But a regional conservation group is working with local volunteers to get to the root of invasive trees, shrubs and weeds -- a spreading problem which could affect the quality of wild habitat and recreational opportunities throughout the Kiski-Conemaugh river basin.
At recent training sessions in Saltsburg and St. Michael, the Johnstown-based Natural Biodiversity Conservation Strategy program recruited 14 new volunteer "weed watchers" to help the organization identify and address the most severe intrusions by such nuisance invaders as Japanese knotweed.
Currently numbering more than 30, the weed watchers will "be our eyes throughout the river basin to identify (invasive growth) early and enable us to respond rapidly," said Kylie Daisley, projects manager for Natural Biodiversity.
Trained to recognize objectionable plant species by their leaves and blooms, the corps of watchers will venture out on three weekends throughout the summer to monitor selected sites along the river basin's major waterways.
Return trips to the same site are needed, Daisley explained, because, "Different plants sprout, bloom and complete their life cycle at different times."
Weed watcher Carol Kelly, an active member of the Herb Society of Historic Saltsburg, has agreed to keep tabs on the new Kiski section of the West Penn hiking and biking trail, bordering the Kiskiminetas River downstream from Saltsburg.
"In the river basin, knotweed is the most prevalent invasive species," Daisley said.
Typical of many other species so classified, naturalists indicate knotweed was introduced to the United States as an ornamental plant. It was brought from Eastern Asia, probably in the late 19th century.
But its unchecked ability to propagate itself allowed it to stray into natural areas, dominating and displacing the wider variety of native plants there.
"A very small fragment of the vegetation is needed to regenerate it," Daisley said. "It sends out new plants along its roots and also produces seeds by the thousands. Only 10 to 20 percent of those are viable, but that's still a lot."
With "a root system that can go three meters deep," she added, "You'll even see it growing in coal refuse piles."
"For all of the invasive plants there are better, alternative native species," Kelly said.
For those who are attracted to knotweed's one redeeming aspect -- sprays of tiny white flowers which bloom in the summer -- the National Park Service and U.S. Fish and Wildlife Service recommend planting such similar native species as sweet pepper bush or Virginia sweet spire.
Those agencies are concerned because, Daisley pointed out, "Invasive plants affect the rivers and the aquatic life in them."
She explained, competition from invasive species can choke out native trees and shrubs. Knotweed, in particular, can tower up to 10 feet, overshadowing young saplings in search of sunlight.
Said Daisley, "That decreases the tree canopy over the river, and the water temperature can rise," negatively affecting fish survival.
In addition, there will be fewer nearby trees shedding leaves and dead limbs into the water. "Leaf matter provides food for aquatic insects, and tree limbs can provide habitat for fish," she said.
Unlike native plants it has out-muscled, Daisley said, "Knotweed doesn't produce berries for birds and wildlife to feed on. You can see how one plant can disrupt a whole system."
A naturally diverse habitat features plants with roots growing at a variety of depths. "It offers a close network of roots to help stabilize the soil," she said.
On the other hand, when a "monoculture" such as knotweed gains dominion, "You have one root type at one depth," leaving the soil more prone to erosion.
Growing in dense thickets, knotweed has jointed stems that resemble bamboo and can form a nearly impenetrable barrier for anglers or kayakers who want to access rivers.
"It decreases the opportunities for recreation and economic potential in an area," Daisley said.
Natural Biodiversity is doing more than just assessing the threat posed by such weeds. It has taken steps to contain them.
The organization developed an initial demonstration project for eliminating knotweed on a different segment of the West Penn Trail, not far from Saltsburg's community playground.
Since then, it has expanded its efforts to include 19 other sites, trying various methods to control invasive plants.
"To increase awareness, all are on public lands, river access points and trails with a high visibility to the public," Daisley said.
Using controlled application of herbicide, she reported, the knotweed at Saltsburg was wiped out in a designated survey plot measuring 33 square feet.
"It had basically formed a tunnel over the trail," Daisley said of the original knotweed growth. "Now you can see the river from the trail."
Also, a variety of native species has returned in place of the knotweed.
"In three years, we went from a monoculture of one species to 18 different species," Daisley said, adding, "This year, that number has gone up into the 20s."
During a walk along the Saltsburg trail with Kelly and other weed watchers, Daisley identified jewelweed among the native plants which have re-emerged in the absence of knotweed. She wasn't surprised, noting jewelweed is considered to be a "pioneer species" in areas which have been cleared of vegetation.
