Secrets of Strength and Beauty
Right-of-way and public vegetation management strategies.
Beaten down by unexpected traffic and enduring unforgiving exposure to the elements, vegetation in public and right-of-way areas must be strong and durable and, at the same time, aesthetically appealing. To successfully manage these landscapes is to work both with and, at times of weed and seeding control, against nature. Choices made by individuals in each state affect millions of residents, and these decisions must be made with caution.
Wisconsin: Working With the Prairie's Natural Support System
Right-of-way areas provide harsh living conditions for most vegetation. Vegetation along roadsides, for example, needs to be able to handle unexpected traffic and dramatic sloping along highways in some areas. Wisconsin's Department of Transportation (WisDOT) has found that the best way to tackle these challenges when choosing vegetation in these areas is to go native.
"We use native species of trees and shrubs as much as possible. Most of our standard grass seed mixes have consisted of the typical Eurasian sod-forming species such as bluegrass and fescues, along with some others," says Dick Stark, landscape architect for the WisDOT Bureau of Highway Operations. "Recently, we have been moving toward using more native grasses, with wildflowers in appropriate places where they would provide a show of color. Whatever we use needs to be able to thrive with little or no maintenance."
Because the state can become snow-covered for months during the harsh northern winter, "Salt tolerance is also an issue along the shoulders," Stark explains.
The department manages approximately 150,000 acres of roadside vegetation along about 12,000 miles of state and federal highway. "WisDOT is responsible only for state and federal highways," notes Stark. "We have no jurisdiction over county or town roads."
When landscape suffers along a system this long, maintaining it properly can be costly. "In calendar year 2003, we spent almost $5 million on mowing, almost $4.6 million on controlling woody vegetation, and just over $1 million on controlling the noxious weeds that we are required by state statute to control," says Stark. "There are three species listed in the statutes: Canada thistle, leafy spurge, and field bindweed. Our efforts are directed toward the thistle and spurge; bindweed hasn't really been a problem on our rights of way."
The best way to save money when it comes to vegetation management in public and right-of-way areas, recommends Stark, is to complete the job correctly the first time. "This requires attention to details such as preparing an adequate seedbed, using the proper equipment, seeding at the appropriate time, and so on." Using native plants can help in this respect, as well. Self-regeneration among the pre-existing species not only helps with costs but also can have a two-fold affect on improving the area's ecology.
"We have had a limited mowing policy in place since the early 1960s, which has allowed native trees, shrubs, grasses, and wildflowers to regenerate themselves on our rights of way. This also provides habitat for wildlife," says Stark. "Vegetation is also the most effective erosion control method there is."
A natural look is key to the state's public landscape. In fact, Stark says that vegetation in roadside areas is largely left "unmanaged," with some exceptions: In addition to controlling noxious weeds, WisDOT mows the shoulder of the road and, "for vision where necessary," controls woody plants that could grow to more than 4 inches in diameter in this clear zone.
"We use Transline for thistle control and Plateau for leafy spurge control," Stark says, referring to herbicides. "We also use Roundup or Roundup equivalents and Garlon products." Habitat, another herbicide that attacks invasive species, was used on a state highway project this summer.
Because of this policy of limited mowing, Stark notes, wildflowers have increased in number along Wisconsin roadsides. "We get many compliments on our wildflower ‘plantings' in areas where we have never done any wildflower plantings."
Proliferation of a different type of vegetation has caused some concern, however. "We seeded many, many acres of crown vetch for erosion control, particularly on slopes, from the late 1960s into the early 1990s," says Stark. "It grew so well that it has become invasive, moving across the fence into natural areas to the extent that we are now getting requests from our Department of Natural Resources to remove it in some areas."
With the help of a handful of hired contractors, the state is working on a project to improve the natural landscape in public areas by selectively destroying the species that threaten it. "While doing a vegetation inventory several years ago, we identified several high-quality native prairie remnants," says Stark. "Over the past three to four years, we have hired contractors to intensively manage some of them, to restore them as much as possible to their original state by removing invasive weeds and woody vegetation. We hope to continue this work in the future, although the work will be on a three- to five-year cycle, much less intense than the recent contracted work."
This prairie restoration project has been successful in part because of the use of prescribed fire.
