Northeastern Naturalist Vol. 21, No. 1 E.W.B. Russell Southgate and J.E. Thompson 2014 NENHC-35 2014 NORTHEASTERN NATURALIST 21(1):NENHC-35–NENHC-50 Secondary Forest Succession in a Post-agricultural Landscape in the Hudson Valley, New York Emily W.B. Russell Southgate1,* and John E. Thompson2 Abstract - Quercus spp. (oaks) were the most abundant trees in the pre-colonial forests of the Hudson Valley. Over the last century, secondary forests have replaced many of the agricultural fields that were established after these forests were cut. Mohonk Preserve’s Foothills, New Paltz, NY, includes secondary forest stands ranging in age from about 30 to 100 y. Stands on similar substrates and soils differ not only in age, but also in the factors that influenced forest development at and since field abandonment such as seed sources and herbivory. This study analyzed the composition of 8 stands of various ages to evaluate the possible importance of site-specific differences in these factors. Oaks dominate only one stand, and Acer saccharum (Sugar Maple) is the major sapling species in all well-drained stands. We attribute differences in stand composition, particularly the lack of oaks and the prevalence of Sugar Maple, mainly to differences in drainage, seed sources, and extent of deer browse. Introduction For at least six millennia, Quercus spp. (oak) forests have dominated the vegetation of the northeastern United States (Bernabo and Webb 1977, Maenza- Gmelch 1997, Menking et al. 2010, Whitney 1994, Williams et al. 2004), yet today most oak forests in the region are not regenerating well (Schuster 2011). This lack of regeneration has raised questions concerning the factors that maintained oak dominance in this region for many millennia and how they have changed in the last few centuries (Foster et al. 1998, Loftis and McGee 1993). In this study, we characterize the structure and composition of eight forest stands in an agricultural landscape in eastern New York and consider the importance of their land-use history on their current species composition. Our objectives were to 1) determine current tree and sapling composition of these stands and to compare these with 18th-century forest composition; 2) compare the stands in relation to drainage, slope, and date of abandonment; and 3) consider the likely influence of past and present herbivory, seed sources, fire, and post-abandonment logging on current tree and sapling composition. In eastern New York and throughout the eastern US, much of the land previously used for agriculture has reverted to forest over the last century. Most forests in the northeastern US are young; more than half of forest stands are less than 50 y old, and less than 2% are over 125 y old (Smith and Darr 2002). The extent of oak/Carya spp. (hickory) forest was about 20 million ha from 1977 to 2002, while the extent of Acer spp. (maple)/Fagus grandifolia Ehrh. (American Beech)/Betula 1Department of Biology, Hood College, Frederick, MD 21701. 2Mohonk Preserve, New Paltz, NY 12561. *Corresponding author - ewbsouthgate@gmail.com. Manuscript Editor: Donald Leopold Northeastern Naturalist NENHC-36 E.W.B. Russell Southgate and J.E. Thompson 2014 Vol. 21, No. 1 spp. (birch) forest increased from 16 to 22 million ha during the same period (Smith and Darr 2002). Because this process of forest re-growth is continuous, there may be forest fragments that range in age from a century to only a few decades old within small areas. Using historical documents, field observations, and historic aerial photographs, one can infer approximate abandonment dates for agricultural fields and compare the structure and composition of forests on similar soils with similar climate but different dates of abandonment. Because factors affecting succession change over time, forests of different ages differ also in conditions such as herbivory and regeneration at various stages of their development. These historically varying factors may play an important part in determining forest stand composition. Here we consider changes over time in fire, herbivory, changing seed sources, and post-abandonment logging as factors that influence stand composition. Fire has been studied as a factor both in oak establishment (McEwan et al. 2007) and in regeneration within established oak forests (Arthur et al. 2012, Brose et al. 2001, Loftis and McGee 1994). Fire may remove fire-sensitive species that compete with oaks, such as maples and beech, resulting in the creation of gaps in the canopy and accompanying higher light intensities on the forest floor. Odocoileus virginianus Zimmerman (White-tailed Deer) and other herbivores may influence woody species recruitment and regeneration by selective browsing. Browsing on acorns and seedlings can severely limit oak regeneration (Côté et al. 2004, Marquis et al. 1976, Wakeland and Swihart 2009). Oaks are masting species that