Impacts of contrasting land-use history on composition, soils,and development of mixed-oak, coastal plain forests on Shelter
Island, New York
Marc D. Abrams1,2 and Vanessa L. W. HayesSchool of Forest Resources, 307 Forest Resources Building, Penn State University,
University Park, PA 16802
ABRAMS, MARC D. AND VANESSA L. W. HAYES (School of Forest Resources, Forest Resources Building,Penn State University, University Park, PA 16802). Impacts of contrasting land-use history on composition,soils, and development of mixed-oak, coastal plain forests on Shelter Island, New York. J. Torrey Bot. Soc.135: 37–52. 2008.—The Mashomack Preserve on Shelter Island, New York contains one of the premier oak-dominated coastal plain forests in the northeastern U.S. It represents a unique opportunity to study woodyspecies in juxtaposed forests that differ primarily in past land-use (logging versus agriculture). We researchedhow contrasting land-use history affected: 1) tree species composition, size, and age structure; 2) soilchemistry and morphology; 3) the dominance of Smilax, a native invasive shrub; and 4) the historicalecology and successional pathways. Randomly located plots were sampled for vegetation and soils in theunplowed interior forest versus the maritime forest that was cleared and/or plowed for agriculture andgrazing in the 18th and 19th centuries and then abandoned after 1870. The upper soil profile was examined forsoil nutrients and pH, the presence/absence of a plow layer (Ap) and for soil charcoal. Tree cores (N 5 130)were taken across both forest types to include the full range of species and diameter size classes to assesstemporal and spatial variation in recruitment. Maritime forests are closer to the ocean shore and aredominated by Quercus velutina, Sassafras albidum, Carya glabra, and Q. alba, whereas the interior forests aredominated by Q. velutina, Acer rubrum, C. glabra, and Q. prinus. The interior forest plots appear to havecontinually supported forests, have soils that are somewhat doughtier and less fertile, and lack a plowedhorizon, but have frequent soil charcoal as compared with the maritime forest. Formerly plowed and grazedmaritime soils are more fertile and Q. alba has greater importance, while Q. velutina has lower importance.Following agricultural abandonment, the maritime forest understory became dominated by thickets ofSmilax and presently has lower tree diversity than interior forests. Tree regeneration is sparse in both foresttypes due, at least in part, to intense browsing by white-tailed deer (Odocoileus virginianus). The interiorforest exhibits a predictable successional pathway from mixed-oak to A. rubrum and Fagus grandifolia, whichis not apparent in the maritime black oak forests. We believe that differences in overstory and understorycomposition, species diversity, and successional pathways between the two forest types can be mainlyattributed to contrasting land-use history. Smilax is a super-dominant species that has profoundly influencedmany ecological processes on the preserve and if left unchecked will continue to do so long into the future.
Key words: biogeography, disturbance, fire, invasive, plowed layer, Smilax, white-tailed deer.
The natural distribution or biogeography of
plant species around the world has primarily
been studied in relation to variation in climate,
soils, and topography (Eyre 1963, Whittaker
1975, Ellenberg 1995). For example, the
Holdridge (1967) triangle separates world-
wide vegetation biomes by precipitation,
temperature, and humidity province. Eyre
(1963) describes the relationship of vegetation
and soils for various regions of the world,
including temperate, boreal, and tropical
biomes. Using gradient analysis, Whittaker
(1975) was able to separate vegetation types by
topography, elevation, and soils in montane
regions of the eastern and western U.S. More
recently, however, researchers have identified
land-use history as an important determinant
of vegetation pattern in many world-wide
ecosystems (Foster 1992, Orwig and Abrams
1994, Verheyen et al. 1999, Dahlstrom et al.
2006). In the northeastern U.S., forest that
developed on plowed soils following agricul-
tural abandonment support different trees
species and abundances when compared with
nearby unplowed soils (Glitzenstein et al.
1990, Motzkin et al. 1996). Land-use history
has also been reported to impact soil chemistry
and nutrient cycling processes (Glatzel 1991,
Connell et al. 1994, Verheyen et al. 1999). In
1 Author for correspondence. E-mail: [email protected]
2 The Nature Conservancy Mashomack Preserveand Eppley Foundation provided funding for thisstudy. We want to thank Barnaby Friedman forproducing several of the GIS maps used in thisstudy, Mike Scheibel for his help with experimentaldesign and field data collection, and along withMichael Laspia and Marilyn Jordan, for their helpwith data interpretation.
Received for publication October 27, 2007, and inrevised form January 2, 2008.
Journal of the Torrey Botanical Society 135(1), 2008, pp. 37–52
37
western Belgium, cultivated soils had higher
pH, Ca, and P than forests and grasslands
(Verheyen et al. 1999). However, impact of
land-use history on soil chemistry seems to be
more profound in European studies than it is
in the U.S. (Motzkin et al. 1996, Koerner et al.
1997, Flinn et al. 2005). This may be due to the
comparatively short history of post-European
settlement (150–400 years) in the U.S. relative
to Europe (5000+ years; Foster 1992). None-
theless, there is a relative scarcity of detailed
studies on the impacts of land-use history on
plant biogeography and soils, particularly in
the U.S.
Oak forests dominate much of the eastern
deciduous forest biome and have done so for
much of the Holocene epoch (Braun 1950,
Barnes 1991, Webb 1988). The mechanism
underlying the long-term importance of oak in
eastern forests has been the subject of consid-
erable amount of research (Abrams 2003,
McEwan et al. 2007). It has been hypothesized
that oak forests have developed and been
maintained by periodic, low intensity, under-
story burning (Lorimer 1985, Abrams 1992).