"We have also burned a few other areas using WisDOT staff and county highway maintenance crews, sometimes aided by Department of Natural Resources fire crews," says Stark. "We feel that it is an excellent tool that must be used cautiously and judiciously."
Improving Ecology in Oklahoma
While vegetation management in public and right-of-way areas is funded by the state, in Oklahoma, communication with area residents and smaller municipalities is an important part of the Oklahoma Department of Transportation's (ODOT's) mission.
 Photo: NTech Industries |
Agreements are worked out within cities to determine which public landscapes the smaller authority will care for and which the state will manage, explains Michele Dolan, stormwater coordinator for ODOT in Oklahoma City. Ongoing communication with treatment area residents also helps the department avoid conflicts. "If the landowner asks us not to spray, then we won't spray on their property," says Dolan.
Herbicide treatments, primarily Roundup used in various combinations, are typically applied to state-managed public and right-of-way areas twice annually. Herbicide regulations differ from state to state. As prescribed fire is not used as a vegetation management method in Oklahoma, herbicide use is combined with mowing, which varies depending on the climate. In non-urban areas, says Dolan, the state typically mows three times each year.
ODOT has purchased NTech Industries' WeedSeeker automatic spray system, which can help manage weeds by singling them out to eliminate them, using less herbicide and saving additional time. "[It] recognizes chlorophyll," explains Kathie Checkal of NTech Industries, based in Ukiah, CA. "When it sees the green in a weed it just sprays on that weed only. It cuts herbicide use way down, 50% to 90%."
ODOT manages 31,057 miles of roadway and maintains approximately 111,000 acres of right-of-way areas. Slope and soil types are the primary considerations when purchasing vegetation for harsh conditions in some public and right-of-way areas. An active roadside wildflower program using donated seeds is part of the state's beautification program and helps keeps costs down.
"Most of the soil in Oklahoma is really clay or really sandy," says Dolan. "We grow a lot of weeping love grass and buffalo grass and blue stem grass."
Bermuda grass is a popular choice for roadside shoulders throughout the state, particularly for its ability to handle stormwater runoff well. "The roots help hold the depth of the soil there, but the upper part of the plant stops the impact of the raindrop," explains Dolan. "[The plant selected] has to be something you can maintain without killing, and it has to be something that will handle flow. It has to have a real tight root system. Bermuda's great."
Improving the ecology of the region is a goal ODOT strives to meet because, according to Dolan, vegetation management can reduce erosion, provide habitat, produce oxygen, and please residents aesthetically.
Beauty and Power: Maintaining Rail and Utility Line Landscapes
Since ancient times, getting beauty and power to peacefully co-exist has been challenging. Railways, symbols of industry, offer landscaping design challenges to those responsible for their maintenance.
 Photo: Pennsylvania DOT |
"In the railroad market, there are specialized equipment needs beyond those necessary for roadside applications," says Bill Nichols, territory manager for the State of Michigan for Townsend Chemical. He explains that these needs include trucks equipped with high rail units that allow workers to remain atop the rail as nozzles attached to the truck spray herbicides to either side of the tracks.
Todd Horton of BASF Vegetation Management Group contrasts the needs of maintaining vegetation near roadsides and near rail lines: "In the South, they actually want desired turf. In South Carolina, they use Bermuda grass," he says, explaining that herbicide applications can be used to maintain vegetative height. "They want clear sight lines around corners. They go for low-growing turf and try to manage with that in mind. This is in contrast to something like a railroad and utility [areas] where they have to have total vegetative control. Vegetation can destroy the integrity of the rail line."
Another type of roadside vegetation manager, he says, "wants to control everything but a particular plant. The same herbicide can be used for releasing a desired turf. It all has to do with the amount of herbicide put out. You may put out 3 or 4 ounces of an herbicide to release a species. Twelve ounces may control a species."
Vegetation management at rail lines, as with most public sites, depends on the slope involved. "For relatively flat areas and moderate slopes, hydraulic mulches with native mixes or grass can be used," says Sam Morris of Phoenix Paper Products, based in Lostant, IL. "For more severe slopes or moderate slopes with high water-flow potential, bonded fiber matrix [BFM] products or erosion control blankets can be used. BFM products are also used when there is a lengthy time between seeding and germination, as in some of the arid regions in the western part of the US."
