BBC Report to CPC_2019-02-08_Contract 331-16_FINALFINAL REPORT TO THE COMMUNITY PRESERVATION COMMITTEE
FROM THE BROAD BROOK COALITION (CONTRACT 331-16)
FEBRUARY 2019
Goals: From 2016 through 2018, Broad Brook Coalition continued its efforts to control or
eradicate several species of invasive plants in the Fitzgerald Lake Conservation Area (FLCA)
with funding provided under contract 331-16 from the Community Preservation Committee. The
primary target species were glossy buckthorn (Rhamnus frangula) in Cooke's Pasture and its
periphery, black swallow-wort (Cynanchum louiseae) in Cooke's Pasture, and spotted and
brown knapweeds (Centaurea maculosa and Centaurea jacea) in Cooke's Pasture and on the
Fitzgerald Lake dam. Small amounts of several other invasive plant species were also targeted.
General Approach: Owing to work performed over the past several years, we no longer have
the dense concentrations of invasive plants in Cooke's Pasture and adjoining areas that we
noted ten years ago and estimate that the populations of the targeted plants has been reduced
by around 95% compared to their prevalence in 2008--2009. Rather, they are now dispersed,
requiring the selective targeting of individual invasive plants in a background of native plants.
Land Stewardship, Inc. (LSI, formerly Polatin Ecological Services, LLC), which has carried this
work, has proven to be very adept at limiting herbicide treatment to target plants without causing
collateral damage to surrounding grasses, flowers and native shrubs.
Buckthorn in Cooke's Pasture and Its Forested Perimeter. Cooke's Pasture consists of
approximatey seven acres and is maintained as open shrubland by periodic mowing. Roughly
five years ago, it became evident that mature glossy buckthorn trees growing in the ~9-acre
forested buffer zone between Cooke's Pasture and the Broad Brook marsh provide an abundant
source of seeds that can spread and give rise to new buckthorn growth in the pasture. Some of
these trees were treated with herbicide in 2011 and 2013, but coverage was not complete and a
number of small as well as large buckthorns persisted in the periphery. In March 2016,
buckthorns in the buffer zone were systematically cut in preparation for subsequent herbicide
treatment. This work was carried out under CPA contract 250-13.
Each summer of the present contract period, LSI crews treated buckthorns in Cooke's Pasture
and its forested buffer zone with a combination of the herbicides Garlon 3A, Escort XP and
Milestone using a targeted, low-volume foliar spray. Initial treatment was carried out in August
and the LSI crew returned several weeks later to treat any plants missed in the earlier herbicide
application. Visual inspection in the fall revealed that most of the buckthorns had been
effectively suppressed. While we have observed the appearance of new buckthorn growth in the
treated areas each spring, the plants were fewer and smaller, indicating that they had grown
from seed. This suggested that the underground root systems, which had earlier been
responsible for much of the re-sprouting, had largely been abolished. Over the same period,
buckthorns in the shrub islands were treated with Rodeo (glyphosate) by the cut-stem method.
Knapweeds in Cooke's Pasture and on the Fitzgerald Lake Dam. Concurrent with buckthorn
treatment, the LSI crews also targeted spotted and brown knapweeds in Cooke's Pasture and
on the dam, as well as small amounts of other invasive plants, including autumn olive,
bittersweet and exotic honeysuckle. If left unchecked, knapweeds can overtake grassy fields
and maintain their predominance through the release of products that adversely affect the
growth of native plants. Here again, the plants were treated with a low-volume pray of Garlon 3A
or Milestone. By fall 2017, the knapweeds seemed to under good control, but in the summer of
2018, we noticed a resurgence of these plants for unknown reasons although the warm, wet
weather may have played a role. Close monitoring and spot herbicide treatment will be required
in the future to keep these plants under satisfactory control.
Black Swallowwort in Cooke's Pasture. Black Swallowwort is an invasive vine that can
compete with native vegetation, replacing grasses, goldenrod and milkweed by monotypic mats
and negatively impacting insects and animals such as turtles and birds that depend upon a
healthy grassland or shrubland habitat. A small patch of black swallowwort was discovered in
the central lobe of Cooke's Pasture in 2012. Sporadic herbicide treatment failed to prevent this
plant from going to seed and the infestation expanded to roughly one-quarter of an acre. A
systematic effort to eradicate black swallowwort, initiated in 2016, has reduced the size of the
infestation to about one-tenth of an acre by spraying individual plants with either of the
herbicides Garlon 3A or Vastlan (a triclopyr derivative) in June each year. Eradication of this
invasive is possible, though several more years of selective herbicide treatment will be
necessary owing to the persistence of its seeds in the soil.
Other Efforts to Control Invasive Plants in the FLCA. In each of the past three years,
volunteer crews removed garlic mustard and multiflora rose by hand at the North Farms Road
entrance to the FLCA and pulled large amounts of water chestnut from Fitzgerald Lake. At the
same time, follow-up herbicide treatment of Japanese knotweed on Marian Street and
Phargmites in the Broad Brook Marsh were carried out by O'Gara Landcare with funding from
the BBC.
February 8, 2019
Robert A. Zimmermann
President
Broad Brook Coalition
BUDGET SUMMARY
Expenditures in 2016:
Budgeted Expended
Landscape Stewardship, Inc.
Buckthorn control in buffer zone, $ 2,500 $ 2,500
black swallowwort in pasture
Buckthorn, knapweed control in pasture 1,500 1,500
Buckthorn, knapweed and swallow- 600 600
wort control in pasture: follow-up
Buckthorn control in buffer zone 1,500 0
Subtotal: 4,600
Expenditures in 2017:
Landscape Stewardship, Inc.
Black swallowwort control in pasture 250 250
Buckthorn, knapweed control in pasture, 2,500 2,500
In forested buffer and on dam
Buckthorn, knapweed and swallow 600 600
wort control in pasture: follow-up
Buckthorn control in buffer zone 0 1,500
Subtotal: 4,850
Expenditures in 2018:
Landscape Stewardship, Inc.
Black swallow-wort control in pasture 250 250
Buckthorn, knapweed control in pasture, 2,500 2,500
In forested buffer and on dam
Buckthorn, knapweed and swallow- 600 600
wort control in pasture: follow-up
Subtotal: 3,350
Total: $12,800 $12,800