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Plant Communities of the Burden Hill Forest, Salem County, New Jersey
Stevens Heckscher, James F. Thorne, Mike Bertram, and Michael Ward

Northeastern Naturalist, Volume 17, Issue 1 (2010): 49–62

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2010 NORTHEASTERN NATURALIST 17(1):49–62 Plant Communities of the Burden Hill Forest, Salem County, New Jersey Stevens Heckscher1,*, James F. Thorne1, Mike Bertram1, and Michael Ward1 Abstract - The plant community types on three tracts within the Burden Hill Forest, a distinctive outlier of the New Jersey Pine Barrens, are described and classified. While these tracts consist largely of a general pine barrens type, they display a number of significant differences from the main body of the Pine Barrens. These differences include additional forest plant community types previously undescribed for New Jersey, higher heterogeneity of community types and woody plant diversity, and the presence of several unusual or rare species including Castanea pumila (Allegheny Chinquapin). Introduction The Burden Hill Forest, approximately 60 km2 (23 mi2) in total area, is located in Alloway, Quinton, and Lower Alloway townships in Salem County, southwestern New Jersey (Fig. 1). Collins and Anderson (1994) place the forest within the outer Coastal Plain, and Gordon and Arsenault (2006) do not regard it as a Pine Barrens outlier. Following Forman (1979) and Woods et al. (2007a, b), we consider this forest to be an outlier of the New Jersey Pine Barrens surrounded by Inner Coastal Plain. The low population density of Salem County has left the forest far less fragmented than the Pine Barrens outlier near Spotswood (Middlesex County). Its location outside the Pinelands Reserve offers it none of the legal protections of the central Pine Barrens, and residential development and roads continue to fragment the forest. The New Jersey Conservation Foundation (NJCF) highlighted the Burden Hill Forest as its single largest “high priority habitat” and a top preservation priority for the Delaware Estuary (Honigfeld 1997). In 1999, the Natural Lands Trust of Philadelphia (NLT) joined forces with NJCF and the New Jersey Green Acres Program to coordinate purchases in the forest. To date, 266 ha (657 acres) have been purchased, and an additional 53.4 ha (132 acres) have been preserved through easements. Our objectives were to describe and classify the plant communities of the Burden Hill Forest, one of New Jersey’s most biologically rich sites, eminently worth describing and preserving. Site Description Burden Hill Forest possesses similar soils to those of the Pine Barrens and is underlain by the same Cohansey and Kirkwood groundwater aquifers, but 1Natural Lands Trust, 1031 Palmers Mill Road, Media, PA 19063. *Corresponding author - sheckscher103@comcast.net. 50 Northeastern Naturalist Vol. 17, No. 1 is separated from the central pinelands by twenty miles of more fertile coastal plain soils. According to the Salem County Soil Survey (USDA 1969), the dominant soil association for Burden Hill is the Sassafras-Evesboro-Downer Association, which supports mostly very droughty and nutrient-poor soils. The Soil Survey notes that areas abandoned from agriculture tend to grow up in pines. Burden Hill is the largest forest in Salem County. Robichaud and Buell (1973) describe this forest as mostly a type of mixed oak forest, similar to the oak-pine forests of the Pine Barrens. Its wetlands consist of seeps, small streams, vernal ponds, and a permanent dammed pond. These contain extensive stands of Helonias bullata L. (Swamp Pink), a federally listed plant, as well as the state-protected Listera australis Lindl. (Southern Twayblade). Castanea pumila (L.) P. Mill. (Allegheny Chinquapin), a state-endangered species, is scattered throughout the forested upland areas (S. Heckscher, pers. observ.). The forest is home to two state-listed birds known for their affinities to large tracts of mature, unbroken forest: Buteo lineatus Gmelin (Red-shouldered Hawk) and Strix varia Barton (Barred Owl). F i g u r e 1 . Location of study area in Burden Hill Forest. 