sporadically produce large numbers of acorns, in contrast with other species, such as Acer saccharum Marshall (Sugar Maple), which exhibit more consistent seed production. Selective logging of some species, such as Quercus alba L. (White Oak ), may remove them as seed sources, leaving others such, as Sugar Maple, to increase their proportional input of seeds. Both selective and clear-cut logging may occur at any stage of secondary succession and affect the trajectory of forest development and seed abundance. Field Site Description This project was carried out in the Mohonk Preserve Foothills (Fig. 1), New Paltz, NY. Soils range from excessively well-drained in areas close to the ridge, to somewhat poorly drained in the east (Smiley and Thompson 2012). Slopes range from >15% to almost level (Smiley and Thompson 2012). Most of the area is underlain by Martinsburg Shale, though glacial till with abundant conglomerate is found in some steep areas to the west (Smiley and Thompson 2012). The climate is temperate, with cold winters (monthly average of about -4 °C) and warm summers (monthly average of about 21 °C), with 122 cm of rainfall and 150 cm snowfall (averages calculated based on weather records from 1896–2000; Daniel Smiley Research Center 2012). Mixed farming in the area has continued into the 21st century; today about half of the land is still in agriculture. The remainder, however, has reverted to forest or thick brush. Our study sites were forest stands that had developed on abandoned agricultural land, as indicated by the presence of Juniperus virginiana L. (Eastern Northeastern Naturalist Vol. 21, No. 1 E.W.B. Russell Southgate and J.E. Thompson 2014 NENHC-37 Redcedar ) stems on the forest floor or still standing (Burns and Honkala 1990), by photographic evidence from the mid-20th century, and/or by other historical records. Locations of stands are given in Fig. 1, and characteristics of the stands are presented in Table 1. Methods We searched historical documents at Mohonk Mountain House, Mohonk Preserve, the Elting Memorial Library, and the Huguenot Historical Society (all in New Paltz, NY), and the New York State Archives, Albany, NY for indications of past vegetation, patterns of field abandonment, and evidence of past fire, herbivory, Figure 1. Study area. Table 1. Characteristics of forest stands. 1946 conditions Field Stand Size Edge Name Slope (°) Substrate Drainage (ha) Trees Forested Gateway 0–3 Shale Well 4.5 No Yes Hasbrouck 0–3 Shale Somewhat poorly 4 Yes Yes North of Pine Farm 8–15 Glacial till Well-excessively well 9.5 Yes Yes Above Brook Farm 8–15 Shale Well-excessively well 4.5 Yes Yes P. DuBois 8–15 Shale Well-excessively well 16.5 Yes No Ridgelands >15 Glacial till Well-excessively well 2 Yes No Gateway wet 0–3 Shale Somewhat poorly 4 No No Between Pine and Brook 0–3 Shale Somewhat poorly 5 Yes No Northeastern Naturalist NENHC-38 E.W.B. Russell Southgate and J.E. Thompson 2014 Vol. 21, No. 1 seed sources, and logging. This region was surveyed in the 18th century using metes and bounds survey methods, in which lines were surveyed from point to point. Points were occasionally marked by tree blazes, and surveyors recorded the species of these witness trees. The data that we derived from the old surveys are very diffuse, with at most a few trees for every several hundred hectares, but taken together they provide strong evidence of past species composition (Russell 1997). We sampled tree and sapling composition using the point-centered quarter method (Cottam and Curtis 1956). Depending on the shape of the stand, we laid out 2–5 sampling lines 25 m apart and sampling points 25 m apart along each line. At each point, we measured the distance to the nearest sapling (>2 m tall, ≤5 cm diameter at breast height [DBH]) and the nearest tree (>5 cm DBH) in each quadrant, identified them to species, and recorded the DBH. We sampled at 25 points in each stand, for a total of 100 trees, except for Above Brook Farm where, after sampling 15 points and finding that >80% of saplings and trees were Sugar Maple, we ended our count. We also recorded qualitative observations including the occurrence of large open-grown trees (those having large branches low on the trunk) near the sampling lines or along the forest edges that may have served as seed sources, and dead and/ or fallen Eastern Redcedar stems, which indicated that the stand had developed on abandoned agricultural field. Nomenclature follows the USDA PLANTS Database (http://plants.usda.gov/java/). We estimated the apparent age of each stand by analyzing 1946, 1964, and 1987 aerial photos (Daniel Smiley Research Center Library, New Paltz, NY) and local scenic photographs. In many cases, photographs taken of the same site over time allowed us to observe the gradual disappearance of field edges in some of the stands, and the prominence of large trees on the field edges before and