Threats to the Parks

Do you know your invasives? Click here to take our Invasives Species Quiz!

Pests and Pathogens:

• Asian Longhorned Beetle (ALB)
• Boston ALB Eradication Update
• Hemlock Wooly Adelgid

Invasive Species:

• Phragmites
• Bittersweet
• Buckthorn
• Garlic Mustard
• Japanese Knotweed
• Multiflora Rose
• Black Swallow-wort
• How You Can Help

Other Threats:

• Climate Change
• Geese
• Litter
• Pollution

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Pests and Pathogens:

Asian Longhorned Beetle (ALB)

The Asian Longhorn Beetle is a serious threat to deciduous hardwood trees including maples, birches, horsechestnuts, sycamores, poplars, willows and elm, species that characterize the temperate urban forest in the northeast. Many of the trees in the parks of the Emerald Necklace are susceptible to this exotic beetle, which causes damage by tunneling into the trunks and branches of trees, weakening and eventually killing them. An infestation first discovered in August of 2008 in Worcester, Massachusetts affected a total of 94 square miles and led to the necessary destruction of hundreds of mature host trees- a devastating loss for the urban landscape.

More recently, in July of 2010, 6 maples in Jamaica Plain were found to have Asian Longhorned Beetles. The infected trees were immediately chipped and since then the Emerald Necklace Conservancy and other groups have held ALB trainings and walks in the area. Luckily, Conservancy volunteer groups and the USDA’s own survey crews have not found any additional infestations.

Adult beetles are 0.75’’ to 1’’ long, have a shiny black body with irregular white spots and long antennae 1 to 2 times its body length. The larvae is 2’’ long with off-white bodies and brown mouthparts. By identifying and monitoring Asian Longhorn Beetle infestation, citizens can potentially deter and prevent future threats to the Emerald Necklace parks system.

Monitor park trees for the following four signs of Asian Longhorn Beetle activity: 1) Exit holes, dime-sized; appear high in tree branches in July and August, when new adults emerge from their host trees. 2) Sawdust appears on ground or branches where adults have exited. 3) Oozing sap may appear in places where the beetle has damaged a tree. 4) Oval grooves in the bark made by females laying their eggs.

To report possible Asian Longhorn Beetle sightings, do one of the following:

• Visit the Massachusetts Natural Resources Collaborations website
• Call the Massachusetts ALB Cooperative Program at 1-866-702-9938
• Call the Massachusetts Department of Agricultural Resources Pest Hotline at 617-626-1779

For more information, please consult the Massachusetts Introduced Pests Outreach Project website

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Boston ALB Cooperative Eradication Program Update

May 26th, 2011

Key Message: Residents of the ALB regulated area established within Suffolk and Norfolk counties are asked to refrain from moving firewood and wood debris outside the regulated area. Report suspect Asian Longhorned Beetles to 1-866-702-9938.

• Number of ALB infested trees confirmed in the Boston project area: 6 (0 in 2011)
  
• Number of ALB infested trees removed: 6
  
• Total number of trees surveyed in the Boston program area to date: 51,184
  

Background: On July 3, 2010 USDA/APHIS agriculture officials confirmed the presence of Asian Longhorned Beetle on the grounds of Faulkner Hospital. Five infested red maple trees were identified initially and one additional infested red maple was identified on July 5, 2010. The six infested trees were removed on July 6, 2010. On July 6, a press conference was held at Faulkner Hospital announcing the find. The Commonwealth of Massachusetts and USDA/APHIS have established a regulated area covering portions of Suffolk and Norfolk counties.

Resources: Click on the following links for more information

• ALB informational and reporting website
  
• ALB Information from the MA Department of Conservation and Recreation
  
• ALB Map of the regulated portions of Suffolk and Norfolk counties
  
• ALB Information from the MA Department of Agricultural Resources
  
• ALB Information from USDA’s Animal and Plant Health Inspection Service
  
• ALB Information from U.S. Forest Service
  

Media contacts:
Boston ALB Media Office: 617-894-8014
MA ALB Media Office: 508-852-8044

Compiled by ALB Program Cooperators.

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Hemlock Wooly Adelgid

Hemlock Wooly Adelgid (HWA) is an insect that feeds on the sap of hemlock trees. It has become a major threat to the Eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana), coniferous species found in the eastern US. In central New England, Eastern hemlock trees are a vital component of native forests and are a major fixture in the boreal forests of northern Maine, Vermont and New Hampshire. Often found near stream banks, hemlock trees protect against erosion and provide habitat for wildlife. It is estimated that 50% of the Eastern hemlock population has been impacted by HWA, from Georgia to Massachusetts. If average temperatures continue to rise annually, HWA will have a devastating effect on the northern hemlock population.