The business of stabilizing slopes begins at the root of plants chosen for the job. "Any vegetation will help to stabilize slopes, but vegetation with deep, fibrous roots will do it best," says Stark. "Not only do these roots provide slope stability; they also aid in water infiltration."
Performance concerns often exceed aesthetics when in comes to caring for areas housing utility lines. "Appearance plays a small factor in most jobs," says Morris. "The most critical criterion is performance based upon the objectives of the particular site. From a practical standpoint, you do not want any unnecessary foot traffic on any revegetation project until the vegetation is well established."
Woody vegetation control is a primary consideration with utility lines. "They [vegetation management workers] want to control just the wooden vegetation," notes Horton. "They can also use selective application techniques."
During his decade in the industry, Horton has seen what he terms a dramatic shift toward looking out for what's best for the environment. Manufacturers of vegetation management products are required to produce more studies than when he began his work.
"We've seen a trend over time: Mechanical methods of vegetation management, over time, are more expensive than herbicides," he says, providing an example of a utility that mows down brush; seven years later, there might be nine stems where there once was only one. "The costs add up. With herbicides you can actually go out there and change the [environment] you're working with.
"There's a big buzzword in the industry: ‘integrated' vegetation management," he continues. "Basically, what that is is looking at a given site, using a combination of mechanical and herbicide methods, and using biological control methods such as insecticides. It's using all those tools to accomplish that objective that you want."
Electric utilities must eliminate plants that could cause outages, he explains, while at the same time they want non-threatening vegetation to thrive to protect the slopes where lines are set up. This is part of many states' battle against erosion in what can be remote right-of-way areas.
Groundcover in Pennsylvania
Being the Keystone State can be difficult when it comes to looking good. Pennsylvania's highways connect northbound travelers from the south and the west with New England. That means there is heavy traffic on both sides of approximately 40,000 miles of highway. Roadside vegetation must be selected to perform.
Photo: Pennsylvania Department of Environmental Protection |
John Whaley, landscape design supervisor for the Pennsylvania Department of Transportation (PennDOT) based in Harrisburg, says that while the slope, soil, and amount of light available ultimately determines the plants that are chosen, PennDOT frequently uses a Kentucky 31 tall fescue, which he describes as a tough grass that can handle some vehicle traffic without causing erosion.
"It can be maintained by growing to various heights," he says of the fescue. "Pennsylvania has used crown vetch, a leguminous-type plant that will grow in a wide variety of soils. It's been very adaptive to cover a wide range of subsoils that are often encountered in roadside areas. It also replenishes the soil with nitrogen."
Crown vetch provides good groundcover, explains Whaley, while not permitting larger tree growth close to the roadside. "What we have noticed over a few years is that the crown vetch eventually is going to thin out and other things come. We're to get 15 to 30 years in some areas where that crown vetch will remain a good groundcover for us."
Saving money is an issue that can arise for even the most well-funded state transportation departments. In fiscal year 2003–2004, PennDOT had a budget of $30.9 million, with about $7 million designated for mowing, $5.7 million designated for varieties of herbicide control, and $18 million allotted for tree and brush removal. Whaley says the department is working to reduce costs by trying to mow less and add long-term vegetation, including native grasses, wildflowers, and crown vetch. To save money, he says, vegetation managers must be aware of the maintenance involved in the materials they choose.
Herbicides need to be used at an early stage to keep tall vegetation from moving toward the roadside, explains Whaley.
"If you want to keep it a grass, you want to consider the mowing costs and also keep it in condition"—in other words, you don't want to allow "invasion by broadleaf weeds or volunteer woody plants," he says. "The more you mow, the less you have of that type of problem. Are you going to mow once a year or twice a year?"
While trees and shrubs are also used in public and right-of-way areas, most research with herbicides comes about because of the large amount of maintenance involved with managing grasses. PennDOT has been working with Pennsylvania State University researchers to determine how best to manage roadside vegetation. The researchers study many aspects of the work, including the length of time between mowing for the best results, as well as the effects of herbicides.
