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Noxious Weeds: Stemming The Tide
Explosion in Slow Motion
(presented at Stemming the
Tide, a BMNRI seminar)
by Jerry Asher, Natural Resource Specialist, Bureau
of Land Management, Portland
The first purpose of this presentation is to raise the awareness
about rapid spread of these weeds and the impact of them upon our
lands. The second purpose is to explain how we can all use the successful
wildland fire management thinking process to combat these weeds.
There are some identical situations when it comes to managing weeds.
Many of us know how to manage fire. Noxious weeds have taken away
or severely impaired our ability to manage for healthy rangelands
and ecosystems of millions of acres of federal lands in the Northwest.
In fact, the weeds continue to expand rapidly. We have an explosion
in slow motion underway right now.
The good news is there are many economical and effective measures
we can use to control these weeds, and there are many thousands
of people who are eager to help us.
There are many fine people who have been attacking these weed problems
in the West for some timeBLM, Forest Service, counties,
state, highway deptartment, and private landowners. They really
deserve a lot of credit and they've had a lot of success.
There is complete and uniform agreement among the university science
departments, Agricultural Research Service, Department of Agriculture,
experts in the Forest Service and BLM that the weeds are indeed
expanding rapidly. There is no criticism intended in the story I
will tell. It is my best attempt to explain the situation the way
There are many others who know more about controlling a specific
weed than I do, and I recognize that. The goal is to reduce the
spread of weeds. I'd like to bring a little reality into the room.
I have a bouquet of yellow starthistleit has been microwaved
so I'm not spreading viable seeds. We will be seeing pictures of
leafy spurgethe worst of worst weeds. Even though it
is relatively easy to control in the first couple of years, after
that it will send down very deep roots; if the soil profile is deep
enough it will go 20 feet below the surface. It sprouts readily
from 8 feet below the surface and translocates herbicides poorly;
therefore if you get patches of it on a hillside, nobody knows how
to get rid of it. The nodules are places where it sprouts and the
roots tend to marry up below the surface and really take over the
Most of my stories are about federal land in the West, but weeds
don't pay any attention to boundaries. Managing for rangeland ecosystem
health depends on a wide variety of grasses, forbs, shrubs, and
trees. Air, water, and animals are also very important components
of the system, but if the vegetative components are functioning
properly, those other components will also function properly. Therefore,
recognizing the often permanent damage to these plant communities
by noxious weeds, these weeds are the single greatest obstacle to
managing for rangeland health on much of the western wildlands.
The spread of these weeds began a few centuries ago, but primarily
in the late 1800s when people, especially from Eurasia were coming
here, and many purposely and accidentally brought plants with them
from the home country. Now these weeds were not invasive in the
home country, because they evolved over the millenia with the complement
of insects, disease pathogens, and competition from other plants.
But once brought to this country and released from those controlling
factors, they are very aggressive.
Population studies on BLM lands alone showed that in 1985 we had
about 2.5 million acres of these weeds, in 1994 about 8.5 million.
We know they increase about 14 percent per year. Therefore, by the
year 2000 we expect to have between 15 and 20 million acres if we
don't increase our weed management efforts. Also, that 14 percent
figure tells us they are increasing at about 4,600 acres per day
on western federal lands.
So what? These weeds often create monocultures, blocking our ability
to manage for biodiversity. Some are poisonous. They are painful
and injurious to recreationists. There is loss of livestock and
wildlife forage and habitat and increase in erosion. They outcompete
rare native plants and reduce adjacent private land value. And they
are indicators of and contributors to desertification in eastern
Oregon. A 1,300-acre ranch near Klamath Falls, Oregon, is mostly
leafy spurge. The ranch was abandoned in 1989, went on the auction
block, and sold for less than 10 percent of what it would have otherwise.
The following year it was taken off the tax rolls. Severe reductions
in livestock forage can occur. Recreation sites are abandoned because
of severe infestation. Weeds can outcompete the vegetation wildlife
need for survival.
In the 1800s, yellow starthistle found its way from a foreign country
into the San Francisco Bay area, spread into northern California
and in the last 15 years has spread from I million acres to 10 million
acres in northern California. It then spread into southern Oregon
along the Klamath River. There is a substantial population south
of Mitchell, Oregon, making the surrounding lands at risk of invasion.