during forest regeneration. We developed descriptive statistics including relative density of saplings and trees by species, number of saplings and trees/ha, and average tree diameter. Results Pre-colonial vegetation White Oak and Quercus velutina Lam. (Black Oak) dominated the small sample of witness trees we found for the study area (36 trees), a pattern also reflected in larger regional samples (Russell 2001, Whitney 1994). A qualitative description of a parcel of land for sale in 1794 characterized the forest composition as White Oak, Black Oak and Quercus rubra L. (Red Oak) with some Castanea dentata (Marshall) Borkh. (American Chestnut) and hickory (Box 9, Folder 41; Cockburn Field Notes [≈1755–1884]). Some other taxa listed in the historical surveys were Nyssa sylvatica Walter (Black Gum), Fraxinus spp. (ash), and Tsuga canadensis (L.) Carrière (Eastern Hemlock). Several swamps were described as Fraxinus nigra Marshall (Black Ash) or F. americana L. (White Ash) swamps (Box 9, Folders 39, 41; Cockburn Field Notes [≈1755–1884]) . Land clearing began in the early 18th century, and most of the land in the study area was cleared for agricultural fields of various sorts over the next 100 years (Federal Agricultural Census Records 1850–1880). There is some indication of Northeastern Naturalist Vol. 21, No. 1 E.W.B. Russell Southgate and J.E. Thompson 2014 NENHC-39 woodlots in the 1880 Federal Agricultural Census returns, but the locations of these are difficult to determine accurately. Forest tree composition Our sites had an average of 665 trees/ha (Table 2), a value higher than the average of 410 trees/ha reported for New York in 2007. This difference is likely due primarily to our DBH threshold of ≥5 cm for trees, rather than 12.5 cm as used to calculate the state average (US Forest Service 2007). This difference also accounted for the very low numbers of saplings/ha that we calculated for our sites. We chose the smaller DBH value to capture information regarding regeneration in these stands. The average tree DBH from our study was 21 cm, a value similar to the state average of 22 cm. White Oak dominates only one of the forest stands we studied, Gateway Woods (Fig. 2). This stand is on well-drained soil on flat terrain and it was clear-cut in about 1882, when “much fine timber” was harvested (Smiley 1941). The lack of multiple-stemmed trees at our study site suggests that the current trees originated from seed rather than as sprouts. Tree cores confirm that the large White Oaks are approximately 100 y old (Carol Rietsma, State University of New York, New Paltz, NY, pers. comm.). The large number of stems/ha in this, the oldest, stand, is most likely the consequence of the large number of understory Ostrya virginiana (Mill.) K. Koch (Hophornbeam). There are also two much smaller White Oak stands with trees approximately the same size in the area below the P. DuBois Woods site, on some elevated ground just west of Humpo Marsh. The larger of these is evident on the 1946 aerial photo. It thus appears that these stands were established by around 1900, because they were well developed by 1946. We observed no evidence of fire at these sites, and it seems unlikely that they have burned. The lack of slope also suggests that these stands have experienced less erosion than those growing on steeper sites. All three stands have some dead Eastern Redcedar logs on the forest floor, indicating prior clearing or forestry operations. These are the only sites where oak was dominant in the >20-cm DBH size-class. Historical photographs also show that Hasbrouck Woods was the only other stand that was forested in 1946 (Fig. 3). In the 1946 aerial photo, the forest at Hasbrouck Woods appears less dense than the forest at Gateway Woods, and has Table 2. Tree measurements. For the purposes of our analysis, stems ≥5cm DBH were classified as trees, and those <5 cm DBH were classified as saplings. Stand Trees/ha Saplings/ha Avg Tree DBH (cm) Gateway 822 281 18 Hasbrouck 513 116 17 North of Pine 424 73 31 Above Brook Farm 642 170 18 P. Dubois 452 112 25 Ridgelands 829 218 20 Gateway Wet 711 251 20 Between Pine and Brook 927 150 19 Average for all stands 665 171 21 Northeastern Naturalist NENHC-40 E.W.B. Russell Southgate and J.E. Thompson 2014 Vol. 21, No. 1 a distinct edge of trees with larger canopies along the southern half of the western edge. This site is also level, but is poorly drained, with several drainage ditches running through it and one channel that is probably a natural stream. Carya ovata (Mill) K.Koch (Shagbark Hickory) dominates the tree stratum, especially trees >20-cm DBH. Hasbrouck Woods also has a variety of oak species, including White Oak, Quercus bicolor Willd. (Swamp White Oak), Q. palustris Münchh (Pin Oak ), and Red Oak. We observed no Eastern Redcedar logs, but there were cut stumps throughout the woods indicating selective logging. This