides.

Herbicides’ effect short-lived

Elk forage recovered after herbicide treatment in less than two years after seedlings were planted, according to a paper published recently by Andrew Geary, a researcher at the University of Alberta who has studied elk nutrition at Mount St. Helens.

The overall effect of herbicide treatments on elk forage is “likely of short duration and probably has less impact on nutritional resources for elk than effects from widespread declines in timber harvest” in the Northwest, Geary wrote.

Generally poor nutritional conditions for elk are more of a problem for Mount St. Helens elk, which are generally in worse nutritional condition compared to other herds in Western Washington, Geary wrote.

John Cook, who has also studied elk extensively, has noted that elk eat only a small percentage of the plants that grow in forests. “It’s pretty darn bleak” for them, Cook said.

“The allegation that using herbicides is eliminating forage is not credible,” Cook said during the Weyerhaeuser woods tour.

Cook suggested that if people are concerned about elk habitat, they should focus more on forest practices on federal land managed by the U.S. Forest Service.

Private timberlands, which are logged and managed far more intensively than the Forest Service land, provide much better nutrition for elk even if they do use herbicides, Cook said. More frequent logging on private timberlands allows more growth of leafy forage that elk eat.

“Compared to federal public forest land, it’s a lot better here,” Cook said on Weyerhaeuser land. “The federal agencies are sitting on a potential gold mine of productive forage for elk.” Logging on federal forests has been substantially reduced since the Northwest Forest Plan of 1994, which was enacted in part to provide better habitat for the endangered spotted owl.

“How much do we have the right to tell Weyerhaeuser that they aren’t doing enough?” Cook asked the hoof rot group.

Cook and Tatum point out that herbicides are used across the Northwest and elsewhere in the country, but hoof rot has appeared widely only in Southwest Washington.

So far, at least, elk with hoof rot haven’t been spotted nearly as often on Forest Service land in Southwest Washington, where herbicides are rarely used. However, scientists caution that hoof rot spreads where elk are more closely bunched together, which happens more on lower-elevation private lands than in the national forest.

Conflict of interest questioned

Those questioning the use of herbicides point out that WDFW’s invited experts have been funded by the forest products industry.

Tatum said that NCASI, which she and Cook work for, gets suggestions for research from the timber companies that fund it. But she said the companies don’t try to influence the results of the research, which is peer-reviewed by other scientists.

Fairbrother works for Exponent, which does research on a variety of engineering and scientific subjects. Fairbrother acknowledged that Exponent works for pesticide companies, but said, “we provide an independent review and an honest answer for whoever asks.”

Geary’s research for the University of Alberta was partially funded by Weyerhaeuser and chemical companies.

Ferris accused WDFW of paying too much attention to researchers funded by the logging and herbicide industries.

“You need to get away from them because even if there isn’t any conflict of interest there’s an appearance of conflict of interest,” Ferris said.

Guy Norman, Southwest Washington regional manager for the Department of Fish and Wildlife, said his agency respects the scientific integrity of the researchers it works with.

Herbicide foes aren’t quitting

Barnes and Smith have been meeting with environmental groups and state officials to drum up opposition to herbicides. He also calls for testing the blood of live elk to see if there are traces of toxic substances — so far, the only elk tested have been killed so their internal organs can be examined.

“I think they know it’s these chemicals and they’re covering it up,” Barnes said.

Last week, the men asked the Washington State Forest Practices Board to review the state’s rules for aerial herbicide spraying and to ban atrazine, Roundup and other chemicals.

The board unanimously denied the petition, with members saying herbicide regulation is the responsibility of the state Department of Agriculture, not the Department of Natural Resources.

After the meeting, Barnes said he will bring the bring his complaints before that agency, too. “There’s obviously something wrong here,” he said. “What we learned today is there’s absolutely no oversight.”

“They think we’re going to go away,” said Smith, who’s running for Cowlitz County commissioner. “We’re not going to go away. We’re just learning.”

Davies, the Kalama farrier, suggests that the WDFW bring in a hoof expert to the hoof disease science team. “It completely confuses me,” she said. Meanwhile, she thinks caution is advised for spraying herbicides. “Avoid it not just for the known risks but the unknown risks.”

In a blog post, Ferris, too, said that WDFW needs to seek out a wider range of opinions about hoof rot and herbicides and do more research. “... there is so much that we do not know, yet we are acting in a manner that suggests we do,” he said.

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Tom Paulu is a features writer for The Daily News. He covers Outdoors and Entertainment, among other things. Reach him at 360-577-2540 or tpaulu@tdn.com.


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