At a site a few miles north of Lewiston, Idaho, yellow starthistle
was first identified in 1938. The danger was not recognized, and
today it infests hundreds of thousands of acres in southern Washington
and Idaho blocking our ability to manage for healthy rangelands
and biodiversity. In today's technology, on steep slopes it is impractical
or not economical to restore those sites. Primarily in the last
8 years, the amount of land in the BLM Cottonwood Resource area
that is now infested in yellow starthistle is approaching 30 percent.
An explosion in slow motion!
In Nature Conservancy lands, habitat of the rare Calichortis plant,
found only in the Hells Canyon Area, is being attacked by yellow
starthistle. On the Salmon River, the area manager explained that
yellow starthistle has taken away his ability to manage the area
of critical environmental concern.
Yellowstar, before it flowers in late June or early July, can be
identified in the distance by its green cast. Many of our valuable
lands in the lower Salmon and Snake Rivers are becoming infested
by yellow starthistle affecting elk range, critical deer winter
range, bird hunting, watersheds, and salmon habitat. To the north
on the Oregon/Washington border, yellowstar has increased over 100,000
acres in the last 30 years. Yet, it has just begun to infest the
hundreds of thousands of acres susceptible, and we are doing little
to control it.
Another big problem weed, leafy spurge, is almost impossible to
get rid of after the first year or two. There have been a few small
patches found on the Grande Ronde River in recent years. It's in
BLM land in Klamath County; every time folks go out they find some
more. We need to get on top of those small patches. They like to
become bigger. In today's technology, it is either impractical or
impossible to restore a site once infested with leafy spurge.
Whitetop. We need to find the small patches and control them because
they like to become larger patches. In Baker County, whitetop is
going up the draws; it was not there 13 years ago on the critical
deer winter range near Keating.
Rush skeletonweed was so named because of the almost complete absence
of leaves. It was first found in Banks north of Boise in 1954. In
1964 there were 40 acres; today there are over 4 million acres.
Baker County has one patch. Union County has one patch. Thanks to
the Department of Agriculture, those are under control. Where they
are just moving in they are very manageable at that point.
Squarrose knapweed is like other knapweeds except that the seed
head is smaller, and it has down-curved bracts like a cockleburr.
The seedhead easily breaks off and clings to clothes and animals.
Squarrose likes a wide amplitude of growing conditions. Near Tintic
Junction, Utah, it was first noticed in 1954. Now it occupies 140,000
acres leapfrogging across the desert. It continued to expand during
a drought. It also likes the ponderosa pine type.
Diffuse knapweed is a problem in the wilderness near Prineville.
Spotted knapweed has a beautiful purple flower. Montana has over
4 million acres of spotted knapwecd, and it continues to expand
there as well as in Idaho, Washington, and Oregon. It was first
noticed in Northern Nevada in 1993. Those are a few biocrises in
These weeds really prefer disturbed sites; that's where they get
established and grow fastest. Recreation sites, highway right-of-ways,
overgrazed areas, mining areas, forestry activity areas; that is
where they become established. Healthy communities with desirable
vegetation and good husbandry of the land is our first line of defense.
However, we need to recognize that as the recent scientific literature
describes and my pictures show, they also appear in some of the
best lands. We don't know that they are necessarily taking over,
but they are certainly moving into some of our best land.
For example, in the heart of the Sellway Bitterroot Wilderness,
estimates range up to 40,000 acres of spotted knapweed. There was
no livestock grazing there in over 50 years; much of it was never
grazed; no logging, no mining. So we have an excellent learning
laboratory of what can happen in these conditions.
I found a slope dominated by spotted knapweed above the Selwood
River, which has prime salmon habitat. With an infestation like
this, you get an increase in sedimentation. It is spreading rapidly
there and other places after fire. The Ranger would love to be authorized
to send in a crew for 2 or 3 years in a row to search out that spotted
knapweed and keep it under control while the native vegetation reestablishes
itself. And if he were authorized to do that, it would cost a mere
pittance of what is spent to put the fire out.