woodlot is adjacent to a farmhouse and likely serves as a major source of wood for the farm. We observed large, open-grown specimens of White Oak (two over 100 cm DBH), Swamp White Oak, Q. coccinea Münchh (Scarlet Oak ) and Shagbark Hickory along the survey lines. The two other stands that were forested in 1946 are North of Pine Farm (NPF; Fig. 4) and Above Brook Farm (ABF; Fig. 5). Both sites are very well drained and sloping, but NPF has abundant conglomerate till in the substrate, and shale dominates at ABF. NPF is on a knoll across Mohonk Creek from an old farmhouse and ABF lies between a field to the east that was still cultivated in 1946 and apparently recently abandoned fields to the west. In 1967, coniferous species dominated the Figure 2. Gateway Woods stems in different size classes by species. Northeastern Naturalist Vol. 21, No. 1 E.W.B. Russell Southgate and J.E. Thompson 2014 NENHC-41 higher part of NPF and along the ravine to the creek. Abundant open-grown trees, especially Sugar Maple, hickories, and Black and Red Oaks grow along the western edge of ABF. Most large open-grown trees growing along stone walls in NPF were Sugar Maple and Scarlet Oak. The presence of dead Eastern Redcedars and stone walls indicate that both stands originated from farm fields, but it is likely that NPF was grazed rather than plowed, given the very rocky nature of the soil. Sugar Maple dominates both stands, whether considering all trees or just trees >20 cm DBH. Acer rubrum L. (Red Maple) and Black Oak are also present in the larger classes at NPF. Other taxa are present as saplings and small trees, including Pinus strobus L. (White Pine) and Quercus prinus L. (Chestnut Oak), and on the upper slope, Eastern Hemlock, Black Gum, and Ulmus americana L. (American Elm). The recent transition from oak to maple dominance is apparent; oak species are present in the tree stratum but are lacking as saplings. Sugar Maple constitutes more than 80% of the stems in all size classes in ABF, and smaller stems predominate. Three forest stands appear to have originated around 1946: P. Dubois, Ridgelands and Gateway Wet Woods (Figs. 6–8). In 1946, the P. DuBois stand had very distinctive field-edge trees, which are present today growing in extensive stone walls; some of these trees have barbed wire embedded in their stems. Field abandonment appears to have occurred around 1946, because the fields looked brushy with no large-diameter trees present in the 1946 aerial photo. It is likely that previously cultivated fields were grazed for several years after active cultivation Figure 3. Hasbrouck Woods stems in different size classes by species. Northeastern Naturalist NENHC-42 E.W.B. Russell Southgate and J.E. Thompson 2014 Vol. 21, No. 1 Figure 5. A b o v e B r o o k F a r m stems in d i f f e r - ent size c l a s s e s by species. Figure 4. North of Pine Farm stems in dif ferent size classes by species. Northeastern Naturalist Vol. 21, No. 1 E.W.B. Russell Southgate and J.E. Thompson 2014 NENHC-43 Figure 7. Ridgelands tree stems in dif ferent size classes by species. Figure 6. P. Dubois woods stems in different size classes by species. Northeastern Naturalist NENHC-44 E.W.B. Russell Southgate and J.E. Thompson 2014 Vol. 21, No. 1 Figure 8. Gateway Wet Woods stems in different size classes by species. ceased. Aerial photographs show that in 1967 a young forest was developing, and that the canopy was mostly closed by 1986. Large open-grown trees present today include Sugar Maple, hickories and White Oak. Eastern Hemlock trees were apparent along Kleine Kill in the 1967 winter aerial photo, and a few are still present. Now, Sugar Maple dominates all size classes. Diverse other species are present here, but occur infrequently. The Ridgelands site was brushy in 1946 east of the Catskill Aqueduct, but was comprised of open tree-lined fields west of the aqueduct. By 1967, the vegetation east and west of the aqueduct was similar. Today, there are abundant open-grown Sugar Maple trees nearby and some Red Oak. There are some downed and some standing dead Eastern Redcedars on both sides of the aqueduct, attesting to the agricultural history of the site. The area to the east of the aqueduct supports the only stand which has abundant native herbaceous vegetation, consisting mainly of Solidago caesia L. (Wreath Goldenrod ) and Eurybia divaricata (L.) G.L.Nesom (White Wood Aster). Today, Sugar Maple dominates all size-classes of trees; some Carya glabra (Mill.) Sweet (Pignut Hickory ) and American Elm are also present. Gateway Wet Woods is similar in soils and topography to Hasbrouck Woods. A drainage ditch crosses the stand and there are many very wet, poorly drained areas. We found one open-grown Swamp White Oak, but when we examined the Northeastern Naturalist Vol. 21, No. 1 E.W.B. Russell Southgate and J.E. Thompson 2014 NENHC-45 aerial photos, the edges of this stand