Periodic fire, coupled with logging activities,
has allowed the relatively fire resistant and
light demanding species, such as oak, hickory,
and pine to survive (Abrams 1996, 2003).
Moreover, later successional, fire sensitive tree
species readily invade and dominate most
upland oak forests in which fire has been
suppressed during the 20th century (Lorimer
1984, Abrams 1992, 1998). The magnitude of
anthropogenic disturbances in North Ameri-
can forests changed dramatically following
European settlement. These included extensive
logging and land clearing, catastrophic fire
followed by fire suppression, agriculture often
followed by agricultural abandonment, the
introduction of exotic insects and diseases, and
spread of exotic and native invasive plant
species (Foster 1992, Abrams 2003). All of
these have led to unprecedented and rapid
changes in forest composition and structure.
In many respects, the landscape has undergone
a nearly complete transformation in the years
following European settlement (Whitney 1994,
Foster et al. 1998). Thus, land-use history
apparently represents a highly pervasive, yet
understudied, force affecting forests of the
eastern U.S. (Russell 1997).
The Nature Conservancy’s Mashomack
Preserve on Shelter Island, New York contains
one of the premier oak-dominated coastal
plain forests in the northeastern U.S., but little
is known about its forest composition, ecolog-
ical history, or the impacts of land-use history
on vegetation, plant succession, and soils.
Indeed, very little detailed information of this
type exists for northeastern coastal plain oak
forests (Ehrenfeld 1982, Clark 1986, Motzkin
et al. 2002). Two forested areas exist on
Mashomack that primarily differ in their
land-use history (logging versus agriculture).
After agricultural abandonment starting in
1870, one forest area formed with a dense
understory of greenbriar (Smilax spp.), a
native invasive shrub. A second forest area
on Mashomack was repeatedly cut and
exposed to period fire, but was never plowed.
The contrasting land-use in edaphically
similar and juxtaposed forests creates a unique
opportunity to study the impacts of anthro-
pogenic disturbances on the plant geography
and succession. The objectives of this research
are to characterize the impacts of land-use
history on plant geography and soils and
includes: 1) tree species composition, size, and
age structure; 2) soil type, texture, and
chemistry, including the presence or absence
of an Ap (plowed) surface horizon and soil
charcoal from past fires; 3) the impact of
Smilax cover on forest composition; and 4) the
historical development and successional trends
in the study area forests.
Materials and Methods. STUDY AREA DE-
SCRIPTION. The 810 ha Mashomack Preserve is
located on the coastal plain of Shelter Island,
New York (41.106uN, 72.233uW) off the
eastern end of Long Island (Fig. 1). Two
major oak-dominated areas on Mashomack
are the interior forest (270 ha) and the
maritime forest (235 ha; Fig. 1). The interior
forest forms the central core of Mashomack
and was not used extensively, if at all, for
agriculture. This is evident from an 1855
survey showing the forested interior of Ma-
shomack surrounded by cleared fields used for
agriculture (Fig. 1). Nonetheless, the interior
forest was logged and burned several times
since European settlement starting in the early
1600s (Weaver 1990). In contrast, the maritime
forest developed on those cleared plots as a
result of agricultural abandonment after 1870.
The extent of the maritime forest is easily
recognizable today because it is covered in
dense thickets of greenbriar (Smilax spp.) not
present in the interior forest. The naming of
38 JOURNAL OF THE TORREY BOTANICAL SOCIETY [VOL. 135
FIG. 1. Distribution of the major forests types on the Mashomack Preserve, showing the location ofShelter Island on the east end of Long Island, New York, the present boundary between the interior andmaritime forest types, the location of the 53 permanent plots within the interior forest (designated by I) andmaritime forest (M), and the 1855 forested (shaded interior) and cleared plots (white) with boundaries basedon a geodetic survey of Mashomack (lower left panel; Shalowitz 1964).
2008] ABRAMS AND HAYES: IMPACTS OF LAND-USE HISTORY 39
the two forests types on Mashomack as
interior versus maritime is done only for the
convenience of this study; in the broader sense
both types are, in fact, maritime or coastal
plain forests.
The average annual high and low tempera-
ture on Shelter Island is 21uC and 7uC,
respectively. Average annual precipitation
totals 116.6 cm, which is evenly dispersed
throughout the year (monthly precipitation
averages range from 8.0 to 11.7 cm). Influen-
tial weather disturbances include high winds
and hurricanes, the most severe of which
occurred in 1893, 1938, and 1985 (Gornitz et
al., 2002). The average elevation on the island
is 15 m above sea level. All of the soils found
on Shelter Island are typical of terminal
moraines, including Montauk, Riverhead,
and Plymouth sandy loams, as well as Carver
and Plymouth sands (Warner et al. 1975). In
general these soils series are well-drained to
excessively well-drained, have low natural
fertility, and moderately coarse to coarse
texture. The Montauk sandy loam soil is the
most prevalent throughout the Mashomack
Preserve, while the Carver and Plymouth
sands are generally found on higher elevation
sites.
All field work was completed between
March and December 2006. Fifty-three ran-
domly located sampling points in the interior
forest (30 plots) and maritime forest (23 plots)
were used for vegetation and soil analysis
(Fig. 1). Fewer plots were used in the maritime
forest because it covered less area on the
preserve. A 400 m2 circular plot was used at
each sampling point to inventory all tree
species $ 2.5 cm dbh (diameter at breast
height) and saplings (tree species . 1.5 m in
height and dbh , 2.5 cm). Species, diameter,
and crown class were recorded for all trees.