A hemlock tree that is infected with HWA will have small, white egg sacks clinging to the underside of its branches. These egg sacs resemble tufts of cotton. As the HWA feeds on the sap of hemlock shoots, it also injects a toxin that weakens the tree, which loses needles and fails to produce new growth as a result. While healthy hemlocks are a verdant dark green, a hemlock that is infected will be a grayish-green. In New England trees infected with HWA die four to ten years after infestation. If a tree is able to survive the direct effects of infestation, it is typically so weak that it dies soon after from other causes.


Solutions to HWA are limited. The adelgid can be physically removed from the tree by washing or cutting off infected branches. The use of chemical pesticides is an option, but often passed over due to the potential contamination of waterways and aquatic environments. Because the HWA is often found in forest settings, the large-scale use of pesticides would alter and damage delicate ecosystems. Observing and reporting HWA is the first step towards controlling this destructive pest and saving our native hemlock trees.

Resources:

• Hemlock Hill Management and Research at Arnold Arboretum
  
• More information available here, provided by the USDA.

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Invasive Species:

Identification and control of invasive plant species in the Emerald Necklace is a key step towards preserving our historic park system. After they are introduced, non-native plant species are able to grow and reproduce rapidly because they do not face the competitors and predators that are present in their natural habitat. Without a natural check on their growth these plants can quickly become invasive, outcompeting native plants and spreading rapidly, resulting in expansive monocultures that damage existing plant communities and the wildlife that depends on native habitat. This reduction in biodiversity also results in increases susceptibility to pests and pathogens. Invasive plant species pose a significant threat to natural resources and can negatively impact the health of the Emerald Necklace parks, especially the park’s woodlands, wetlands and river edges.

Removing or managing invasive species preserves and maintains the parks system as a healthy place for plants, people and wildlife. Listed below are descriptions of some of the most abundant invasive plants found in the Emerald Necklace parks system, the specific threats that they pose, and solutions for their control.

Phragmites

Common Reed, Phragmites australis Description: A grass that can grow over 15 feet in height with feathery seed heads. Has elongated leaves 1.5 inches at their widest point. In late July and August the flowers appear bushy and fluffy due to hairs growing from the seeds.


Threat: This introduced type
of reed forms large dense monocultures that can quickly take over a marsh community blocking river flow and
upsetting marsh hydrology. When dry, Phragmites can pose a fire hazard. Easily transported, it can spread rapidly. Click here for more information on the impact that phragmites is having on the Emerald Necklace parks.


Control: The best method for controlling large established stands of phragmites is herbicide. However scheduled mowing and controlled burning are other options.

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Bittersweet

Asian Bittersweet, Celastrus orbiculatus
Description: A woody perennial plant that grows as a climbing vine. Its leaves are round, alternate, and glossy with finely toothed margins. The male and female plants differ in the fact that only the females bear fruit. The females produce small round yellow capsules that break open to expose three orange center, each containing one or two seeds.

Threat: A woody vine which grows rapidly, shading and strangling native plants. See picture on the right, Bittersweet ascending a tree.

Control: A variety of control options can be used to remove Bittersweet. When vines are climbing trees a combination of cutting followed by the application of herbicide is the most effective approach.

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Buckthorn

Glossy Buckthorn, Frangula alnus Description: Small tree with dark glossy green leaves, “warty” dull gray-brown bark. Leaves are broadly oval, rounded or pointed at the tip, with 3-4 pairs of upcurved veins, and have jagged, toothed margins.

Threat/Impact: Forms a dense understory and interferes with succession and regeneration of native species.

Control: Uprooting seedlings by hand and larger trees using a weed wrench is effective, however soil disturbance can release seeds stored there. See picture below, Volunteers pulling buckthorn in Olmsted Park.

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Garlic Mustard

Garlic Mustard, Alliaria petiolata
Description: An herb with stalked, triangular to heart-shaped, coarsely toothed leaves that give off an odor of garlic when crushed. First year plants (see picture below) appear as a small clump of leaves close to the ground. Mature flowering plants (see pictures above) can reach 3 ½ feet with clusters of small white flowers, each with four petals in the shape of a cross. Threat: By displacing native plants, garlic mustard threatens butterfly species which depend on natives for reproduction and feeding.

Control: Pulling the plant out steadily, taking care to release the entire root from the ground. Removal is needed annually to exhaust the seed bank.