were not clearly marked by open-grown trees. Eastern Redcedar is abundant, but Red Maple dominates the stand. Also common among the trees are Pin Oak and American Elm, a finding consistent with the wet nature of this stand. The now-forested area at the Between Pine and Brook Farms site (Fig. 9) was open field in 1946, rough field in 1967, and young forest in 1986, with some open field areas and large open-grown trees abundant along the edges. We found plastic insulators from modern electric fencing on posts and trees along some of the interior field edges, indicating continued grazing until fairly recently. Eastern Redcedar dominates this forest today, with abundant younger Pin Oak, American Elm and several species of hickory. Field-edge trees were diverse and included Pignut Hickory, Shagbark Hickory, Carya alba (L.) Nutt. (Mockernut Hickory), American Elm, White Oak, Pin Oak, and Prunus serotina Ehrh. (Black Cherry). Harvesting of Eastern Redcedar was apparent, mostly consisting of the removal of one stem from multiple-stemmed trees. Regeneration There are fewer saplings/ha than trees/ha in all of the stands (Table 2). While this small number of saplings may indicate reduced regeneration in these stands, it is difficult to predict the long-term effects of these low sapling numbers at this Figure 9. Between Brook and Pine Farms stems in dif ferent size classes by species. Northeastern Naturalist NENHC-46 E.W.B. Russell Southgate and J.E. Thompson 2014 Vol. 21, No. 1 time. The vigorous regeneration of Sugar Maple on all of the well-drained sites suggests the likely future dominance of this species in all of these stands. In the stands with poor drainage, however, White Ash, Fraxinus pennsylvanica Marshall (Green Ash), and American Elm are common, especially in the older woods. In Hasbrouck Woods, Sugar Maple saplings are more dense than ash or elm. In the youngest stand, there are abundant hickory saplings, as well as elm in some wetter areas and two, probably clonal, patches of Robinia pseudoacacia L. (Black Locust). Discussion Historical records for the study area indicate that oak dominated the pre-colonial forests on slopes and valleys, along with some hickory, American Chestnut, and very little maple. We found that Sugar Maple now dominates most of the stands in this study, in both the tree and sapling layers. Oaks regenerated in the two oldest stands (Gateway and Hasbrouck), but hickory currently dominates the poorly drained site. Sugar Maple dominates the saplings in Gateway, and Sugar Maple and ash dominate the sapling layer in Hasbrouck. On the more steeply sloping sites that support younger forests, there has been almost no recent oak regeneration. Sugar Maple dominates both the tree and sapling strata. These east-facing slopes are the same ones described in a 1794 advertisement as having an oak forest, with occasional hickories and American Chestnuts. Twenty to thirty percent of the saplings at two of the poorly drained sites, Hasbrouck and Gateway Wet, are ash, which is consistent with the 18th-century description of these sites as ash swamps. Changing patterns of herbivory is one possible explanation for the changes in forest structure that we observed. White-tailed Deer were thought to have been extirpated from the New Paltz area by about 1875, with a slow recovery to overpopulation by 1956 (Severinghous and Brown 1956). There is a photograph of a herd of about 150 White-tailed Deer at Brook Farm in 1951 that confirms the importance of White-tailed Deer as browsers when most of the stands in this study were initiated (Daniel Smiley Research Center Archives, New Paltz, NY, unpubl. data). Studies have generally shown that White-tailed Deer prefer oaks to Sugar Maple as a source for browse, though they will eat both (Wakeland and Swihart 2009). White-tailed Deer and other herbivores browse on both acorns and oak seedlings (Marquis et al. 1976). In a study of oak seedling-survival of in an oak-dominated forest in northern New Jersey, browsing by White-tailed Deer and other herbivores eliminated all but 1 of 500 oak seedlings in fourteen 1-m x 1-m plots in 5 years (E.W.B. Southgate, pers. observ). In that study, herbivores likely included rodents and insects, because seedlings inside White-tailed Deer exclosures also mostly disappeared over this time period. The oak canopy may provide an abundance of oak-leaf herbivores that then destroy the seedlings underneath them, adding to White-tailed Deer damage. It appears that both the Hasbrouck and Gateway forests became established at the time of minimum White-tailed Deer density about 100 years ago. Since then, these stands have been exposed to the effects of White-tailed Deer browsing, and the oaks are most likely still suffering from White-tailed Deer browse and perhaps Northeastern Naturalist Vol. 21, No. 1 E.W.B. Russell Southgate and J.E. Thompson 2014 NENHC-47 herbivory