Classification of tree crowns into four catego-
ries (dominant, codominant, intermediate, and
overtopped) was based on canopy position.
One hundred and thirteen tree cores were
taken at 0.5–1.0 m height across both forest
types to include the full range of species and
diameter size classes. This information was
used to determine age structure, temporal, and
spatial variation in tree recruitment, and forest
succession. All cores were brought back to
Penn State University, sanded with increas-
ingly fine sand paper, and analyzed under a
microscope for total age to pith (first year
growth) by counting tree rings. In cores where
the pith was missed (i.e., pith located outside
the exact center of the tree), simple geometry
and the early growth rate of the tree were used
to estimate total age. Using concentric plots at
the center of each sampling point, tall
seedlings $ 0.5 m and , 2.0 m in height were
counted by species in 50 m2 plots at each
sample point. Shrub cover was estimated into
cover classes (0–5%, 5–25%, 25–50%, 50–75%,
75–95%, and 95–100%) by species in the 50 m2
plots. For each forest type, tree data were used
to calculate a relative importance value from
the average of the relative frequency, relative
density, and relative dominance (basal area;
Cottam and Curtis, 1956). Species richness
(the average number of species per plot) and
the Shannon-Weaver Index of Diversity (2S
pi log pi, where pi 5 tree species basal area)
were calculated for the two forest types
(Whittaker 1975).
A soil sample was taken from the top of the
B horizon (at approximately 10 cm in depth in
the zone of illuviation) at each of 53 sample
points used for vegetation sampling. These
samples were air dried and then brought to the
soil analysis laboratory at Penn State Univer-
sity for chemical analysis of pH, hydrogen,
phosphorus, potassium, magnesium, calcium,
and cation exchange capacity (CEC). Cation
exchange capacity was determined by the
summation methods, pH was determined in
water, and P, K, Mg, and Ca were determined
using the Mehlich 3 technique (Wolf and
Beegle, 1995). In addition, at 27 of the sample
plots distributed throughout both forest types,
the upper soil profile was examined for the
presence/absence of a plow layer (Ap) and for
coarse soil charcoal fragments $ 2 mm. Soils
and vegetation data were tested for normality
and then analyzed using ANOVA, t-tests, and
Pearson product-moment correlation. Plant
nomenclature follows Gleason and Cronquist
1991.
Results. FOREST COMPOSITION AND STRUC-
TURE. The interior forest of the Mashomack
Preserve is dominated by black oak (Quercus
velutina Lam.), red maple (Acer rubrum L.),
pignut hickory (Carya glabra (Mill.) Sweet),
and chestnut oak (Quercus prinus L.; Table 1).
A total of 12 tree species were recorded in the
30 sample plots. The total density and basal
area is 547 trees per ha and 27 m2 per ha,
respectively. Black oak has a relative impor-
tance value (RIV) of 20%, occurring in 22 of
40 JOURNAL OF THE TORREY BOTANICAL SOCIETY [VOL. 135
the 30 sample plots, and has the highest
dominance (or basal area) of any tree species.
Black oak’s density is second only to red
maple. Red maple has a RIV of nearly 20%, it
occurred in 23 sample plots and has a density
of 150 trees per ha. Pignut hickory has a
relatively high importance value, but a low
dominance is a result of its being primarily a
small diameter tree. In contrast, the impor-
tance of chestnut oak and white oak (Q. alba
L.), is due to having mostly large diameter
trees. Dogwood (Cornus florida L.) is the fifth
rank dominant due to having a large number
of small diameter trees. Beech (Fagus grand-
ifolia Ehrh.) is the seventh most important
species. The five remaining tree species (north-
ern red oak, Quercus rubra L.; sassafras;
Sassafras albidum (Nutt.) Nees; sweet birch;
Betula lenta L.; shagbark hickory, Carya ovata
(Mill.) K. Koch; and black cherry, Prunus
serotina Ehrh.) occur relatively infrequently.
The interior forest at Mashomack has attri-
butes of both the oak-beech and oak-hickory-
dogwood types previously described for Long
Island (Greller 1977, Greller et al. 1982).
A total of 12 tree species were also recorded
in the maritime forest that is dominated by
black oak, sassafras, pignut hickory, white
oak, and black cherry (Table 2). The total
density and basal area of all surveyed trees is
346 trees per ha and 21.5 m2 per ha, respec-
tively. These values are much lower than those
recorded in the coastal interior forest. Black
oak has a RIV of 32.7%, occurring in 20 of the
23 sample plots, and had the highest domi-
nance of any tree species. Sassafras has the
Table 1. Total and relative frequency (number of sample plots), density (total number of trees), anddominance (basal area) and relative importance value for all tree species recorded in the interior forest at theMashomack Preserve. Relative importance value is the sum of the relative frequency, density, anddominance divided by three for each tree species.
SpeciesFrequency(30 plots)
Density(stems/ha)
Dominance(m2 ha21)
Relativefrequency
Relativedensity
Relativedominance RIV
Q. velutina 22 94.17 7.40 15.49 17.04 27.45 20.00A. rubrum 23 150.83 4.43 16.20 27.30 16.42 19.97C. glabra 22 87.50 2.83 15.49 15.84 10.48 13.94Q. prinus 19 52.50 4.95 13.38 9.50 18.36 13.75C. florida 21 88.33 0.58 14.79 15.99 2.16 10.98Q. alba 17 21.67 3.58 11.97 3.92 13.27 9.72F. grandifolia 8 33.33 2.02 5.63 6.03 7.48 6.38Q. rubra 4 0.83 0.69 2.82 1.21 2.57 2.20S. albidum 2 9.17 0.15 1.41 1.66 0.55 1.20B. lenta 1 5.83 0.26 0.70 1.06 0.97 0.91C. ovalis 2 1.67 0.08 1.41 0.30 0.28 0.66P. serotina 1 0.83 0.003 0.70 0.15 0.01 0.20Total 142 546.67 26.96 100% 100% 100% 100%
Table 2. Total and relative frequency (number of sample plots), density (total number of trees), anddominance (basal area) and relative importance value for all tree species recorded in the 23 sample plots inthe maritime forest at the Mashomack Preserve. Relative importance value is the sum of the relativefrequency, density, and dominance divided by three for each tree species.