Unlike knotweed, Kelly noted jewelweed is a useful plant.
She explained, "If you encounter some poison ivy, break the stem and rub it on the affected area and it will reduce the itching."
Conveniently, jewelweed is often found growing near poison ivy.
Noting her husband is allergic to poison ivy, Kelly said she sometimes makes tea, juice or ice cubes with jewelweed, all of which are applied topically.
Spraying at the Saltsburg location was limited to herbicides which the federal Environmental Protection Agency has approved for use in or near water, Daisley said. A certified consultant came in twice each year, selectively spraying the herbicide only on the targeted weeds.
Daisley explained, "In the spring, you're killing the above-ground vegetation, forcing the plant to use up its energy to sprout new growth."
When the application is repeated in the fall, she added, the herbicide kills the weed at its roots -- drawn there along with nutrients the plant is storing up for the coming winter.
Daisley said her group is hoping to hand off future spraying duties to Jack Maguire -- a Saltsburg resident and member of the Conemaugh Valley Conservancy, which maintains the trail.
Now that the efficacy of spraying has been demonstrated in Saltsburg, Daisley said the organization is experimenting with other weed control methods at some of its other project sites.
"We're hoping to decrease our use of herbicides," she said.
At some sites, Daisley explained, a volunteer group of "weed whackers" uses lopping tools to cut down the hardy knotweed plants at the end of June.
Then spraying can be limited to the fall.
Seward residents Ruth and Robert Moore were among about eight weed whackers who last summer attacked three acres of knotweed growing along the Conemaugh River in their community, near the end of Fifth Street.
Noting they are fans of kayaking, Ruth said the couple's hope is to eventually develop the knotweed-clogged site as a recreational river access point.
They confirmed that loppers worked best as they trimmed back the tough plants. Still, Ruth noted, "There's so much to cut, they get dull. You either have to sharpen them or get another blade."
"We developed a technique," Robert said. "One guy was cutting the knotweed and the other guy was behind him, piling them up."
Another alternative also is being studied.
Daisley said, "We're experimenting with disturbing the root system and breaking it up into smaller clumps."
While results at the weed whacker sites are promising, she indicated the jury is still out on the root disturbance technique.
Sites near the Bairdstown Bridge in Blairsville and the nearby Westinghouse plant are receiving two doses of herbicide each year.
Meanwhile, the weed whackers have tackled another control area along the proposed Hoodlebug Trail extension in Blairsville.
Root disturbance is being tried along the Kiski section of the West Penn Trail.
In a separate effort, Daisley said, the weed watchers are making observations on the ground, in an attempt to verify the findings of two aerial vegetation surveys completed last year.
Daisley explained the entire river basin was photographed with a "true color" process.
That allowed the staff to identify likely monoculture sites by comparing the texture and density of foliage shown.
A separate hyper spectral survey, targeted along the basin's six major rivers, examined the wavelengths of light reflected from the various plants.
Similar to a human fingerprint, Daisley said, each species of plant generates a unique set of wavelengths which can be used to identify it.
Director Kristin Sewak said Natural Biodiversity is particularly anxious to determine if there are any area patches of giant hogweed.
"It's actually a health hazard for humans," she said, explaining contact with its sap and subsequent exposure to sunlight can cause severe irritation, possibly resulting in blisters or scarring.
Also taking part in the Saltsburg weed watcher training was Timothy Murphy, a forester from Clarksburg.
"A good deal of the work I do with private landowners involved control of invasive species," he said.
Some invasive plants, such as the tree of heaven [NOTE: and black walnut], an 18th century Chinese import, have their own secret weapon.
Also known as stinking sumac, the tree produces chemicals whish kill or prevent other plants from growing in its vicinity.
But, Murphy indicated, more commonly, invasive species simply outcompete their native counterparts.
Though it is valued as a cultivated tree in lawns, the Norway maple is considered invasive when it spreads into wild areas.
Daisley explained it can be distinguished from the native sugar maple by its leaves, which are darker in color and contain a milky sap in the stem.
Kelly added, in the fall, the leaves of the Norway maple turn a rich yellow color, while those of the sugar maple turn orange.
According to Sewak, Natural Biodiversity works with an annual budget of about $300,000 and a staff of two full-time employees, three Americorps volunteers and a student intern.
The majority of the funding has been provided by annual grants of $240,000 through the United States Department of Agriculture's Animal and Plant Health Inspection Service (APHIS).