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Japanese Knotweed

Japanese Knotweed, Polygonum cuspidatum Description: Japanese knotweed is an upright perennial herb with broad oval leaves, 6 inches long by 3-4 inches wide, and white to greenish-white flowers. Stems are smooth and bulge at the point where leaves meet the stem. See picture below, Knotweed in its early growing stages. Threat: It forms thickets and invades riparian areas, threatening native plants (see picture below). Control: Pulling the plants is ineffective, and actually causes increased vigor. Cutting the flowers off the plants before they set seed can slow the spread of the plants. To eradicate a colony injecting herbicide has been found to be the only effective solution.

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Multiflora Rose

Multiflora Rose, Rosa multiflora Description: Thorny perennial shrub with clusters of tiny white-to-pink roses. The arching stems have leaves which are divided into 5 to 11 sharply toothed leaflets. Bright red fruit will develop in the summer (see picture below). Threat: Multiflora Rose outcompetes other plants and forms a dense, impenetrable thicket (see picture below). Control: Mowing can keep bigger populations under control, but the most effective means of control is careful application of herbicides.

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Black Swallow-wort

Black Swallow-wort, Cynanchum louiseae

Description: Black Swallow-wort grows up to 2 m (6.5 ft.) in length. Leaves -- 2 to 5 inches long -- are opposite, toothless, oval-shaped with pointed tips, and dark green with smooth, shiny surfaces. Clusters of 6-10 flowers are produced in opposite, axillary cymes from June to September. Flowers of black swallow-wort are dark purple and each of the five pointed petals are equilateral triangles and finely pubescent with downy white hairs. Immature pods are green, turning brown with maturity.

Threat/Impact: Its vines can grow rapidly and smother nearby native vegetation. It also has the ability to dominate the understory of a woodland. Wind-dispersed seeds allow it to disperse over long distances. When it is cut, this plant re-sprouts vigorously, making control difficult.

Control: Eradication is difficult once a colony is established because plants form a dense, knobby mass of underground roots. Initial control efforts should concentrate on plants in sunny areas since they produce the most seeds. All pods should be removed before they open, and then burned or land-filled to prevent seed release. Triclopyr or glyphosate with a surfactant can be applied to foliage during the growing season. Cut-stem treatment with glyphosate is also effective but labor intensive. If plants are hand-dug, all roots must be removed. Monitor for populations in late summer when plants turn golden yellow and pods become prominent.

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How You Can Help

Volunteer with the Emerald Necklace Conservancy and learn how to identify and manage invasive species. With your help, we can work towards the eradication of invasives and the reestablishment of native plants and habitat. Below, Volunteers uprooting garlic mustard at the 2010 Garlic Mustard Pull. Click here to access the volunteer form and add your name and contact information for future notices and updates of upcoming volunteer events. We look forward to meeting you and working together to preserve the parks as a vibrant natural resource.

Click here to see our event calendar.

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Other Threats:

Climate Change

As average annual temperatures have climbed, there have been significant changes to park ecosystems. From altered microbial communities in soils to higher water levels in park waterways, the delicate balance that exists between nature and the urban environment is increasingly weighted to the whims of rising city temperatures and extreme weather patterns.

Impacts on urban forests include altered growth patterns, tree decline or loss, and an increase in drought-tolerant species. Rapidly changing temperatures and shifts in available water can lower adaptability to site conditions, weakening trees and making them more susceptible to destructive pests and pathogens. When a large storm event brings heavy rainfall, flooding along park waterways can occur. The resulting erosion weakens riverbanks, redistributes soil and plant materials, and contributes to water quality downstream.

Though urban parks can be negatively affected by climate change, they also help mitigate extreme conditions. Trees absorb carbon dioxide and release fresh oxygen in return. They help protect our water supplies, absorb the noise of city life and can reduce energy use by blocking cold winter winds and providing shade, lowering temperatures in summer months. In order to ensure that the benefits of park systems and networks of open space continue in a changing environment, decisions about future park plantings will consider natural patterns of succession and a plant’s hardiness and ability to withstand variable conditions.

Conclusions from the ongoing discussion of climate change and its impacts direct current and future action at the Emerald Necklace Conservancy towards strategies of adaptation and resilience. Planting choices, management plans and landscape solutions work together to maintain healthy parks while recognizing that the environment will continue to change and evolve over time.

Click here to learn more about climate change in New England.