Frequency(23 plots)
Density(stems/ha)
Dominance(m2 ha21)
Relativefrequency
Relativedensity
Relativedominance RIV
Q. velutina 20.00 81.52 10.97 23.53 23.58 51.05 32.72S. albidum 15.00 85.87 2.67 17.65 24.84 12.44 18.31C. glabra 9.00 45.65 2.30 10.59 13.21 10.68 11.49Q. alba 7.00 36.96 3.23 8.24 10.69 15.03 11.32P. serotina 13.00 41.30 0.51 15.29 11.95 2.37 9.87C. florida 8.00 18.48 0.18 9.41 5.35 0.85 5.20A. rubrum 4.00 16.30 0.39 4.71 4.72 1.83 3.75Q. prinus 3.00 7.61 0.69 3.53 2.20 3.21 2.98Q. stellata 2.00 4.35 0.24 2.35 1.26 1.13 1.58A. laevis 2.00 5.43 0.06 2.35 1.57 0.26 1.40F. grandifolia 1.00 1.09 0.23 1.18 0.31 1.09 0.86C. ovata 1.00 1.09 0.02 1.18 0.31 0.07 0.52Total 85.00 345.65 21.50 100% 100% 100% 100%
2008] ABRAMS AND HAYES: IMPACTS OF LAND-USE HISTORY 41
second highest RIV from a high density of
small to intermediate size trees. Pignut hickory
has the third highest RIV of 11.5%, and is
present mainly as a relatively small diameter
tree. White oak ranks fourth over-all in RIV
although its dominance is the second highest
of any species as a result of having mostly
large diameter trees. Black cherry is the fifth
most important species, but has a very low
basal area of 0.5 m2 ha21. The seven remaining
tree species (dogwood, red maple, chestnut
oak, post oak (Quercus stellata Wangenh.),
serviceberry (Amelanchier laevis (Michx. f.
(Fern.)), beech and shagbark hickory) have
relative importance values ranging from 0.5 to
5.2%. The maritime black oak forest has
increased black oak and sassafras and de-
creased red maple, dogwood, chestnut oak,
and beech when compared with the interior
forest. It has elements of other maritime
forests described for Long Island, including
the presence of Smilax (Greller 1977).
The diversity of overstory trees in the
interior forest is significantly higher (P 5
0.006), with a species richness of 4.77 6 0.20
(versus 3.74 6 0.29 in the maritime forest) and
a Shannon-Weaver Index of 0.915 (versus
0.290 in the maritime forest).
In the interior forest, the three largest
diameter classes (50–80 cm) contain relatively
few trees and are dominated by beech, black
oak, white oak, and chestnut oak (Fig. 2). The
three intermediate diameter classes (20 to 49.9
cm) are dominated by black oak, chestnut
oak, hickory, and red maple. The two smallest
diameter classes (2.5 to 19.9 cm) are primarily
red maple, dogwood, and hickory; although,
black oak has 32 trees in the 10–19.9 cm class
and beech has 18 trees (most appeared to be
root suckers) in the 2.5 to 9.9 cm class.
Chestnut oak and white oak have very
low representation in the smallest diameter
classes.
In the maritime forest, one very large white
oak is represented in the 90–99.9 cm dbh class
(Fig. 3). The 40–69.9 cm classes are dominat-
ed by black oak, with lesser amounts of white
oak, sassafras, and pignut hickory. Black oak
is also well represented in the 30–39.9 cm dbh
class, but shares dominance with sassafras as
well as pignut hickory, chestnut oak, and
white oak. The 10–29.9 cm dbh classes are
dominated by sassafras, pignut hickory, white
oak, and red maple, with lesser amounts of
black oak. The 2.5–9.9 cm dbh class is dom-
inated by sassafras and black cherry, followed
FIG. 2. Diameter class distribution for all surveyed trees in the 30 samples plots in the interior forest onthe Mashomack Preserve.
42 JOURNAL OF THE TORREY BOTANICAL SOCIETY [VOL. 135
by pignut hickory, dogwood, and very few
black oak and white oak.
The dominant canopy class in the interior
forest is mainly comprised of black oak,
chestnut oak, hickory, white oak, and red
maple, followed by beech (Fig. 4). The co-
dominant class is primarily red maple and
black oak, with moderate amounts of chestnut
oak and pignut hickory. Small numbers of
white oak and beech also occur in the co-
dominant class. Between the dominant and co-
dominant classes there is a large increase in red
maple, and moderate declines in black oak and
white oak. The intermediate canopy class is
dominated by red maple, with moderate
amounts of pignut hickory, black oak, dog-
wood, and beech. The over-topped canopy
class is primarily dogwood, followed by pignut
hickory, red maple, and beech. White oak and
chestnut oak are almost nonexistent in the
overtopped and intermediate canopy classes.