At the mouth of the Grande Ronde River in 1993, we accidentally
found a few yellow starthistle plants, some tall whitetop (the closest
are 10 miles away), and one spotted knapweed (the closest 20 miles
away). These tiny infestations were controlled, but in 1994 we went
back to check and found new populations of rush skeleton weed. The
point is, those were found accidentally. We all need to get organized,
in agencies and others, so that people are trained to recognize
the weeds. There are a lot of eyes out there, and if they just understand,
they can report weed sightings so we can control them while they
Figure 1. Purpose: To emphasize the importance of immediate
After arrival into an area, weed infestations often remain quite
small for a number of years, producing seed but not expanding significantly.
Then, when conditions are favorable, exponential growth often occurs.
We must minimize the time between introduction and detection so
inexpensive and effective control is possible.
Mediterranean sage is expanding rapidly. New weeds are coming all
the time. Sulphur cinquefoil can be found near Minam and is on the
increase in Oregon. Dalmatian toadflax was found along the Lower
John Day River along with diffuse knapweed. Medusahead, once we
get a severe infestation of it, is so difficult to get rid of. In
areas where it is just beginning to show up, it is quite manageable.
Purple loosestrife will devastate the wildlife habitat of our wetter
areas. It grows even in areas of Utah and is rampant in wet areas.
Some weeds can spread very rapidly. In 1993, Pittsburgh Landing
in Hells Canyon was surveyed by weed experts who found no noxious
weeds. In 1994 there was a wall of purple loosestrife on that site.
We really need to have people trained and alert because these things
can happen fast. We need the public trained to help identify them.
The Wilderness Act tells us to manage for the community of life
untrammeled by man, and that natural conditions should be preserved.
We have two other laws that direct us to destroy noxious plants
and to establish and adequately fund an undesirable plants management
First, recognize that most of the public land does not look like
the ugly pictures I showed. That was a concentration of the worst
I could find to make the point of what can happen and the direction
things are going. We have vast areas where weeds are just arriving,
and they are easily controlled at this stage. In fact, approximately
95 percent of the public lands are not yet significantly infested.
So we can get at managing these lands by using the fire model of
prevention, coordination, control, and containment. AlI the tools
including herbicides and biological controls are very important
and can be used in conjunction with each other depending on the
situation. However, preventioneducation, training,
and inventory with everyone working together for control of the
small outbreakscomes first because it is the cheapest,
easiest, and most effective. However, therein is the greatest challenge:
to get enough of the key people, landowners, and agencies, to put
that kind of energy and effort up front before it's too late.
The curve (fig. 1) illustrates that by the time lots of people
recognize the problem, it has expanded beyond the stage where it
can be easily controlled. There is only about 5 percent of the public
land at the top of the curve where the weeds are widespread. But
guess where we spend most of our effort. It is good that we are
attempting to control the seed source to protect other lands, but
we need a much greater effort at the bottom of the curve to minimize
the time between introduction and detection so we can use the cheap
and easy techniques to protect the 95 percent of the land not yet
Another big reason why we need to operate at the bottom of the
curve is that if we let the weeds get to the top of the curve, we
are going to need lots of herbicides and biological control agents,
which are commonly either not practical, not effective, or not available.
There are people who are encouraging us to do that. "When
concern rises, the battle is lost," says Tommy Gooch, Idaho
Falls BLM District.
We can use the presuppression and initial attack fire model to
think about it: prevention, training, detection, and initial attack.
In prevention, we can train employees, educate the public, teach
school children, and review our authorized activities. In detection,
we can do aerial surveillance, use global positioning mapping, and
ask employees and the public to report weeds and recognize the importance.
Initial attack includes spotting infestations and giving priority
to controlling small spots quickly, and rechecking infestations
repeatedly for control.
We need to inventory, because if we are to fight the enemy we need
to know where it is. With a trained eye and binoculars, one can
spot patches over large areas.
Weeds are spread by vehicles, wildlife, livestock, pantlegs, wind,
water, and equipment. Knowing that, we can undertake various management
activities: quarantine hay, remove weeds from gravel pits before
distributing gravel, clean weeds from entrances to wilderness areas,
train and ask recreation workers to control weeds along with their
other duties, train managers who work routinely in the field to
recognize and report or control weeds (BLM alone has 5,000 field-going
employees), cordon off weeds in fire camp so they aren't spread
by firefighters, ask "adopt-a-highway" groups to identify
and report or control weeds.
