Rocky Hill Greenway Zewski-Easthampton Rd ecological assessment 7.2.20151
Zewski Ecological Assessment July 2015
An Ecological Assessment of the 16-Acre Zewski Parcel
By Laurie Sanders, M.S.
Overview
Located along Route 10 and
zoned commercial, the 16-acre
Zewski property has been on
and off the market for more
than two decades (Fig. 1).
Over those years, various buy-
ers have considered developing
the site, including in 2005
when a large business park was
proposed on this parcel and the
land to the south and west.
Commercial investors, how-
ever, haven’t been the only
ones looking at this piece of
land. Ever since a large ‘For
Sale’ sign went up along Route 10 in the 1980s, conservation-minded residents and MassAudubon have
been interested too. In their case, the main
reasons were the property’s proximity to Ar-
cadia Wildlife Sanctuary, the presence of
vernal pools in the vicinity, and last but not
least, the land’s location within a wildlife
corridor that extends from the Mount Tom
Range to the foothills of the Berkshires (Fig.
2). More recently, acquisitions of conserva-
tion land in Northampton—including the
wooded parcel immediately north in 2014—
have made this property even more attractive
from a conservation perspective (Fig. 3).
In addition, based on field work for this re-
port, the property has other conservation
benefits as well. If acquired as conservation Figure 2: The property lies within a mostly forested wildlife corridor
that extends from Mount Tom to the Sawmill Hills and beyond.
Arcadia Wildlife Sanctuary
Zewski
Figure 1: The Zewski property is located along Route 10 and adjoins the Rocky Hill
Greenway.
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Zewski Ecological Assessment July 2015
land, it would
ensure the perma-
nent protection of
(1) an undevel-
oped drumlin, a
regionally un-
common geologic
feature; (2) his-
toric cultural fea-
tures, including a
stretch of stone-
wall, evidence of
an historic rock-
splitting tech-
nique, and barbed
wire and old wire
pasture fencing; and (3) habitat for wildlife and
plants, including what appears to be a Watch-Listed
plant species, at least four bird species in decline
(e.g. scarlet tanager, black-and-white warbler, wood
thrush, etc) and non-breeding habitat for vernal
pool species.
The remainder of this report provides a more de-
tailed ecological assessment of the Zewski property,
including information about its geology, soils and
land use history.
Geology & Soils
Aside from a band of thinner till along Route 10,
most of the Zewski property is underlain by a gla-
cial feature known as a drumlin (Fig. 4). Drumlins
are typically shaped like elongated ovals and are
oriented in the direction that the continental glacier
once flowed. They are composed of densely com-
pacted glacial till and are literally “rocky hills.”
Early settlers recognized this fact and the 1831 map
of Northampton shows not one, but two different
nearby drumlins named “Rocky Hill” (Fig. 5). The
drumlin below the Zewski property never had its
Figure 3. The Zewski property in context to other protected, wildlife or cultural lands, with MA Audu-
bon’s Arcadia Wildlife Sanctuary (bright purple), City-owned conservation land (pink), state hospital
land (olive), and the nearby golf course, private conservation restrictions and APRs (orange). Hatched
lines indicate the estimated habitat for a rare species, according to MA NHESP.
Figure 5. The 1831 map, with two Rocky Hills circled in red.
Figure 4. This image shows the surficial geology of the
Zewski property, where the lighter green color is unsorted,
thin glacial till, the darker green is drumlin (thick till), and the
blue areas are Glacial Lake Hitchcock clays.
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Zewski Ecological Assessment July 2015
own place name, but the presence of drumlins in the
vicinity is the reason behind names like Rocky Hill
Road and Rocky Hill Brook.
Another interesting aspect is that the Zewski drum-
lin is found within a cluster of drumlins (Fig. 6). In
this case, there are seven others nearby. Only four
other drumlins occur in Northampton outside of this
cluster (e.g. Round Hill, Baker Hill, Childs Park,
High Street in Florence).
Perhaps even more noteworthy from the perspective
of a future educational opportunity is that the
Zewski drumlin is one of only two in the City that
remains free of buildings or roads. (The only other
undeveloped drumlin is now managed by Smith Vo-
cational as pasture and off Rocky Hill
Road.)