In the maritime forest, the dominant canopy
class has a large number of black oak, a
moderate amount of white oak, and small
numbers of chestnut oak, sassafras, and pignut
hickory (Fig. 5). The co-dominant class is
dominated by sassafras, black oak, and white
oak, with moderate amounts of pignut hick-
ory, chestnut oak, and red maple. Sassafras
also dominates the intermediate canopy class,
followed by red maple, pignut hickory, white
oak, black oak, dogwood, and black cherry.
Sassafras and black cherry dominate the over-
topped class, followed by dogwood, pignut
hickory, and serviceberry. A steady decline in
the number of black oak and white oak is
evident in the progressively lower canopy
classes that are dominated by sassafras, black
cherry, dogwood, and red maple.
The oldest trees cored in the interior forest
are a 161 year old beech, a 144 year old white
oak and a 134 year old black oak (Fig. 6). The
age structure of the remaining trees reveals
several interesting developmental patterns.
Chestnut oak dominated recruitment (n 5
14) between 1875 and 1915; in fact all the
chestnut oak sampled in the forest recruited
during this time period. Other species recruit-
ing then were white oak, black oak and beech.
Between 1915 and 1940, tree recruitment was
dominated by red maple and beech. After
1940, red maple and black oak dominated
recruitment, followed by hickory and beech.
Beech age ranged from 26 and 161 years, and
it recruited more-or-less continuously within
that timeframe.
FIG. 3. Diameter class distribution for all surveyed trees in the 23 samples plots in the maritime forest onthe Mashomack Preserve.
2008] ABRAMS AND HAYES: IMPACTS OF LAND-USE HISTORY 43
FIG. 4. Canopy class distribution for all surveyed trees in the 30 samples plots in interior forest on theMashomack Preserve.
FIG. 5. Canopy class distribution for all surveyed trees in the 23 samples plots in the maritime forests onthe Mashomack Preserve.
44 JOURNAL OF THE TORREY BOTANICAL SOCIETY [VOL. 135
In the maritime forest, black oak dominated
recruitment (n 5 22) between 1880 and 1945,
followed by chestnut oak, pignut hickory, and
white oak (Fig. 7). Between 1945 and 1975,
only one black oak tree in our sample
recruited in the forest, but an additional four
black oak recruited from 1975 to 1987.
Chestnut oak and white oak recruited between
1880–1945 and 1915–1924, respectively. Pig-
nut hickory did not obtain the maximum ages
seen in black oak and chestnut oak, but
exhibited fairly continuous recruitment from
1895 until 1980. During 1945–1987, tree
recruitment included sassafras, pignut hickory,
black cherry, and red maple, in addition to the
black oak mentioned above. Thus, recent
recruitment includes more sassafras and black
cherry, and less black oak, chestnut oak, and
white oak when compared with the early
history of the forest.
Tree regeneration numbers are very low in
both forest types. In the interior forest plots,
only eleven beech, eight dogwood, and one red
maple saplings per ha and no tall seedlings
were recorded. In the maritime forest, only 49
saplings per ha were recorded, mainly sassa-
fras and black cherry with no oaks and very
few hickories. Seventeen tall seedlings per ha
were recorded, mostly black cherry and no
oaks. In the interior forest, shrub cover
averages 41%, with huckleberry (Gaylussacia
spp.) at 26% cover and greenbriar (Smilax
rotundifolia), and blueberry (Vaccinium spp.)
each at 7% cover (Fig. 8). In the maritime
forest, shrub cover averages 80%, dominated
by greenbriar at 67%; blueberry is the second
with 8% cover, followed by bayberry (Myrica
spp.) at 2% cover. A dense thicket of green-
briar approximately a meter or more in height
exists throughout most of the maritime forest.
Because the maximum cover of a single species
within a plot is 95–100%, our sampling
protocol does not fully capture the over-
whelming density of overlapping stems for
greenbriar throughout the maritime forest.
IMPACTS OF SOIL CHEMISTRY, TYPE AND
TEXTURE. Soil pH averages 4.6 and 4.4 in the
interior forest and maritime forest, respective-
ly (Table 3). Hydrogen content (a related and
inverse measure of pH) is higher in the
maritime versus interior forest, with the
FIG. 6. Age-diameter distribution for all cored trees in the interior forest on the Mashomack Preserve.
2008] ABRAMS AND HAYES: IMPACTS OF LAND-USE HISTORY 45
exception of the Plymouth sands in the latter.
Potassium ranged from 30.0 to 38.7 ppm
across all soil types and is not significantly
different between forest types. Magnesium,
Ca, Na, and CEC is typically higher in the
maritime versus interior plots, but similar
across the various soil types within each forest
type.
Overall, both forest types are edaphically
similar. However, the interior forest contain a
greater proportion of the more xeric Plymouth
loamy sands and Carver sands than do the
maritime forests (Table 3), while the maritime
forests contain more of the mesic Montauk
loamy sands. Both forest types contain a
similar acreage of Montauk sandy loam and
Riverhead sandy loam. The maritime forests
have a lower elevation (3–13 m above sea
level) compared to the interior forests at 13–
20 m asl. Overall, plot-by-plot variation in soil
chemistry and soil type/texture had no statis-
tically significant impact on tree distribution
within or between the two forest types.
In 16 sample plots in the interior forest,
eight contained soil charcoal but all of the
tested plots were unplowed (lack an Ap
horizon; Fig. 9). In the maritime forest, only
three of eleven plots had charcoal fragments,
but all eleven plots had an Ap horizon. This
indicates that the maritime forest was primar-
ily used for agriculture or grazing and
experienced less burning. The interior forest
existed prior to 1855 (Fig. 1), was not used
extensively for agriculture, was burned peri-
odically, at least in part, and probably
remained forested since the time of European
settlement, albeit with several cutting cycles.