Control includes hand-pulling with some species, herbicides, and
continued monitoring. On some sites it also helps to replace removed
weeds with desirable species. In canyon areas, some folks are using
mules and a hand wand to apply herbicides selectively. Where there
is a will, there is a way.
Of course we need to work together, and an outstanding guide is
the Guidelines for Coordinated Management of Noxious Weeds in
the Greater Yellowstone Area produced by BLM, USDA Forest Service,
and Park Service. It describes detailed steps for coordination among
federal agencies, counties, and the states.
Who is responsible in the public agencies? Everyone. All activities
spread weeds and all activities should share in funding weed control.
For a cooperative effort to be successful it takes somebody to
step forward and be the catalyst.
The Tri-County Weed Management Area has just formed in Union, Wallowa,
and Baker Counties. There are two other proposed Demonstration Weed
Management Areas in the Northwest. The Idaho-Oregon-Washington area
surrounding the Snake River includes Forest Service, private, BLM,
and Nature Conservancy areas. The need is there because that area
has outstanding resource values, and the weeds are moving in: skeletonweed,
yellow starthistle, leafy spurge, purple loosestrife, and spotted
knapweed. Another demonstration area is proposed for the John Day
River System. So far they are only ink on paper, and we hope they
will be implemented.
You may be feeling overwhelmed; it is a big topic to consider all
weeds everywhere. On a local watershed basis, working cooperatively,
reaching weed management goals can be rewarding and reasonable.
If we can stop fires, surely we can spend as much energy stopping
weeds. Nature often helps us put out firesit doesn't
help us put out the weeds. Fires are often helpfulweeds
are never helpful. Negative effects from fire are usually short
term; negative effects from weeds are long term. So if we are to
invest in avoiding permanent damage to our lands, weed management
deserves just as much, if not more, attention as stopping fires.
For about 5 to 10 percent of what we wisely spend each year just
getting ready for fire, we could stop the spread of most
of the weeds on most of the places we want to.
In conclusion, we need to move rapidly and cooperatively to reduce
the spread of weeds.
To get involved, contact the Pacific Northwest Exotic Pest Plant
Council, c/o Lou Whiteaker, 2795 Anderson Ave, #25, Klamath Falls,
Characteristics of Noxious Weeds: The Ultimate Biological Pollutant:
- Native plant communities are often permanently changed.
- Many wildlife species are adversely affected both directly and
- The appearance can be deceivingly attractive and desirable.
- Only a few ounces of the pollutant can regenerate tons of itself
in only months.
- Its spread is predominantly by almost invisible means: seeds.
- The pollutant is spread by wildlife, livestock, recreationists,
wind, water, vehicles, and other equipment.
- The initial contamination and propagation are inconspicuous,
noticed only by experts.
- Increased erosion, increased fire hazard, and reduced water
quality are a direct result of infestations.
- New varieties continue to arrive.
- The public is largely unaware of the potential and actual damage
attributable to the pollutant.
- Weeds have the ability to lie dormant and undetected underground
for years, then reappear and spread.
- The manager's ability to manage for biodiversity and ecosystem
health is thwarted and often blocked totally.
- Threatened and endangered plants are especially vulnerable.
- Contact can be toxic, painful, and injurious to humans.
- The effects are often not apparent until the spread is already
out of control.
Noxious Weeds: Stemming the Tide
The Blue Mountains Natural Resources Institute presented a seminar
series on noxious weeds in May of 1995 at Eastern Oregon State College
Ed-Net. The broadcast was viewed at Pendleton, John Day, Enterprise,
Baker, Ontario, Burns, Heppner, Mitchell, Monument, Halfway, Prineville,
Lakeview, and Seneca, Oregon, and Walla Walla, Washington. This
special issue of the Natural Resource News includes material presented
at the seminars or as submitted by the speakers in written form.
Other sponsors for this series included Bureau of Land Management,
The Nature Conservancy, Union County, Umatilla County, Crook County,
Morrow County, Ochoco National Forest, Oregon Department of Agriculture,
Oregon State University, and Eastern Oregon State College.