2010 S. Heckscher, J.F. Thorne, M. Bertram, and M. Ward 51 We studied three tracts of the Burden Hill Forest recently acquired and now managed by the NLT: the Alloway Tract (62.9 ha [155.4 acres]), the Cool Run Tract (84.8 ha [209.5 acres]), and the Route 49 Tract (34.7 ha [85.7 acres]) (Fig. 1). Using the results of this study, NLT has produced a management plan for its holdings in this forest (Natural Lands Trust 2004). Methods Botanical nomenclature follows Kartesz (1994). Woody plants with a diameter at breast height (DBH) greater than or equal to 10 cm were classified as trees, and woody plants with a DBH ranging from 1 cm to 10 cm were classified as shrubs. Shrub stems were counted individually when they were separate and distinguishable at ground level. Sampling design Our method for sampling the vegetation was a stratified, iterative design similar to that used by Pennsylvania Bureau of Forestry (2001). A color infrared aerial photograph of the entire Burden Hill forest was overlaid onto a GIS base map of the three study tracts (ESRI n.d., version 9.1). Polygons were drawn on the GIS map of each tract, each bounding an area more or less uniform in color and texture and considered to represent a distinct forest community type. On this map, we superimposed a square, north–south, east–west grid system, creating 0.4-ha quadrats. We randomly selected sampling quadrats until the sampling area totaled a minimum of 10% of the total area of each polygon. A few polygons were too small or too narrow to fully contain quadrats, and were not included in the analyses. These were examined in the field, and their community classifications were determined by direct inspection. Data collection in the field We placed two concentric, circular sampling plots (20-m and 5-m diameters) at the center of each randomly selected quadrat. We counted and recorded the DBH of each tree within the larger plots and tallied the number of shrub stems within the smaller plots. For each tree species in each plot, we calculated relative density (number of stems for the species / total number of tree stems), relative dominance (total basal area for the species / total basal area for all tree species), and importance value (100 * [relative density + relative dominance] / 2). For each shrub species in each plot, we calculated relative density (number of stems for the species / total number of shrub stems) and importance value (100 * relative density). Analyses We used multivariate analyses on four data sets for the purposes of delineation and naming of community types: (1) on tree data from each of the three tracts, with each tract examined separately; (2) on tree data from all three tracts combined into a single data set; (3) on shrub data from each of the three tracts separately; and (4) on shrub data from all three tracts 52 Northeastern Naturalist Vol. 17, No. 1 combined into a single data set. We used TWINSPAN to detect patterns in the data and to help us to name and describe community types. To search for additional patterns in the data, we also ran on each of the data sets (2) and (4) a detrended correspondence analysis (DECORANA), principal components analysis, and two cluster analyses using Euclidean distances, the first with separation by distances between centroids, and the second by distances between nearest neighbors. The software used for these programs was PCORD (McCune and Mefford 1997). Using the results of the TWINSPAN runs, community types consisting of categories subdivided into community elements were named, described according to dominant and other important species present, and mapped. We used the polygons mapped earlier as guidelines wherever possible. Several additional forays were then made into the field, ensuring that each community type on each tract was carefully inspected at least once, and amendments to the maps were made accordingly. Where possible, community elements and categories that we identified were then cross-referenced (crosswalked) to plant community classifications in the second iteration of the New Jersey Vegetation Classification (NJVC) (Breden et al. 2001). We made note of significant differences between our results and those of NJVC, and these are noted in the discussion section below. Results We