Glacial Lake Hitchcock to the Present
After the continental glacier retreated
some 15,000 years ago, a long, narrow
glacial lake filled the Connecticut River
valley. Known as Glacial Lake Hitch-
cock, it lasted for about 3,000 years and at
its maximum height, it reached what is
now our 100 meter contour elevation. At
that time, the Zewski property, which is
just under 100 meters, was shallowly cov-
ered by the lake (Fig 7.). When Lake
Hitchcock’s level dropped, the top of the
drumlin was exposed and became a nar-
row peninsula/island in the shallow waters of the lower lake known as Lake Hadley.
Since the lake disappeared some 10,000 years ago, the thin layer of fine lake sediments has washed off
the top of the drumlin and down the lower slopes. The enriching effect of the glacial lake clays is evi-
dent in the plant community that has developed on the land east of the toe of the exposed drumlin. Be-
cause clay particles have the capacity to bind nutrients like calcium and magnesium, their presence has
added to the soil’s overall fertility and explains why species that require rich soils, like horse balm
(Collinsonia canadensis), baneberry (Actaea sp.) and wild geranium (Geranium maculatum), occur in
Fig. 6. Although many drumlins are isolated, they are also
often found in clusters or “swarms.” This is true of the
drumlin underlying much of the Zewski property (arrow).
Fig. 7: At its highest, Glacial Lake Hitchcock extended to the present day
300-foot contour interval and covered all of the land shown in blue and
aquamarine. When it dropped to about 200 feet in elevation, it covered the
area marked in blue and exposed the ridge and sideslopes of the drumlin
that may be acquired.
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Zewski Ecological Assessment July 2015
these areas.
Human History
Rising to a height of
nearly 100 meters, the
top of this drumlin
may have been—and
probably was—a fa-
vorite lookout point
for generations of na-
tive people (Fig. 8).
With the aid of fire,
the Nonotuck would
have kept its summit
cleared and open,
which would have given
them an impressive
panorama that took in the meadows along Connecticut and Manhan Rivers, the Connecticut River, and
the Mount Tom and Holyoke Ranges.
Figure 8. This 3-D view from the top of the drumlin that simulates what native people would
have seen minus, of course, the buildings and roads.
Figure 9: (A) The remains of a very loosely constructed
stone wall, probably done before 1830, with a dead red ce-
dar in the center. Red cedar requires open, sunny conditions
to germinate and because it is not eaten by cattle, it fre-
quently grows up in old pastures. (B) Strands of barbed
wire can be seen in this cedar trunk along the property’s
southern boundary. Regular wire fencing can be found on
the north boundary. (C) One of two bored holes that were
found in an area with busted up rock. These holes were cre-
ated using the plug-and-feather method of splitting stones, a
technique that was used by farmers from the 1774-1810.
B
C
A
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Zewski Ecological Assessment July 2015
Colonial America-Present
When the first English came
from Springfield and Connecti-
cut to settle Northampton in
1654, they probably followed a
Native American trail that
looped around the oxbow and
continued north to Northamp-
ton. It is also very likely that
the trail followed the path
where Route 10 now lies,
which means they would have
passed very close to the
Zewski property.
What this property may have
looked like or been used for in
the 1600s and 1700s is un-
known, but by the early 1800s, a much clearer picture emerges. The presence of a short stretch of mod-
est stonewall provides solid evidence that by then the land was cleared and being used as pasture (Fig.
9). The land continued to be used as pasture into the 20th century. But by the early 1950s, most of the
land had been allowed to grow back into forest and only the stretch along Route 10 and near the top of
the drumlin remained clear and open (Figs. 10, 11).
Since the 1960s, little
activity has taken place
on the land. At some
point a section of slope
along Route 10 was
carved into, possibly for
fill for a reconstruction
of Route 10, and during
the last 15 years, some
of the larger trees along
the property’s northern
boundary were har-
vested. Today that his-
tory of cutting is obvi-
ous; there are the re-
mains of cut stumps, old
Fig. 10: The Zewski property, as it appeared in 1952. Note the open clear near the
summit and along Route 10. The land to the west was still open and not yet a golf
Figure. 11: Two larger and much older trees that were left to grow to help serve as boundary
markers can be found on the property’s southern boundary. Note the presence of lower
branches on one of the trees; this is a clear indication that it grew up in a pasture.
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Zewski Ecological Assessment July 2015
Today the Zewski
property is entirely
forested—a mix of
deciduous trees,
hemlock and pine.
The former gravel
pit to the south is
once again com-
pletely forested as
well.
By 1965, when this
photo as taken, the
Zewski property
was no longer being
used as pasture and
the former clearings
had grown into for-
est. By then, Pine
Grove golf course
had been built and
the property to the
south had been
cleared and was
being mined for
gravel.