"We feel it's been well worth the money for them to make recommendations on different roadside vegetation management practices. It's a slow process, but we feel like we are making headway [and finding] an integrated approach to the problem," says Whaley. "The Penn State researchers have been looking at a number of types of mechanical equipment to apply less herbicide safely. That may take several years of looking at how the equipment is evolving and how much it costs. We're still finding the mechanical approach to cutting and putting on herbicides is slow and may not give us the control that we would like. We still feel spray equipment with various nozzles that they can use to control the spray pattern and amount of chemical applied is the least costly and most effective. The most expensive is the backpack [application]. That's very costly and time-consuming in man-hours."
All roadside herbicides have to be registered for roadside use, notes Whaley, and PennDOT ensures that its applicators are licensed and certified.
Stormwater runoff must be considered when planning the design of vegetation in right-of-way and public areas. "Drains that provide for water removal from roads and other inhabited areas must be kept clear of brush or other debris that would inhibit flow away from sources en route to an outlet," notes Horton.
Grasses help both above and below ground. "The upper growth of the plant helps to reduce the velocity of the water droplets hitting the soil. It reduces the impact of hitting bare soil. The root system helps to hold the soil together," explains Whaley. "The denser the planting area, the more leaf surface, the more rugged texture would all reduce the potential to reduce erosion through a rain event. You need to protect your soil while your vegetation is germinating and growing. Use vegetation control mats that can hold vegetation in place until germination. It may take anywhere from one to three weeks for grass to germinate and grow here in Pennsylvania. Then it takes time for root system growth."
Managing Vegetation Near Water
Melanie Wertz, watershed outreach manager for the Pennsylvania Department of Environmental Protection, works with property owners. She is often involved with right-of-way areas next to water sources such as streams.
"We have a program called the Stream Relief Program. In the past we have provided funding and have worked on ordinances as well as training and education to promote forested plantings next to those waterways," she says. "That would consist of trees and shrubs that are native plants. We do it because the roots help stabilize the streambanks and reduce erosion. We try to promote native plants. Here in Pennsylvania, we would encourage willow, maple, and oak trees. Those trees tend to be deeper-rooted than evergreen trees. Also, those trees and shrubs and streams provide a great habitat for songbirds and wildlife."
 Photo: BASF |
| The fescue closer to the road is treated with herbicide and mowed. |
Vegetation next to a stream also provides important habitats for necessities, such as insects, for fish, explains Wertz, which can begin a larger food chain.
"If you go into a streambank area and you do a massive planting project, oftentimes disturbed soil becomes a prime location for invasive plants," she says, noting that Japanese knotweed and mile-a-minute weed are two invasive species she's seen in the field this year.
In the western United States, where water can be in short supply, Habitat, which can be applied early in the growing season, can be used to control many water stealers such as salt cedar, according to Horton.
There are many chemicals that cannot be used close to water, and these are often determined by a state's department of agriculture. The California Department of Transportation uses Reward, a contact herbicide, to attack invasive species near streams, according to Greg Reynolds of Syngenta, maker of the herbicide. It is also used as an edging material within golf courses, he says, noting that results are visible within days. Low-ground-pressure machines, like the Geo-Boy line of tractors produced by Jarraff Industries in St. Peter, MN, can be used to clear unwanted brush in swampy areas.
Wertz notes that Rodeo, from Dow AgroSciences, is another herbicide that can be used aquatically. "It will kill vegetative plants. When you use chemicals you have to know what you're using. Some chemicals will kill all vegetation. You just have to be careful what your target is," she notes. "Navigate is safe for water. That would kill [aquatic] plant life. What we have found to be very effective is to use volunteers to do the planting and to do the follow-up maintenance."
The Susquehanna River, which winds through Pennsylvania, terminates at the Chesapeake Bay. Many organizations are actively working to keep the bay clean. Trout Unlimited is an example of one group that has helped by adopting a once-state-run buffer project that relates to the area they want to protect.
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"We have over 6,000 miles of forest buffers. We don't maintain them. In some places the landowners are responsible for maintaining them; [with] others, groups are responsible for maintaining them," says Wertz, discussing relevant plantings and site preparation. "You could be looking at $1,000 to $1,200 an acre on average."
One could argue it's difficult to win in a survival struggle of the fittest when invasive species encroach on native plants. But vegetation management product manufacturers, contractors, and state officials will continue to follow EPA mandates and make the nation's right-of-way areas a little more green.