assessed and mapped the plant community types for the Alloway Tract (Fig. 2), the Cool Run Tract (Fig. 3), and the Route 49 Tract (Fig. 4) in the Burden Hill Forest. Detailed descriptions of each of these community types follows. Acidic soils Pitch Pine forest. On the Burden Hill tract, this category consists only of a small stand of Pinus rigida P. Mill. (Pitch Pine) of questionable etiology— probably planted years ago, or a successional pine community. It is poorly represented here, and for these reasons it is not divided into community elements. Moreover, on the Route 49 Site there is a recently disturbed area now being colonized by a stand of Pinus rigida seedlings and saplings, marked “early Pitch Pine regeneration” (EP) on Figure 4. Broadleaf or broadleaf-needleleaf forest with a heath-shrub understory. Community elements in this category are those with a broadleaf, or broadleaf and needleleaf, more or less closed, canopy over a heath-shrub understory. Oaks, especially Quercus alba L. (White Oak), predominate among the broadleaf species, and Pinus rigida is the most important needleleaf tree. The colonial species Gaylussacia baccata (Wangenh.) K. Koch (Black Huckleberry) is generally dominant in the shrub layer, and provides a fairly good indicator species for this category. Community elements are as follows: 2010 S. Heckscher, J.F. Thorne, M. Bertram, and M. Ward 53 Xeric-mesic oak: This xeric-mesic hardwood community is dominated by Sassafras albidum (Nutt.) Nees (Sassafras) and the following oaks in various combinations: Quercus alba, Q. coccinea Muenchh. (Scarlet Oak), Q. falcata Michx. (Southern Red Oak), and Q. velutina Lam. (Black Oak). Castanea pumila is sometimes present, and Carya glabra (P. Mill.) Sweet (Pignut Hickory) is scattered throughout. Pinus rigida is absent, although P. virginiana P. Mill. (Scrub Pine) may be present as an oldfield relic. The shrub layer appears to be extremely depauperate, with the only species recorded in it during our data collection being Gaylussacia baccata. Oak-pine: In this xeric-mesic community element, the following oaks in varying combinations co-dominate: Quercus alba, Q. falcata, Q. coccinea, Q. velutina, and Q. prinus L. (Chestnut Oak). Pinus rigida is always present, sometimes as a co-dominant, and was regarded by us as an indicator species separating this community element from the xeric-mesic oak community element. Sassafras albidum is present and often abundant. Other hardwoods sometimes present include Acer rubrum L. (Red Maple), Ilex opaca Ait. (American Holly), Liquidambar styraciflua L. (Sweet Gum), Nyssa sylvatica Marsh. (Black Gum), and Prunus serotina Ehrh. (Black Cherry). Castanea Figure 2. Alloway Site: woody plant communities as determined by this study. Small circles denote sampling points. Note that community types are often not sharply delineated; boundaries between them are usually more or less gradual. AC = Atlantic White Cedar Swamp, DPP = disturbed Pitch Pine and Black Cherry, EP = early Pitch Pine regeneration, MH = mixed hardwoods, MHH = mesic-hydric hardwoods with lowland pitch pine, MHL = mature mixed hardwoods with Mountain Laurel shrub layer, MV = mid-successional oldfield with Virginia Pine, OF = open field, OH = oak-American Holly, OL = oak-Mountain Laurel, OP = oak-pine, OS = open shrubland with Water Willow, PP = Pitch Pine forest, PRB = Red Maple-Black Gum palustrine forest, PRP = permanent pond, RMR = Red Maple-Black Gum-Sweetbay Magnolia riparian forest, SP = seasonal pond, and XM = xeric-mesic oak. 54 Northeastern Naturalist Vol. 17, No. 1 pumila is present and varies from sparse to abundant. Stump sprouts of C. dentata (Marsh.) Borkh. (American Chestnut) were found in two quadrats. Pinus echinata P. Mill. (Shortleaf Pine) is present but sparse, while Pinus virginiana and Juniperus virginiana L. (Red Cedar) are often present, probably as oldfield relicts. A few hickories, i.e., Carya glabra and C. alba (L.) Nutt. ex Ell. (SY = C. tomentosa (Lam. ex Poir.) Nutt.) (Mockernut Hickory), are sometimes present. In the shrub-layer, Smilax glauca Walt. (Glaucous Greenbriar) and S. rotundifolia L. (Greenbriar) are sparse, along with the usually abundant Gaylussacia baccata and