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Zewski Ecological Assessment July 2015
wood roads, skidder scars and an abundance
of younger saplings.
Ecology
Understanding the site’s underlying geology
and land use history is key to understanding
its habitat diversity and current vegetation
patterns. In general, the property can be di-
vided into four upland community types (Fig.
12) and two small wetland areas.
Uplands
U-1: Beginning along Route 10 is a forested
stretch of uplands. Parts of this hillside were
cut into during the last fifty years and there is
an old broad swale that was eroded naturally by groundwater and seeps. Due to natural seeps and the
presence of an intermittent stream, this area has moister soils and based on MA NHESP’s Natural Com-
munities classification system it could be very loosely characterized as a “forest seep community” in the
early-mid succession. As is typical of that natural community type, the most common canopy species
include red maple, black birch, cottonwood, with lesser amounts of red oak. The understory vegetation
in this section is lush and dominated by spotted touch-me -not, Virginia creeper, and sensitive fern. Not
surprisingly, invasive non-native
plants have also gotten a foothold
here and in some areas, they are
abundant, especially near the edge
of Route 10. They include black
locust, Norway maple, privet, Mor-
row’s honeysuckle, multiflora rose
and Asiatic bittersweet.
U-1
U-2 U-3
U-4
W-1
W-2
Figure 12. Natural Communities on the
Zewski Property
1: Successional “Forest Seep Community”, with abun-
dant invasive species
2: Mixed Forest/Successional—with abundant invasive
species
3: Mixed hardwood, with red oak/black birch/hickory
and sugar maple
4. Oak/white pine/hemlock community
W-1: Red Maple swamp
W-2: Intermittent stream
A steeper, altered hillside can be found not far from Route 10. Not
the abundance of exposed boulders and stones. In the foreground is a
Norway maple.
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Zewski Ecological Assessment July 2015
U-2: Moving uphill, there is a clear break in the slope and the slope
becomes more gentle. This area also has fairly moist soils. The rea-
sons why are two-fold. Partly it is because rainwater cannot soak
down through the more compact till layer that forms the drumlin, so
runs along the at or near surface until it reaches the toe of the slope,
where it either emerges as groundwater or infiltrates into the less
dense former shoreline of the glacial lake, which includes both thin-
ner (i.e. less dense) till deposits and glacial clays. The drumlin’s
compact till, however, continues below the thinner till, which causes
a perched water table in this area—i.e. wetter soils. What’s also different here is that this more gentle
slope has richer soils due to the presence of accumulated fine sediments (silts and clays) from the glacial
(A) Near Route 10, an intermittent stream has carved a broad, lush basin. (B) Here and there on the property are areas where the
soils have been altered by a backhoe. This is one of those sites, but now filled with a handful of wetland species and surrounded
by wild sarsaparilla and other plants more typical of drier, upland soils.
(A) Above the first rise is a plateau where you can find big patches of hayscented
fern growing below a mixed deciduous forest. (B) Because this area was kept open
for pasture longer, the forest here is fairly young (~50 years) and more of a tangle.
(C) Grape vines are common along the plateau and in the till soils below the drum-
lin.
A B
A B
C
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Zewski Ecological Assessment July 2015
lake. Because of these two conditions (fertility
and moisture), the plant diversity in this area is
higher than elsewhere on the property and in-
cludes species such as wild geranium, jack-in-the
-pulpit, baneberry, horse balm, grape and sugar
maple—all of which only grow in neutral, fertile
soils. Unfortunately, because this area was also
cleared within the last sixty years, it also has
been more vulnerable to invasion by non-native
plants. Not only are Asiatic bittersweet and mul-
tiflora rose common here, but you can also find
lesser amounts of swallowwort, autumn olive,
privet and Japanese barberry.
U-3: Heading west and climbing up the drumlin,
the slope ascends steadily and swiftly. The soils in this band are drier and more acidic, stones are com-
mon, and the forest is older and more open. Red oak and black birch are more common in the overstory,
while the percentage of red maple is less than in zone U-2. Other common species here include witch
hazel, sassafras, Canada mayflower, starflower, wild sarsaparilla, Virginia creeper, hayscented fern, lady
fern, Christmas fern, and New York fern.