Within the maritime forest, soils containing a
plowed (Ap) horizon have significantly (P ,
0.05) higher concentrations of P, K, Ca, and
CEC, Mg and Na (Table 4). The importance
of white oak is 10% on plowed plots and 0%
on unplowed plots. In contrast, black oak has
significantly higher importance on unplowed
(40% importance) versus plowed (31%) plots.
Discussion. Agricultural clearing on Shelter
Island began shortly after European settle-
ment in 1640 and eventually lead to tenant
farming and livestock rearing (Weaver 1990).
The English military continued to clear the
Mashomack forest during the Revolutionary
FIG. 7. Age-diameter distribution for all cored trees in the maritime forest on the Mashomack Preserve.
46 JOURNAL OF THE TORREY BOTANICAL SOCIETY [VOL. 135
War (1776–1786). During this time, at least
3500 cords of wood (mostly white oak and
chestnut oak) were extracted for the produc-
tion of barrels. Large quantities of lumber
were also cut from 1784–1827, and by the
middle of the 19th century 2000 ha of Shelter
Island were cleared by various owners and
tenant farmers for agriculture alone. Heavy
commercial logging occurred in the 1870s–
1890s and produced slash that likely fueled a
catastrophic fire of 1902 (Weaver 1990).
These land-use history events greatly influ-
enced the present-day forests on the Masho-
mack Preserve. The ecology of oak forests in
the northeast region is thought to be closely
tied to periodic fire, past logging, and land
clearing (Lorimer 1985, Abrams 1992). In-
deed, oak species dominated tree recruitment
from approximately 1875 to 1915 in the
interior forest following widespread logging
and fire. All the chestnut oak and most of the
white oak trees in the study area date to this
FIG. 8. Dense greenbriar (Smilax) cover in amaritime black oak forest understory at Masho-mack (top panel). More open and patchy understorydominated by blueberry (Vaccinium) in the coastalinterior forest. In both examples, note the lack oftree seedlings.
Tab
le3.
Mea
nan
dst
an
dard
erro
rvalu
esfo
rso
ilp
H,
cati
on
exch
an
ge
cap
aci
ty(C
EC
),an
dca
tio
ns
for
the
majo
rso
ilty
pes
inth
ein
teri
or
an
dm
ari
tim
eb
lack
oak
fore
sts
on
the
Mash
om
ack
Pre
serv
e.N
um
ber
sw
ith
ina
row
shari
ng
the
sam
ele
tter
are
no
tsi
gn
ific
an
tly
dif
fere
nt
at
P,
0.0
5.
Inte
rio
rfo
rest
Mari
tim
efo
rest
Mo
nta
uk
fin
esa
nd
ylo
am
Riv
erh
ead
san
dy
loa
mM
on
tau
klo
am
ysa
nd
Ply
mo
uth
san
ds
Carv
era
nd
Ply
mo
uth
san
ds
Mo
nta
uk
fin
esa
nd
ylo
am
Mo
nta
uk
loa
my
san
dR
iver
hea
dP
lym
ou
thC
arv
ersa
nd
s
pH
4.5
96
0.0
5a
4.8
60.1
1a
4.5
26
0.0
9a
4.3
86
0.0
6a
4.6
26
0.0
9a
4.3
66
0.1
1a
4.4
56
0.0
8a
4.4
06
.016a
P(p
pm
)7.4
46
0.8
7a
7.8
60.6
3a
8.2
61.0
2ab
10.3
36
1.4
6b
6.2
61.0
7a
10.8
16
0.9
5b
10.5
06
1.0
6b
16.6
76
2.0
3c
K(p
pm
)30.0
06
3.9
1a
34.2
63.8
0a
31.2
63.4
0a
38.0
06
6.4
8a
33.4
63.6
8a
37.5
06
3.9
4a
38.7
06
5.6
3a
33.0
06
7.9
9a
Mg
(pp
m)
14.0
06
1.6
3a
17.8
64.7
6a
12.6
60.8
1a
17.1
76
2.3
6a
12.6
61.4
4a
32.1
96
3.0
8b
41.4
06
3.6
3b
43.0
06
4.6
3b
Ca
(pp
m)
18.0
16
3.6
1a
39.9
26
8.0
6b
18.4
26
5.2
4a
17.9
76
2.3
6a
16.8
26
3.8
7a
52.4
96
6.6
4b
58.2
16
5.2
5b
61.1
36
4.3
4b
Na
(pp
m)
10.1
86
0.4
6a
10.2
66
0.7
2a
10.0
26
1.0
9a
10.6
86
0.2
9a
8.9
60.9
0a
16.9
66
1.1
5b
27.8
86
4.0
3c
12.3
36
2.1
9a
H(m
eq/1
00g)
6.5
06
0.3
0a
6.5
46
0.3
1a
6.4
26
0.1
2a
8.5
06
0.7
0ab
6.7
86
0.5
8a
10.3
56
0.9
7b
9.4
26
0.7
5ab
11.3
06
1.4
0b
CE
C(m
eq/1
00g)
6.7
60.3
0a
6.9
66
0.4
0a
6.7
60.1
3a
8.8
36
0.7
4ab
7.0
86
0.5
8a
10.6
96
0.7
9b
10.1
66
0.8
7b
10.5
76
0.9
1b
Are
a(h
a)
85
25
35
64
70
87
63
74
2008] ABRAMS AND HAYES: IMPACTS OF LAND-USE HISTORY 47
time period. Many black oak trees recruited
between 1885 and 1890, but after a long hiatus
this species started recruiting again between
1950 and 1985. The two-phase recruitment
pattern of black oak at Mashomack is
intriguing, and suggests that black oak can
establish following large scale disturbances
(clearcutting and fire) as well as under canopy
gaps created in the mature forest (Orwig and
Abrams 1995, Abrams 1996). Indeed, high
wind is a predominant ecological factor at
Mashomack, frequently blowing down trees
and creating canopy openings (pers. obs.).