Vaccinium pallidum Ait. (Hillside Blueberry). Oak-American Holly: Oaks—Quercus prinus, Q. falcata, and Q. coccinea— dominate. Ilex opaca is likely the most abundant element of the subcanopy, and Acer rubrum is present in small numbers. The shrub layer, dominated by Gaylussacia baccata, is species-poor, but may contain Kalmia latifolia L. (Mountain Laurel). Oak-Mountain Laurel: Oaks—Quercus coccinea, Q. alba, Q. falcata, and Q. prinus—co-dominate with Sassafras albidum. Pinus rigida and Figure 3. Cool Run Site: woody plant communities as determined by this study. Small circles denote sampling points. Note that community types are often not sharply delineated; boundaries between them are usually more or less gradual. See Figure 2 for community abbreviations. 2010 S. Heckscher, J.F. Thorne, M. Bertram, and M. Ward 55 P. virginiana are present but variable, as is Castanea pumila. The shrub layer consists of Gaylussacia baccata with Kalmia latifolia, which may be very dense in places where little grows under it, and Vaccinium pallidum. Disturbed Pitch Pine and Black Cherry: In this disturbed element, Pinus rigida and Prunus serotina are most abundant. Other hardwoods of some importance include (in order of decreasing abundance) Cornus florida L. (Flowering Dogwood), Sassafras albidum, and Castanea pumila. Oaks are sparse. Juniperus virginiana, an oldfield relic, is present. In the shrub layer, Kalmia latifolia and Gaylussacia baccata are present and may be abundant. This community type occurs only in a small polygon of the Cool Run tract that has been heavily disturbed, so this description must be regarded as provisional. Rich soils Rich broadleaf forest (“mixed oak”). This category appears to be a variant of the "mixed oak forest" of Collins and Anderson (1994). It is Figure 4. Route 49 Site: Woody plant communities as determined by this study. Small circles denote sampling points. Note that community types are often not sharply delineated; boundaries between them are usually more or less gradual. See Figure 2 for community abbreviations. 56 Northeastern Naturalist Vol. 17, No. 1 characterized by a mixture of oaks, with other hardwoods, and little or no pine. Community elements are as follows: Mature mixed hardwoods with a Mountain Laurel shrub layer: This community element consists of the most mature hardwood stand encountered in this study. Oaks include at least Quercus falcata, Q. coccinea, and Q. alba. Stump sprouts of Castanea dentata are present. Other hardwoods include Carya alba (SY = C. tomentosa), C. glabra, Fagus grandifolia Ehrh. (American Beech), Cornus florida, Sassafras albidum, and Ilex opaca. The understory is unevenly dominated by Kalmia latifolia. This type is quite possibly a more mature version of the oak-Mountain Laurel element, as described above. Mixed hardwoods: This community element differs from the last in that here Kalmia latifolia is absent. It contains a mixture of oaks including Quercus falcata, Q. coccinea, and Q. alba. Other hardwoods may include any of the following: Carya alba (SY = C. tomentosa), C. glabra, Fagus grandifolia, Cornus florida, Sassafras albidum, and Ilex opaca. Scattered pines and Castanea dentata stump sprouts may occasionally be present. Hydric soils Red Maple-Black Gum riparian or palustrine forest. This category consists of riparian or palustrine forests dominated by Acer rubrum, with Nyssa sylvatica present but often sparse. Gaylussacia species, Vaccinium species, Clethra alnifolia L. (Sweet Pepperbush), and Rhododendron viscosum (L.) Torr. (Swamp Azalea) are often present in the shrub layer. Community elements are as follows: Red Maple-Black Gum-Sweetbay Magnolia riparian forest: Acer rubrum is dominant. Nyssa sylvatica and Magnolia virginiana L. (Sweetbay Magnolia) are present but may be sparse. Clethra alnifolia, Gaylussacia frondosa (L.) Torr. & Gray ex Torr. (Dangleberry), and Rhododendron viscosum are found in the shrub layer. While not reported in our data for this element, Vaccinium corymbosum L. (Highbush Blueberry) has been seen locally and should be looked for here, where it is probably quite common. Also to be looked for here are Ilex verticillata (L.) Gray (Winterberry), Leucothoe racemosa (L.) Gray (Deciduous Swamp Fetterbush), and Ilex glabra (L.) Gray (Inkberry). Red Maple-Black Gum palustrine forest: Acer rubrum is dominant. Nyssa sylvatica is present but may be sparse. The shrub layer contains Gaylussacia baccata, Vaccinium pallidum, and V. corymbosum. The single, small polygon containing this community element, on the Route 49 tract, has been strongly modified by recent disturbance, so this description must be regarded as provisional. Hydric broadleaf-needleleaf forest. Description for the only community element, below. Mesic-hydric hardwoods with lowland Pitch Pine: Of importance are Nyssa sylvatica, Ilex opaca, and Pinus rigida. Small numbers of Acer rubrum 2010 S. Heckscher, J.F. Thorne, M. Bertram, and M. Ward 57 are present; this paucity, combined with the abundance of Pinus rigida, distinguish this community element from the Red Maple-Black Gum-Sweetbay Magnolia riparian forest element, where A. rubrum is dominant. Castanea pumila is sometimes present. Facultative wetland hardwoods include Liriodendron tulipifera L. (Tulip Tree), Quercus falcata, and Liquidambar styraciflua. Wetland indicators Quercus bicolor Willd. (Swamp White Oak) and Magnolia virginiana are present but in small numbers. Vaccinium corymbosum, Gaylussacia baccata, G. frondosa, Clethra alnifolia, Leucothoe racemosa, and Lyonia ligustrina (L.) DC (Maleberry) are often abundant in the shrub layer. Rhododendron viscosum is not present in our data for this community element, although according to NJVC it probably occurs here. Atlantic White Cedar swamp. This is not divided into community elements. It consists of swamp forest strongly dominated by Chamaecyparis thyoides (L.) B.S.P. (Atlantic White Cedar). Miscellaneous Mid-successional oldfield with Virginia Pine. This type is not divided into community elements. It is dominated by Pinus virginiana, apparently succeeding to hardwoods. Open shrubland with Water Willow. This type is not divided into community elements. It consists of hydric shrubland with a high density of Decodon verticillatus (L.) Ell. (Water Willow). Discussion In this study, we have made a first attempt at naming, describing, and mapping the woody plant communities on three tracts in the Burden Hill Forest, classifying the communities into categories subdivided into community elements. Because we are working at a far finer scale, our names deliberately reflect a finer detail than those of Breden et al. (2001). Figures 2–4 show the locations of our community types. The Burden Hill Forest differs from the main New Jersey Pine Barrens in at least two respects. First, the forest appears more heterogeneous, displaying a rich mosaic of different plant community types. For example, the oak-dominated communities have higher species diversity of oaks and other woody plants, including the rare Castanea pumila, and a greater abundance of Ilex opaca in places in the understory. Secondly, the C. pumila, while quite common at Burden Hill, is scarcely found elsewhere in the state. One similarity of the Burden Hill Forest to the main New Jersey Pine Barrens is important. Our second category, broadleaf or broadleaf-needleleaf forest with a heath-shrub understory, consists of mixed hardwoods, with or without Pitch Pine, over heath shrubs, mainly the colonial and clonal Gaylussacia baccata (Black Huckleberry). This composition suggests strongly that this category belongs to the generalized, fire-adapted pine-oak heath 58 Northeastern Naturalist Vol. 17, No. 1 type (Whittaker 1979) common not only in the New Jersey Pine Barrens, but also on acidic ridgetops in the Piedmont and Ridge and Valley provinces, and elsewhere. According to Little (1979), fire has been a significant ecological factor in shaping community types in large parts of the Burden Hill area, as is true with the main Pine Barrens, but there is some controversy over this point, and the shrub or small tree Quercus ilicifolia Wangenh. (Bear Oak) common in openings of this forest type in the main Pine Barrens, is nearly or completely absent on our Burden Hill project area. It is also instructive to compare our findings to those of Olsson (1979), which covered the “central fifth of the New Jersey Pine Barrens.” Our