by other oak specialists. In addition, oak mast is a favorite food for White-tailed Deer. Grazing on acorns reduces the availability of acorns surviving to sprout, and attraction of deer to sites with acorns also likely results in increased browsing on any oak seedlings present. Seed sources are another likely factor in differences between 18th- and 21stcentury forests on well-drained sites. There is an abundance of Sugar Maples along many field lines, where they probably served as a source of maple sap. Maple sugar was a sufficiently important cash crop that it was reported in the late 19th century Federal Agricultural census data (1850–1880), where several local farms are reported as having produced large amounts. A description of farm life in the early 20th century lists boiling maple sap as a common activity (DuBois 1942). Large, old Sugar Maples produce prodigious numbers of fruits, which have a very high germination rate (Burns and Honkala 1990). Production of seeds is greater in larger trees than in small ones (Burns and Honkala 1990). Although some years are better than others for seed production, there are rarely more than 3 years between abundant crops (Burns and Honkala 1990). The result is that there are often very large numbers of seedlings produced in the vicinity of old Sugar Maple trees (E.W.B. Southgate, pers. observ.). Sugar Maple seedlings can grow in a variety of shade conditions, including deep shade (Nolet et al. 2008). The supply of very large numbers of seeds is at least likely a contributing factor in their recent rise to dominance in these secondary stands. In contrast, oaks produce seeds only in favorable mast years and the acorns are a favorite food of many animals, including White-tailed Deer (Burns and Honkala 1990). Seedlings grow slowly at first and are at a disadvantage when competing with Sugar Maple (Burns and Honkala 1990). However, oaks continue to dominate in the canopy and regeneration layers of forests on higher elevation sites on land that was most likely never farmed (Abrams and Sands 2010). Could fire be a major factor that accounts for the lack of White Oak in stands that originated in the last 50 years, compared with the older White Oak-dominated stand at Gateway? While possible, this seems an unlikely explanation. There is no evidence that farmers burned their regenerating old fields. There is also no evidence that fires in nearby upland forests around a century ago spread down into the agricultural fields (Hubbs 1995). There have been no fires in the younger stands, and it is reasonable to assume that fire in these stands would have thinned or possibly eliminated the fire-sensitive Sugar Maple seedlings. Post-abandonment logging has occurred in at least three of the stands: Gateway, Hasbrouck, and Between Pine and Brook. At Gateway, logging occurred over 100 years ago. It is likely that oak was harvested then; however, this is also the stand with a predominance of oak in the canopy. The logging operation may have selectively left oak saplings, in preference to Sugar Maple, but there is no evidence to either support or refute this conjecture. Selective logging has continued to the present day in the two other stands. The removal of large trees in Hasbrouck Woods has left gaps in the canopy, but Sugar Maple does not appear to have preferentially filled these gaps; the poor drainage most likely has restricted Northeastern Naturalist NENHC-48 E.W.B. Russell Southgate and J.E. Thompson 2014 Vol. 21, No. 1 its spread. Eastern Redcedar has been selectively cut in the Between Pine and Brook stand. Harvest has consisted almost entirely of the removal of one trunk from multiple-trunked trees, and there appears to be little impact of this cutting on forest composition. Sugar Maple consistently occurs as a dominant species across the well-drained sites in our study area, a finding that suggests that this may be an alternative stable state of forest vegetation in this agricultural area (Beisner et al. 2003). The establishment of the shade-tolerant Sugar Maple will prevent the regeneration of shade-intolerant oaks. It appears that a combination of changing herbivory patterns and available seed sources have been important factors in the shift from oak to Sugar Maple. If soil warming enhances Sugar Maple seedling growth as it appears to do for Red Maple, Sugar Maple growth may be further-enhanced by climate change (Butler et al. 2012). This change in forest structure could have cascading impacts on both the fauna and the non-arboreal flora of the area. Changing conditions in the past as well as the future need to be considered to understand factors that affect current ecosystems. Acknowledgments This research was funded by the Loewy Family Foundation as the 2013 Loewy Fellowship to the first author and was carried out at the Mohonk Preserve Foothills. 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