March-April 2005
Secrets of Strength and Beauty
Right-of-way and public vegetation management strategies.
Beaten down by unexpected traffic and enduring unforgiving exposure to the elements, vegetation in public and right-of-way areas must be strong and durable and, at the same time, aesthetically appealing. To successfully manage these landscapes is to work both with and, at times of weed and seeding control, against nature. Choices made by individuals in each state affect millions of residents, and these decisions must be made with caution.Wisconsin: Working With the Prairie's Natural Support System
Right-of-way areas provide harsh living conditions for most vegetation. Vegetation along roadsides, for example, needs to be able to handle unexpected traffic and dramatic sloping along highways in some areas. Wisconsin's Department of Transportation (WisDOT) has found that the best way to tackle these challenges when choosing vegetation in these areas is to go native.
"We use native species of trees and shrubs as much as possible. Most of our standard grass seed mixes have consisted of the typical Eurasian sod-forming species such as bluegrass and fescues, along with some others," says Dick Stark, landscape architect for the WisDOT Bureau of Highway Operations. "Recently, we have been moving toward using more native grasses, with wildflowers in appropriate places where they would provide a show of color. Whatever we use needs to be able to thrive with little or no maintenance."
Because the state can become snow-covered for months during the harsh northern winter, "Salt tolerance is also an issue along the shoulders," Stark explains.
The department manages approximately 150,000 acres of roadside vegetation along about 12,000 miles of state and federal highway. "WisDOT is responsible only for state and federal highways," notes Stark. "We have no jurisdiction over county or town roads."
When landscape suffers along a system this long, maintaining it properly can be costly. "In calendar year 2003, we spent almost $5 million on mowing, almost $4.6 million on controlling woody vegetation, and just over $1 million on controlling the noxious weeds that we are required by state statute to control," says Stark. "There are three species listed in the statutes: Canada thistle, leafy spurge, and field bindweed. Our efforts are directed toward the thistle and spurge; bindweed hasn't really been a problem on our rights of way."
The best way to save money when it comes to vegetation management in public and right-of-way areas, recommends Stark, is to complete the job correctly the first time. "This requires attention to details such as preparing an adequate seedbed, using the proper equipment, seeding at the appropriate time, and so on." Using native plants can help in this respect, as well. Self-regeneration among the pre-existing species not only helps with costs but also can have a two-fold affect on improving the area's ecology.
"We have had a limited mowing policy in place since the early 1960s, which has allowed native trees, shrubs, grasses, and wildflowers to regenerate themselves on our rights of way. This also provides habitat for wildlife," says Stark. "Vegetation is also the most effective erosion control method there is."
A natural look is key to the state's public landscape. In fact, Stark says that vegetation in roadside areas is largely left "unmanaged," with some exceptions: In addition to controlling noxious weeds, WisDOT mows the shoulder of the road and, "for vision where necessary," controls woody plants that could grow to more than 4 inches in diameter in this clear zone.
"We use Transline for thistle control and Plateau for leafy spurge control," Stark says, referring to herbicides. "We also use Roundup or Roundup equivalents and Garlon products." Habitat, another herbicide that attacks invasive species, was used on a state highway project this summer.
Because of this policy of limited mowing, Stark notes, wildflowers have increased in number along Wisconsin roadsides. "We get many compliments on our wildflower ‘plantings' in areas where we have never done any wildflower plantings."
Proliferation of a different type of vegetation has caused some concern, however. "We seeded many, many acres of crown vetch for erosion control, particularly on slopes, from the late 1960s into the early 1990s," says Stark. "It grew so well that it has become invasive, moving across the fence into natural areas to the extent that we are now getting requests from our Department of Natural Resources to remove it in some areas."
With the help of a handful of hired contractors, the state is working on a project to improve the natural landscape in public areas by selectively destroying the species that threaten it. "While doing a vegetation inventory several years ago, we identified several high-quality native prairie remnants," says Stark. "Over the past three to four years, we have hired contractors to intensively manage some of them, to restore them as much as possible to their original state by removing invasive weeds and woody vegetation. We hope to continue this work in the future, although the work will be on a three- to five-year cycle, much less intense than the recent contracted work."
This prairie restoration project has been successful in part because of the use of prescribed fire.