second category, broadleaf or broadleaf-needleleaf forest with a heath-shrub understory, corresponds most closely to Olsson’s pine-oak vegetation type. His Entity A1, Pinus rigida-Quercus ilicifolia, differs from our second category in its abundance of Q. ilicifolia in the understory. His Entity A3, Quercus alba-Q. prinus-Q. velutina, is similar to our second category except that in our study area, Q. ilicifolia appears to be nearly or completely absent, Q. falcata is present, and Q. prinus is comparatively less abundant. Although Ilex opaca occurs at least sporadically in poorer-drained sites throughout much of the New Jersey Pine Barrens, nothing similar to our oak-American Holly community element appears in Olsson’s (1979) classification or that of NJVC. While this type apparently does not occur in the main body of the Pine Barrens, a similar community type does occur in the Glades Region of New Jersey’s Cumberland County near Fortescue (Heckscher 1994). This region lies near the Delaware Bayshore about 25 miles to the southeast of the Burden Hill Forest. More or less dense stands of Ilex opaca are probably widely distributed in Cumberland and Cape May counties, and also on New Jersey’s Inner Coastal Plain (anonymous reviewer, pers. comm.). See Collins and Anderson (1994) for comments on American Holly in southern New Jersey. Likely factors influencing the distribution of I. opaca and other species at Burden Hill include proximity to the Inner Coastal Plain, where I. opaca is more common, as well as soils, geology, and a more southerly climate than that of the main Pine Barrens. Gordon and Arsenault (2006) point out that, at Burden Hill, needleleaf evergreen species such as Pinus rigida and P. echinata “occupy gaps or scars of exposed mineral soil created by traditional land uses, and other smallscale forest disturbances.” They attribute to the proximity of the rich Inner Coastal Plain of south Jersey the presence at Burden Hill of at least seven deciduous hardwood tree species. As a contribution towards the ongoing work of classification of plant communities in New Jersey, in Table 1 we have cross-referenced (crosswalked) our groupings (categories and community elements) to NJVC; i.e., we have indicated the alliances and plant associations of NJVC into which our groupings most nearly fit. Some of our groupings do not have clear crosswalks to the present iteration of NJVC. We list and discuss these difficulties 2010 S. Heckscher, J.F. Thorne, M. Bertram, and M. Ward 59 Table 1. Cross- references (crosswalks) for the plant community elements found by us at the Burden Hill Forest, NJ, to the corresponding alliances and plant associations reported in the New Jersey Vegetation Classification (NJVC) (Breden et al. 2001).1 Burden Hill element NJVC alliance NJVC plant association Xeric-mesic oak I.B.2.N.a.100: Quercus velutina-Quercus alba- Quercus coccinea–Quercus velutina/ (Quercus coccinea) forest Sassafras albidum/Vaccinium pallidum forest Oak-pine I.C.3.N.a.35: Pinus (rigida, echinata)-Quercus Ambiguous; see text coccinea forest; a poor fit; see text Oak-American Holly Unknown Oak-Mountain Laurel I.B.2.N.a.100: Quercus velutina-Quercus alba- Quercus velutina-Quercus coccinea- (Quercus coccinea) forest Quercus montana (SY = Q. prinus)/ Kalmia latifolia forest Disturbed Pitch Pine and Black Cherry Unknown Mature mixed hardwoods with a Mountain Laurel shrub layer Belongs to formation I.B.2.N.a: lowland or Ambiguous; see text submontane cold-deciduous forest; alliance ambiguous, but see text Mixed hardwoods Possibly I.B.2.N.a.31: Quercus falcata forest, Unknown a poor fit; see text Red Maple-Black Gum-Sweetbay Magnolia riparian forest I.B.2.N.g.2: Acer rubrum-Nyssa sylvatica Acer rubrum-Nyssa sylvatica/ saturated forest Rhododendron viscosum-Clethra alnifolia forest Red Maple-Black Gum palustrine forest I.B.2.N.g.2: Acer rubrum-Nyssa sylvatica Acer rubrum-Nyssa sylvatica-Magnolia saturated forest virginiana forest Mesic-hydric hardwoods with lowland Pitch Pine I.C.3.N.d.300: Pinus rigida-Acer rubrum Pinus rigida-Acer rubrum/Rhododendron saturated forest viscosum forest Atlantic White Cedar swamp I.A.8.N.g.2: Chamaecyparis thyoides Chamaecyparis thyoides/Ilex glabra forest saturated forest Mid-successional oldfield with Virginia Pine Possibly I.C.3.N.a.27: Pinus virginiana-Quercus Unknown (alba, stellata, falcata, velutina) forest; see text Open shrubland with Water Willow Unknown 1Because it is small, fragmentary, and probably a remnant of a planted area, our element Pitch Pine forest is not shown in this table (see text). 