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Geese

Canadian geese are a dominant presence throughout the Emerald Necklace parks. Producing up to 1.5 pounds of droppings per goose, per day, geese ingest an huge amount of vegetation on their own, and often eat even more, as a result of being fed by humans. Geese will concentrate wherever people feed them, encouraging birds to stay in one place and causing the population of the flock to grow beyond what the surrounding habitat can support. Their growing numbers lead to a variety of problems including over-grazing of park turf, aggressive behavior by nesting birds, safety hazards near roads, nutrient loading to ponds and waterways and accumulations of droppings and feathers on high use areas including public walkways. As a result, flocks of local-nesting or “resident” geese render many areas within the Emerald Necklace parks system unusable.

Municipal actions towards dealing with the geese include population stabilization, strategic landscaping, decoys, non-toxic repellents, routine maintenance and cleaning, monitoring and education. While site aversion is important to controlling the goose population, the most effective way for park users to reduce “goose grief” in the Emerald Necklace parks is simple: do not feed the geese. Feeding urban wildlife has negative impacts on the wildlife, the environment and the community. Instead of feeding wildlife the public can work together with the Emerald Necklace Conservancy to protect natural food and water sources which can provide healthy, safe and suitable habitat for all wildlife that call the Emerald Necklace parks home.

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Litter

Discarded paper, bottles, cans and other human litter found in the Emerald Necklace parks is not only careless and unsightly- it can be dangerous and detrimental to the wildlife and plant communities that call the parks home. From plastic bags to small pieces of plastic, litter can trap or choke birds, mammals, amphibians and fish. Debris can end up in park waterways, slowing water flow and clogging storm drains resulting in flooding and habitat destruction.

Through combined volunteer efforts and advocacy we can stop the accumulation of trash in our parks and public spaces. Beverage containers, one of the most common trash items, are made from materials like PET plastic and aluminum, which cannot biodegrade. Without public and volunteer participation, these common trash items remain in parks indefinitely.

The Emerald Necklace Conservancy is an energetic and committed partner in the effort to update and expand the Massachusetts Bottle Bill, which would add a five cent redemption value to bottled water, sports drinks, teas, juices and other beverages. By adding a cash value to these containers we can prevent them from ending up in our parks and landfills. Look for an update when the bill is refilled in the next legislative session. Click here for more info on the Conservancy's advocacy efforts.

Routinely picking up and properly discarding or recycling litter is a collective effort that has a positive impact. Please volunteer with us in our continuing efforts to keep the parks of the Emerald Necklace litter-free.

Annual Earth Day Muddy River Clean-Up
On April 23 at 9am, join us for the 2011 Muddy River Clean-up in conjunction with the 11th Annual Earth Day Charles River Clean-up. The Muddy River is a tributary of the Charles River, flowing through the Back Bay Fens. We will be picking up trash and downed tree limbs along the river bank between Brookline Avenue at Landmark Center and Mother’s Rest on Boylston Street. Click here for more information. See picture to the right, Volunteers at the Muddy River Clean-up pick up litter alongside the Phragmites. More photos from the 2010 clean-up here.

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Pollution

The waterways that run through the parks of the Emerald Necklace Conservancy are susceptible to the effects of Nonpoint source pollution (NPS)- water pollution from a variety of diffuse sources and locations, often contaminated stormwater runoff from impermeable urban surfaces such as roads, highways, parking lots and conventional lawns. Collectively, this urban runoff often contains chemicals, traces of contaminants such as automotive products, fertilizers and pesticides that are often channeled through municipal storm drains and discharged into large water bodies.

Not all runoff is simply sent “away,” channelled immediately into underground drain systems. NPS polluted water can also be absorbed by permeable, vegetated surfaces or flow into our urban rivers and streams, posing a significant threat to urban parks and waterways. Sediment, a principal type of NPS pollution, is negatively impacting water quality and stream bank structure throughout the Emerald Necklace. Sediment often enters surface waters as loose soil or silt carried by runoff or resulting from bare, degraded banks. This can result in turbidity or cloudiness in water bodies, blocking essential light from reaching depths that support aquatic plant and animal species.

Erosion and sediment controls include the installation of vegetated riparian buffers or planted stream banks that are able to stabilize soils with deep root networks. Appropriate native wetland species hold soils together and can cleanse or filter polluted water before it enters our waterways. Primary goals of the ongoing Muddy River Restoration Project include improvement of water quality, enhancement of aquatic/riparian habitat, restoration of landscape and historic resources and implementation of best management practices. The Emerald Necklace Conservancy is looking at ways to help achieve these goals while addressing NPS pollution as a major concern.

More information on Nonpoint Source Pollution here.

Click here to learn about the Muddy River Restoration Project.

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