"We have also burned a few other areas using WisDOT staff and county highway maintenance crews, sometimes aided by Department of Natural Resources fire crews," says Stark. "We feel that it is an excellent tool that must be used cautiously and judiciously."
Improving Ecology in Oklahoma
While vegetation management in public and right-of-way areas is funded by the state, in Oklahoma, communication with area residents and smaller municipalities is an important part of the Oklahoma Department of Transportation's (ODOT's) mission.
Photo: NTech Industries |
Agreements are worked out within cities to determine which public landscapes the smaller authority will care for and which the state will manage, explains Michele Dolan, stormwater coordinator for ODOT in Oklahoma City. Ongoing communication with treatment area residents also helps the department avoid conflicts. "If the landowner asks us not to spray, then we won't spray on their property," says Dolan.
Herbicide treatments, primarily Roundup used in various combinations, are typically applied to state-managed public and right-of-way areas twice annually. Herbicide regulations differ from state to state. As prescribed fire is not used as a vegetation management method in Oklahoma, herbicide use is combined with mowing, which varies depending on the climate. In non-urban areas, says Dolan, the state typically mows three times each year.
ODOT has purchased NTech Industries' WeedSeeker automatic spray system, which can help manage weeds by singling them out to eliminate them, using less herbicide and saving additional time. "[It] recognizes chlorophyll," explains Kathie Checkal of NTech Industries, based in Ukiah, CA. "When it sees the green in a weed it just sprays on that weed only. It cuts herbicide use way down, 50% to 90%."
ODOT manages 31,057 miles of roadway and maintains approximately 111,000 acres of right-of-way areas. Slope and soil types are the primary considerations when purchasing vegetation for harsh conditions in some public and right-of-way areas. An active roadside wildflower program using donated seeds is part of the state's beautification program and helps keeps costs down.
"Most of the soil in Oklahoma is really clay or really sandy," says Dolan. "We grow a lot of weeping love grass and buffalo grass and blue stem grass."
Bermuda grass is a popular choice for roadside shoulders throughout the state, particularly for its ability to handle stormwater runoff well. "The roots help hold the depth of the soil there, but the upper part of the plant stops the impact of the raindrop," explains Dolan. "[The plant selected] has to be something you can maintain without killing, and it has to be something that will handle flow. It has to have a real tight root system. Bermuda's great."
Improving the ecology of the region is a goal ODOT strives to meet because, according to Dolan, vegetation management can reduce erosion, provide habitat, produce oxygen, and please residents aesthetically.
Beauty and Power: Maintaining Rail and Utility Line Landscapes
Since ancient times, getting beauty and power to peacefully co-exist has been challenging. Railways, symbols of industry, offer landscaping design challenges to those responsible for their maintenance.
Photo: Pennsylvania DOT |
"In the railroad market, there are specialized equipment needs beyond those necessary for roadside applications," says Bill Nichols, territory manager for the State of Michigan for Townsend Chemical. He explains that these needs include trucks equipped with high rail units that allow workers to remain atop the rail as nozzles attached to the truck spray herbicides to either side of the tracks.
Todd Horton of BASF Vegetation Management Group contrasts the needs of maintaining vegetation near roadsides and near rail lines: "In the South, they actually want desired turf. In South Carolina, they use Bermuda grass," he says, explaining that herbicide applications can be used to maintain vegetative height. "They want clear sight lines around corners. They go for low-growing turf and try to manage with that in mind. This is in contrast to something like a railroad and utility [areas] where they have to have total vegetative control. Vegetation can destroy the integrity of the rail line."
Another type of roadside vegetation manager, he says, "wants to control everything but a particular plant. The same herbicide can be used for releasing a desired turf. It all has to do with the amount of herbicide put out. You may put out 3 or 4 ounces of an herbicide to release a species. Twelve ounces may control a species."
Vegetation management at rail lines, as with most public sites, depends on the slope involved. "For relatively flat areas and moderate slopes, hydraulic mulches with native mixes or grass can be used," says Sam Morris of Phoenix Paper Products, based in Lostant, IL. "For more severe slopes or moderate slopes with high water-flow potential, bonded fiber matrix [BFM] products or erosion control blankets can be used. BFM products are also used when there is a lengthy time between seeding and germination, as in some of the arid regions in the western part of the US."