The ecology of most hickory species is
similar to that of oaks in many respects; they
are long-lived (over 300 years), have inter-
mediate shade tolerance, are early to mid-
successional, and are thought to require
periodic understory fire for long-term recruit-
ment (Burns and Honkala 1990, Orwig and
Abrams 1994). Most of the pignut hickory in
both forest types recruited during the middle
and latter stages of stand development. Recent
hickory establishment may be due to their
higher than normal shade tolerance as young
trees and/or their ability to recruit in canopy
gaps. Alternatively, the absence of older
hickory trees in the forest may be related to
their short lifespan in the mature forest canopy
at Mashomack.
Most beech recruitment in the interior forest
occurred between 1885 and 1940. Several
beech trees recruited along with the many
oaks during the earliest stage of forest
development, which indicates the ability of
beech to compete with the earlier successional
oaks. Beech is considered a late successional,
shade tolerant species and can replace oak in
the absence of fire and other disturbances
(Quarterman and Keever 1962, Monette and
Ware 1983, Abrams and Downs 1990). How-
ever, the ability of beech to replace oak may
be limited to moister sites (Seischab 1985).
Despite the drought nature of the sandy soils
at Mashomack, the low elevation and high
water table appears to be conducive to beech
success. Only three of the beech trees we aged
are less than 60 years old, and we believe that
this is due to intense white-tailed deer brows-
ing (Horsley et al. 2003). Indeed, beech
saplings dominate a deer exclosure established
in 1982, suggesting that more young beech
FIG. 9. Soil profile with Ap (plowed) horizonpresent with a homogeneous mixing of soil horizonsin the top 12–15 cm (top panel) and a soil profilewithout Ap present with a distinct upper A horizon(dark brown), middle E horizon (grey), and lower Bhorizon (light brown) (bottom panel).
Table 4. Mean and standard error values for soil pH, cation exchange capacity (CEC), and cations forplowed (Ap present) and unplowed soils within the Montauk soils group in the maritime forests on theMashomack Preserve. Numbers within a row sharing the same letter are not significantly different at P, 0.05.
Plowed Unplowed
pH 4.79 6 0.17a 4.56 6 0.07aP (ppm) 14.50 6 2.59a 5.57 6 0.72bK (ppm) 48.38 6 6.06a 25.50 6 3.65bMg (ppm) 45.00 6 9.19a 12.83 6 1.91bCa (ppm) 131.53 6 16.69a 15.70 6 3.80bCEC (meq/100g) 9.26 6 0.34a 7.30 6 0.25bNa (ppm) 16.27 6 0.87a 10.53 6 0.64b
48 JOURNAL OF THE TORREY BOTANICAL SOCIETY [VOL. 135
trees would be present if deer browsing was
reduced (Abrams and Hayes, unpublished
data).
Red maple in the interior forest dates from
1905 to 1980, with peak recruitment from 1925
to 1960. None of the existing red maple date
back to before 1900, despite the fact that this
species can live up to 200–300 years. A large
increase in red maple trees has occurred
throughout much of the eastern forest after
1900, which has been primarily attributed to
the suppression of forest fire and widespread
logging coupled with being avoided by early
loggers (Abrams 1998, 2003). It now domi-
nates many upland oak forests and is replacing
oak based on its higher shade tolerance,
among other physiological attributes (Abrams
1998). Thus, the post-1900 increase in red
maple at Mashomack is highly consistent with
this pattern seen throughout the eastern oak
forests. Red maple foliage is not a preferred
browse species for white-tailed deer, although
they use twigs as a winter food source
(Abrams 1998, Horsley et al. 2003). In
contrast, oak species are highly preferred by
deer in all seasons and continual summer
browsing most likely results in oak seedling
and sapling mortality and limits canopy tree
recruitment (Canham et al. 1994, Abrams
1998).
Despite the differences in land-use history,
the age structure of the maritime forest closely
matches that of the interior forest, including
the maximum ages of tree in plowed versus
unplowed soils. Thus, it appears that the vast
majority of Mashomack oak forests were cut
(in the interior) or developed following agri-
cultural abandonment (maritime forest) in the
1870s time period. In the maritime forest,
black oak, pignut hickory, and chestnut oak
dominated tree recruitment from approxi-
mately 1875 to 1940. Red maple and beech
occur only at low levels, and may be limited by
dense greenbriar cover and oceanic influences
of salt spray, high winds, and sand blasting in
maritime forests. Thus, there is no obvious
developmental pathway leading from oak-
hickory to a later successional beech-maple
type in the maritime forest as seen in the
interior forest. Indeed, black oak and pignut
hickory have found opportunities to recruit
in the maritime forest in recent decades de-
spite pressure from deer browsing and high
shrub cover and may continue to do so in the
future.
The number of young sassafras, black
cherry, and serviceberry in the maritime black
oak forest is remarkable in the face of deer
browsing and dense greenbriar cover. Sassa-
fras and black cherry are even less shade
tolerant and shorter lived than black oak and
pignut hickory and are more likely to die off as
the forest matures and the canopy becomes
more closed (Burns and Honkala 1990). They
are moderately preferred browse species for
white-tailed deer, whereas the shade tolerant
serviceberry is highly preferred (Elias 1980,
Johnson et al. 1995). It is possible that the high
density of greenbriar limits the movement of
deer in the maritime forest to a system of trails
they created (pers. obs.) and therefore pro-
vides protection from browsing of tree regen-
eration away from the trails.