60 Northeastern Naturalist Vol. 17, No. 1 next, and we suggest that they may reveal gaps in the present iteration of NJVC, where further study is needed. Oak-pine: This community element fits uneasily into NJVC’s alliance I.C.3.N.a.35, PINUS (RIGIDA, ECHINATA)-QUERCUS COCCINEA FOREST, corresponding poorly to the descriptions of both its NJVC associations, as follows: Pinus (rigida, echinata)-Quercus coccinea/Ilex opaca forest (our oak-pine element is probably on drier soil). Pinus rigida-Quercus coccinea/Vaccinium pallidum-(Morella [=Myrica] pensylvanica Loisel.) forest. Oak-American Holly: Because pines are absent from our data on this community element on Burden Hill, and also apparently from its polygon as seen on the infrared aerial photograph, we cannot crosswalk this element to NJVC’s PINUS (RIGIDA, ECHINATA)-QUERCUS COCCINEA / ILEX OPACA FOREST (under I.C.3.N.a.35). Indeed, we cannot find any alliance or association in NJVC to which this community element can be crosswalked. Further study is needed, but see the references to American Holly in Collins and Anderson (1994), and our discussion above. Disturbed Pitch Pine and Black Cherry: We can find no fit in NJVC for this community type, which appears to be the result of recent disturbance. Mature mixed hardwoods with a Mountain Laurel shrub layer: While this element clearly belongs to formation I.B.2.N.a, lowland or submontane cold-deciduous forest, its understorey dominance by Kalmia latifolia renders assignment to a current NJVC alliance difficult or impossible. This type may be a more mature successional stage of oak-Mountain Laurel (q.v.), in which case it could fit into alliance I.B.2.N.a.100, QUERCUS VELUTINA-QUERCUS ALBA-(QUERCUS COCCINEA) FOREST and association Quercus velutina- Quercus coccinea-Quercus montana forest. We suggest further study. Mixed hardwoods: The NJVC alliance that most nearly corresponds to this Burden Hill element is I.B.2.N.a.31, QUERCUS FALCATA FOREST, but the fit is poor and no appropriate association can be found in the current iteration of NJVC; indeed, the latter document indicates the need for further study to assess the distribution of this alliance. Mid-successional oldfield with Virginia Pine: The alliance I.C.3.N.a.27, to which this community type may crosswalk, apparently does not contain midsuccessional communities. To the best of our knowledge, no mid-successional oldfield communities dominated by Pinus virginiana are presently covered in NJVC, but such communities are discussed in Collins and Anderson (1994). Open shrubland with Water Willow: We could find no alliance in NJVC into which this Burden Hill community element can fit. We suggest further study on this element at Burden Hill where it occupies only a small area, and elsewhere. 2010 S. Heckscher, J.F. Thorne, M. Bertram, and M. Ward 61 This paper is a preliminary study of portions of the Burden Hill Forest. As such, we believe, it adds new content to our knowledge and understanding of plant community types in New Jersey. We hope that our work will contribute towards the next iteration of NJVC, and that, as additional portions of this valuable tract are protected, further ecological studies covering more of the forest will be carried out. Acknowledgments During the course of this study, we have received suggestions and other forms of assistance from a number of individuals, to whom we gratefully extend our thanks. These include Ann Rhoads, Roger Latham, Steve Eisenhauer, Joe Arsenault, Ted Gordon, Kay Baker, Andy Selleman, Glen Mittelhauser, and three anonymous reviewers. Rebecca McGuire and Mike McGeehin meticulously prepared the maps on a GIS system. This research was supported in part by generous grants to the Natural Lands Trust by the Beneficia Foundation, the Geraldine R. 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