The business of stabilizing slopes begins at the root of plants chosen for the job. "Any vegetation will help to stabilize slopes, but vegetation with deep, fibrous roots will do it best," says Stark. "Not only do these roots provide slope stability; they also aid in water infiltration."
Performance concerns often exceed aesthetics when in comes to caring for areas housing utility lines. "Appearance plays a small factor in most jobs," says Morris. "The most critical criterion is performance based upon the objectives of the particular site. From a practical standpoint, you do not want any unnecessary foot traffic on any revegetation project until the vegetation is well established."
Woody vegetation control is a primary consideration with utility lines. "They [vegetation management workers] want to control just the wooden vegetation," notes Horton. "They can also use selective application techniques."
During his decade in the industry, Horton has seen what he terms a dramatic shift toward looking out for what's best for the environment. Manufacturers of vegetation management products are required to produce more studies than when he began his work.
"We've seen a trend over time: Mechanical methods of vegetation management, over time, are more expensive than herbicides," he says, providing an example of a utility that mows down brush; seven years later, there might be nine stems where there once was only one. "The costs add up. With herbicides you can actually go out there and change the [environment] you're working with.
"There's a big buzzword in the industry: ‘integrated' vegetation management," he continues. "Basically, what that is is looking at a given site, using a combination of mechanical and herbicide methods, and using biological control methods such as insecticides. It's using all those tools to accomplish that objective that you want."
Electric utilities must eliminate plants that could cause outages, he explains, while at the same time they want non-threatening vegetation to thrive to protect the slopes where lines are set up. This is part of many states' battle against erosion in what can be remote right-of-way areas.
Groundcover in Pennsylvania
Being the Keystone State can be difficult when it comes to looking good. Pennsylvania's highways connect northbound travelers from the south and the west with New England. That means there is heavy traffic on both sides of approximately 40,000 miles of highway. Roadside vegetation must be selected to perform.
Photo: Pennsylvania Department of Environmental Protection |
John Whaley, landscape design supervisor for the Pennsylvania Department of Transportation (PennDOT) based in Harrisburg, says that while the slope, soil, and amount of light available ultimately determines the plants that are chosen, PennDOT frequently uses a Kentucky 31 tall fescue, which he describes as a tough grass that can handle some vehicle traffic without causing erosion.
"It can be maintained by growing to various heights," he says of the fescue. "Pennsylvania has used crown vetch, a leguminous-type plant that will grow in a wide variety of soils. It's been very adaptive to cover a wide range of subsoils that are often encountered in roadside areas. It also replenishes the soil with nitrogen."
Crown vetch provides good groundcover, explains Whaley, while not permitting larger tree growth close to the roadside. "What we have noticed over a few years is that the crown vetch eventually is going to thin out and other things come. We're to get 15 to 30 years in some areas where that crown vetch will remain a good groundcover for us."
Saving money is an issue that can arise for even the most well-funded state transportation departments. In fiscal year 2003–2004, PennDOT had a budget of $30.9 million, with about $7 million designated for mowing, $5.7 million designated for varieties of herbicide control, and $18 million allotted for tree and brush removal. Whaley says the department is working to reduce costs by trying to mow less and add long-term vegetation, including native grasses, wildflowers, and crown vetch. To save money, he says, vegetation managers must be aware of the maintenance involved in the materials they choose.
Herbicides need to be used at an early stage to keep tall vegetation from moving toward the roadside, explains Whaley.
"If you want to keep it a grass, you want to consider the mowing costs and also keep it in condition"—in other words, you don't want to allow "invasion by broadleaf weeds or volunteer woody plants," he says. "The more you mow, the less you have of that type of problem. Are you going to mow once a year or twice a year?"
While trees and shrubs are also used in public and right-of-way areas, most research with herbicides comes about because of the large amount of maintenance involved with managing grasses. PennDOT has been working with Pennsylvania State University researchers to determine how best to manage roadside vegetation. The researchers study many aspects of the work, including the length of time between mowing for the best results, as well as the effects of herbicides.