U-4: At the summit of the drumlin, the land flattens out. The soils here are even drier and acidic, and the
canopy transitions to mostly red oak, hemlock, and white pine, with lesser amounts of black birch, white
birch and black locust. The shrub layer differs too and includes large patches of mountain laurel, smaller
clones of lowbush blueberry and dwarf blueberry, as well as scattered maple-leaved viburnum and witch
hazel. Below the areas of deciduous forest are broad swaths of hayscented fern, while the shaded under-
The forest on the slopes of the drumlin is older and the underly-
ing soils are drier and more acidic. One result is that the under-
story is more open. It is also almost entirely free of non-native
plants.
The top of the drumlin includes a mix of oak, hemlock and white pine. Below the oak dominated woods, mountain laurel is
common. In areas where hemlock dominates, there is almost no understory….for now. All of these hemlocks are dying from
woolly adelgid.
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Zewski Ecological Assessment July 2015
story below the hemlock and mountain laurel are
virtually free of any herbaceous ground cover.
Wetlands
W-1: Dropping down into the saddle of the drum-
lin are the headwaters of an intermittent stream
that joins a small, unnamed perennial stream,
which drains the golf course property and ulti-
mately flows into the Manhan River. The land in
this section of the property is slightly swampy and
includes a typical mix of wetland ferns (cinnamon,
interrupted, sensitive), wildflowers (skunk cabbage,
gold thread, Indian cucumber root), shrubs
(winterberry, spicebush, mountain laurel) and red
maple. Just west the property’s boundary is a shallow
stretch of open water, which may function as a vernal pool.
W-2: The only other wetland on the property is a seep that
occurs near Route 10, not far from the parcels southwestern
boundary. Over the last 10,000 years the groundwater in this
area has carved out a large, bowl-shaped amphitheatre.
(A) The arrow overlaid on this 1939 topographic map points to the
saddle that lies in the middle of the drumlin. The water that gathers
here drains to the south and joins the brook that flows through the golf
course and then wangles east to the Manhan River. (B) the headwater
wetlands/intermittent stream at the property’s northwestern boundary.
(C) The seep near Route 10, covered with touch-me-not and lady fern.
Young saplings and a tree trunk scarred by a skidder can be
found on the property’s northern border. Within the last 15
years, a logging operation on the adjacent property led to some
cutting along the northern boundary of the Zewski property in
zones 2, 3 and 4. Today, in addition to the decomposing cut
stumps, this section has an abundance of young saplings
(mostly black birch) and the remains of two wood roads.
A B
C
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Zewski Ecological Assessment July 2015
Rare Species, Priority Habitat, Vernal Pools and Species in Decline
Although the Zewski property falls outside of any designated MA NHESP polygon, it does lie close to
BioMap2 Core Habitat, Critical Natural Landscape, Aquatic Core Habitat, and Priority Natural Habitat
for a Rare Species. It does not, however, have a vernal pool. The certified vernal pool shown on the
NHESP certified vernal pool datalayer is actually not on this parcel, but on private land to the south-
west. Nevertheless, this land does provide valuable non-breeding habitat for spotted salamanders and
wood frogs, which spend all but two weeks of their adult lives living away from their breeding pools and
in the surrounding uplands.
In addition, this relatively young forest is contiguous to other for-
ested lands, which makes it more valuable to animal species that are
forest specialists or use forests transitionally. During the field work
for this report, sign of bear, deer, and raccoon was observed and sev-
eral different species of birds were heard or seen, including four spe-
cies (wood thrush, scarlet tanager, black-throated blue warbler, black
-and-white warbler) that are declining (MA
Audubon, State of the Birds, 2013). In addition,
a preliminary botanical list generated 75+ spe-
cies of plants, including a small patch of pinx-
terflower (tentatively identified as Rhododen-
dron periclymenoides), a Watch-listed species.
A wood thrush, a long distant migrant declining due to
habitat fragmentation, was seen on the Zewski property.
(B) Indian pipe was one of the 75+ plant species seen on
the property. (C) “Hidden biodiversity” like this cluster of
mushrooms also survive on the Zewski property.
A
B
C
C
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Zewski Ecological Assessment July 2015
Qualifications: Laurie Sanders is a field biologist and naturalist with an M.S. from the University of
Vermont’s Field Naturalist Program and an A.B. from Smith College. She lives in Westhampton, MA
and in 2014-2015 completed an ecological assessment of all of Northampton’s city-owned conservation
land.
Sources
This report is based on field work (June 27, 2015), data from MA GIS, MA Audubon’s State of the
Birds (2013), a report by Molly Hale (2005), and MA NHESP’s Classification of Natural Communities
of Massachusetts (2005).
All photos by (c) Laurie Sanders.
A “tireless songster”, this red-eyed vireo was feeding
chicks on the property in June 2015.