A third year of funding has been approved for the 2005-06 fiscal year.
Also contributing to the budget are donated and in-kind services.
Daisley said the organization has implemented a research project on the South Fork of the Little Conemaugh River, in an attempt to document the effects invasive plants have on water quality and wildlife habitat.
An economic impact study is next in line.
To find out more about Natural Biodiversity's programs, log on to http://www.naturalbiodiversity.org/.
Carol Kelly has invited birds, bees and butterflies to share her backyard near Saltsburg.
Now she's hoping to gain officials' recognition of her efforts through the National Wildlife Federation's Habitat Stewards program.
Instructor Kylie Daisley, who signed Kelly up for the program at a recent training session in Saltsburg, explained the program "encourages landowners to use native plants to create a wildlife habitat in their yards. It's an opportunity to be engaged in community stewardship and beautification."
Kelly, a library administrator at Saltsburg's Kiski School, has an extensive knowledge of plants through involvement in the Herb Society of Historic Saltsburg and as a Penn State master gardener and member of the Western Pennsylvania Mushroom Club.
She already has created inviting areas for other winged creatures in her yard on the Kiski School campus. Additionally, as part of the Habitat Stewards program, she's planning to install a bat box.
"Bats eat a lot of night-flying insects, including mosquitoes," she said.
She noted the box, constructed by her husband, Larry, "has a lot of narrow shelves inside," from which the bats can hang.
To have her property certified as a backyard wildlife habitat, Kelly will have to complete 24 hours of training and 50 hours of work on yard improvements
Daisley said creation of habitats, like Kelly's, on school properties is one of the goals of the program.
She pointed out, "Not every school can afford to take students to natural areas," such as the Powdermill Reserve in Rector.
Kelly noted a variety of plants are needed to provide a habitat for butterflies.
Some, like the feathery herb, fennel, are important to the early stages of a butterfly's development. "The black swallowtail butterfly will lay its eggs on fennel," she explained.
Other flowering species provide nectar for adult butterflies.
"They're little fast-food stops along the way," for migrating butterflies species, Kelly said. "The butterflies won't come, if people don't plant the plants."
For their sustenance, large butterflies, like the monarch, need large, showy blooms such as are produced by the cosmos and zinnia.
"These are platform flowers that provide them something to land on," Kelly explained.
But, she noted, monarchs are in trouble when it comes to reproducing.
She explained the species is particular about laying its eggs on the milkweed plant.
But, "With all the roadside spraying, the milkweed population is declining rapidly. It's getting harder and harder for the monarchs to find host plants."
The tubular blooms of foxglove are among the nectar-producing flowers Kelly cultivates as an appetizer for hummingbirds.
Bee balm, a native species which is Indiana County's official wildflower, is a favorite of butterflies and hummingbirds alike.
Echinacea, also known as purple cone flower, is another native species which has multiple roles in the garden, Kelly noted:
"The Native Americans used it as an immune-boosting herb," a fact that the rest of the world has since discovered. Also, "It's a great platform for attracting butterflies.'
Though small native American bees don't produce honey, they still are important for pollinating plants.
To attract them, Kelly makes use of a plant species which has become a widespread nuisance: Japanese knotweed.
She bundles together foot-length sections of the plant's hollow, bamboo-like stems, which are just the right size for the bees to lay their eggs in, and hangs them outside her garden shed.
After the bees deposit their eggs, "Then they capture a small caterpillar or some other prey and place it inside for the young bees to eat as they grow," she said. Finally, "They plug the end with some mud."
In line with backyard habitat guidelines, Kelly has turned a water-logged portion of her lawn into a "bog garden."
"Rather than put in some drain tile," she found, "It's easier to work with nature."
Describing her varied bog plantings, Kelly noted, "A persimmon tree doesn't mind wet feet," while, "Mint is great in any moist area."
As an added benefit, the bog attracts toads, frogs and dragonflies, all of which augment pest control by eating mosquitoes.
But, Kelly cautioned, if a homeowner plans to install a bog garden, it's still important to treat the area to prevent it from harboring the larvae of mosquitoes, which are a chief carrier of such diseases as West Nile virus.
She uses a bacterial agent, marketed as a "mosquito dunk," which attacks only the mosquito larvae and is not harmful to other animals or people.
"The more different types of ecosystems you have in your habitat, the better," Kelly concluded.
"The more varied the habitat, the more varied species you're going to attract."
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