"We feel it's been well worth the money for them to make recommendations on different roadside vegetation management practices. It's a slow process, but we feel like we are making headway [and finding] an integrated approach to the problem," says Whaley. "The Penn State researchers have been looking at a number of types of mechanical equipment to apply less herbicide safely. That may take several years of looking at how the equipment is evolving and how much it costs. We're still finding the mechanical approach to cutting and putting on herbicides is slow and may not give us the control that we would like. We still feel spray equipment with various nozzles that they can use to control the spray pattern and amount of chemical applied is the least costly and most effective. The most expensive is the backpack [application]. That's very costly and time-consuming in man-hours."
All roadside herbicides have to be registered for roadside use, notes Whaley, and PennDOT ensures that its applicators are licensed and certified.
Stormwater runoff must be considered when planning the design of vegetation in right-of-way and public areas. "Drains that provide for water removal from roads and other inhabited areas must be kept clear of brush or other debris that would inhibit flow away from sources en route to an outlet," notes Horton.
Grasses help both above and below ground. "The upper growth of the plant helps to reduce the velocity of the water droplets hitting the soil. It reduces the impact of hitting bare soil. The root system helps to hold the soil together," explains Whaley. "The denser the planting area, the more leaf surface, the more rugged texture would all reduce the potential to reduce erosion through a rain event. You need to protect your soil while your vegetation is germinating and growing. Use vegetation control mats that can hold vegetation in place until germination. It may take anywhere from one to three weeks for grass to germinate and grow here in Pennsylvania. Then it takes time for root system growth."
Managing Vegetation Near Water
Melanie Wertz, watershed outreach manager for the Pennsylvania Department of Environmental Protection, works with property owners. She is often involved with right-of-way areas next to water sources such as streams.
"We have a program called the Stream Relief Program. In the past we have provided funding and have worked on ordinances as well as training and education to promote forested plantings next to those waterways," she says. "That would consist of trees and shrubs that are native plants. We do it because the roots help stabilize the streambanks and reduce erosion. We try to promote native plants. Here in Pennsylvania, we would encourage willow, maple, and oak trees. Those trees tend to be deeper-rooted than evergreen trees. Also, those trees and shrubs and streams provide a great habitat for songbirds and wildlife."
Photo: BASF |
| The fescue closer to the road is treated with herbicide and mowed. |
Vegetation next to a stream also provides important habitats for necessities, such as insects, for fish, explains Wertz, which can begin a larger food chain.
"If you go into a streambank area and you do a massive planting project, oftentimes disturbed soil becomes a prime location for invasive plants," she says, noting that Japanese knotweed and mile-a-minute weed are two invasive species she's seen in the field this year.
In the western United States, where water can be in short supply, Habitat, which can be applied early in the growing season, can be used to control many water stealers such as salt cedar, according to Horton.
There are many chemicals that cannot be used close to water, and these are often determined by a state's department of agriculture. The California Department of Transportation uses Reward, a contact herbicide, to attack invasive species near streams, according to Greg Reynolds of Syngenta, maker of the herbicide. It is also used as an edging material within golf courses, he says, noting that results are visible within days. Low-ground-pressure machines, like the Geo-Boy line of tractors produced by Jarraff Industries in St. Peter, MN, can be used to clear unwanted brush in swampy areas.
Wertz notes that Rodeo, from Dow AgroSciences, is another herbicide that can be used aquatically. "It will kill vegetative plants. When you use chemicals you have to know what you're using. Some chemicals will kill all vegetation. You just have to be careful what your target is," she notes. "Navigate is safe for water. That would kill [aquatic] plant life. What we have found to be very effective is to use volunteers to do the planting and to do the follow-up maintenance."
The Susquehanna River, which winds through Pennsylvania, terminates at the Chesapeake Bay. Many organizations are actively working to keep the bay clean. Trout Unlimited is an example of one group that has helped by adopting a once-state-run buffer project that relates to the area they want to protect.
"We have over 6,000 miles of forest buffers. We don't maintain them. In some places the landowners are responsible for maintaining them; [with] others, groups are responsible for maintaining them," says Wertz, discussing relevant plantings and site preparation. "You could be looking at $1,000 to $1,200 an acre on average."
One could argue it's difficult to win in a survival struggle of the fittest when invasive species encroach on native plants. But vegetation management product manufacturers, contractors, and state officials will continue to follow EPA mandates and make the nation's right-of-way areas a little more green.