The most prevalent soil types on Masho-
mack are the Montauk sandy loam and
Montauk loamy sand (Warner et al. 1975).
These soils tend to be acidic, droughty and
nutrient poor. Indeed, our soil chemical
analysis of the upper B horizon from the
forest plots supports this description. Relative
to most other soils in the eastern U.S., soil
cations, and pH at Mashomack are low
(Pritchett 1979, David and Lawrence 1996,
Sims and Gartley 1996). However, when
compared to other northern coastal plain
soils, the Mashomack values are quite typical.
For example, pH values ranged from 4.3 to 5.3
for upland oak and pine forests on the coastal
plain of Cape Cod, Massachusetts (Motzkin et
al. 2002). In that study, Ca ranged from 29 to
80 ppm, Mg ranged from 10 to 28 ppm, K
ranged from 8 to 22 ppm, and CEC ranged
from 1 to 13 meq/100 g, similar to values we
report for Mashomack. Comparable values
are also reported for the Pine Barrens soils in
New Jersey and for coastal plain soils in
Delaware (Foreman 1979, Sims and Gartley
1996). Despite low soil fertility at Mashomack,
the trees of most species are growing quite
well, most in the range of 7–10 mm yr21 in
diameter increment (Abrams and Hayes,
unpublished data).
The maritime soil types appear to be
somewhat superior and better suited for
agriculture compared with the coastal interior
forest soils, which contain more sands. Mar-
itime soils containing a plowed horizon are
more fertile and retain more nutrients (higher
CEC) than unplowed soils. This suggests the
possibility that agricultural activities along
2008] ABRAMS AND HAYES: IMPACTS OF LAND-USE HISTORY 49
with livestock grazing further improved the
nutrient content of the maritime soils. Plowed
soils at Mashomack support more of the mesic
white oak and less of the drought-tolerant
black oak than unplowed soils. In central
Massachusetts, plowed soils had similar chem-
istry to unplowed soils, but they supported
forest with higher pitch pine (Pinus rigida
Mill.), white oak, Rubus spp., and birch
(Motzkin et al. 1996). Forests on abandoned
agricultural lands in eastern New York are
dominated by white oak, black oak, and
pignut hickory, and also had a similar nutrient
content to unplowed soils (Glitzenstein et al.
1990). Agricultural soil chemistry did not
differ significantly from primary and second-
ary forests soils in central New York (Flinn et
al. 2005). Thus, the plowed soils at Masho-
mack seem to be somewhat unique among
U.S. studies in that they are more fertile than
unplowed soils. These results are similar to
several European studies in which previous
agricultural lands had higher pH, P, and/or Ca
(Koerner et al. 1997; Verheyen et al. 1999).
Most of the post-agricultural maritime
forest understory is covered in a dense thicket
of greenbriar. High shrub cover is a likely
important contributing factor to the lack of
forest regeneration there (O’Brien et al. 2006).
This in turn probably explains the lower tree
density and species diversity in the maritime
forest, mostly from a lack of beech, red maple,
and dogwood, as compared with the interior
forest. It is interesting to note that the
combination of high deer density and high
cover of a preferred browse species (green-
briar) is unusual for the eastern U.S (Healy
1997). Intensive white-tailed deer browsing
typically leads to either a very sparse forest
understory (like the interior forest) or the
domination by shrub species typically avoided
by deer (e.g., Kalmia and Rhododendron;
Moser et al. 1996). High cover of greenbriar
at Mashomack suggests several different but
not mutually exclusive scenarios involving
deer, including the early history of greenbriar
establishment, limited deer access in dense
thickets and predator satiation.
Smilax represents a super-dominant species
that has the potential to influence a vast array
of ecological processes. High levels of green-
briar also exist in other areas of Long Island,
such as in black oak-vine forests (Greller
1977). Oak and pine coastal plain forests on
Cape Cod Massachusetts include a vegetation
type called oak-briar (Motzkin et al. 2002).
The frequency of greenbriar there is highest in
open sites (63%), but is also high in plowed
(41%), disturbed (23%), and woodlot (36%)
communities. Thus, it appears that the factors
relating to high cover of greenbriar in other
anthropogenic-disturbed maritime environ-
ments of Long Island and Cape Cod are
similar to that on Mashomack. We believe
that most of the differences in forest compo-
sition between the two forest types at Masho-
mack can be attributed to contrasting land-use
history. Indeed, our analysis of soil type and
chemistry on tree species distribution within
and between the two forest types yielded no
significant differences except on plowed versus
unplowed soils within the maritime forest. It is
important to note, however, that differences in
microclimate between the maritime and inte-
rior forest not measured here may explain
some of the compositional variation.
Varying degrees of deer browsing now and
in the future may curtail the recruitment of
most tree species in both forest types, but
particularly in the interior forest where access
is not limited by the dense greenbriar.
Alternatively, greenbriar imposes its own
competitive pressure on tree regeneration in
the maritime forest. We believe that many of
the differences in the overstory and understory
composition, successional pathways, and soil
morphology (Ap horizon) and chemistry
between the two forest types can be attributed
to their contrasting land-use history. Green-
briar thickets formed after agricultural aban-
donment appear to have the ability to
profoundly influence many past, present and
future ecological processes in the maritime
forest. The results of this study contribute to
the rather sparse ecological literature describ-
ing land-use history impacts on plant geogra-
phy, forest dynamics and soils, and in this case
the creation of a super-dominant understory
species.
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