2009 NORTHEASTERN NATURALIST 16(1):85–100 Past and Present Distribution of New Brunswick Bur Oak Populations: A Case for Conservation Donnie A. McPhee1,* and Jude A. Loo1 Abstract - A survey was conducted in New Brunswick (NB) over 5 years (1996– 2000), to assess the status of Quercus macrocarpa (Bur Oak). Bur Oak in NB is separated from the fringe of its contiguous native range by approximately 750 km. Historically, the species occurred throughout the lower Saint John River Valley and in the floodplains of the Grand Lake Complex. The range in NB has been reduced and fragmented, and now consists of a few small populations, along with scattered individuals, occupying a combined area of less than 5 km2. The most isolated of the small populations in NB is at least 40 km from the nearest seed or pollen source. Elements of a conservation strategy are presented, which include preservation of existing stands by government and non-government organizations, landowner education, and restoration planting in appropriate habitats. Introduction Quercus macrocarpa Michx. (Bur Oak) has a broad North American distribution and may become more abundant in the northern portions of its range as the climate warms (Iverson et al. 2005). The populations located in New Brunswick (NB) are separated from the fringe of its present contiguous range by approximately 750 km, and are 250 km from the nearest population, located in Maine. Published species range maps imply that Bur Oak can be found along the lower Saint John River Valley, stretching from Woodstock to the city of Saint John and along the shores of the lakes in the Grand Lake ecosystem and their floodplains (Farrar 1995, Hosie 1979, Loucks 1962, Ritchie 1996). The published range of Bur Oak in NB has been questioned because of the lack of recent observations of the species in these areas. It is known that much of the landscape, once appropriate for Bur Oak habitat, has been cleared for agriculture at one time or another, but the degree to which the distribution and frequency of the species has been reduced was unknown before the present study. In 1996, a survey was initiated to assess the status of Bur Oak in NB and to determine if a conservation strategy was warranted. Species distribution and biology Bur Oak is a member of the Quercus alba L. (White Oak) group. Its contiguous native range extends from south-central Quebec, west to central Manitoba, and funnels down into Texas, with isolated populations located in 1Natural Resources Canada, Canadian Forest Service – Atlantic Forestry Centre, PO Box 4000, Fredericton, NB, Canada. *Corresponding author - dmcphee@nrcan. gc.ca. 86 Northeastern Naturalist Vol. 16, No. 1 the New England states and in the province of NB (Fig.1). Bur Oak is considered to be an important bottomland species throughout much of its northern range, but tolerates a wide range of soil and moisture conditions, making it an associate of many other tree species. It is one of the most drought resistant of the North American oaks and is classified as intermediate in shade tolerance (Farrar 1995, Hosie 1979). Bur Oak is monoecious; male and female flowers are borne in distinct catkins on the current year’s branchlets. The species is generally crosspollinated by small, wind-dispersed pollen grains, for which models predict a long dispersal distance of 199 km (Ducousso et al.1993). Reproductive age spans 35–300 years, and good seed crops are produced every 2–3 years, with either no or light crops in the intervening years. Bur Oak has very large acorns that ripen within the year, drop from the tree at the end of the summer, and are disseminated by gravity, Sciurus spp. (squirrels), Cyanocitta cristata L. (Blue Jay), and water (Johnson 1990). These acorns, unlike most, have low levels of tannic acid, and can be used as a source of human food without requiring treatment. Dicke and Bagley (1980) reported that North American First Nations people ground the sweet-tasting acorns into flour. When plentiful, the acorns make up much of the diet of Blue Jays, Sciurus vulgaris L. (Red Squirrel), and S. carolinensis Gmelin (Gray Squirrel). Aix sponsa L. (Wood Duck), Odocoileus virginianus Zimmerman (White-tailed Deer), Canis latrans Say (Coyote), Ursus spp. (bear), and Mus spp. (mice) and other rodents also feed on Bur Oak acorns (Johnson 1990). When open grown, Bur Oak crowns are usually rounded, but irregular, with the trunk dividing into a number of radiating, crooked, and gnarled Figure 1. Range map of Bur Oak (Quercus macrocarpa) (Little 1971). 2009 D.A. McPhee and J.A. Loo 87 branches. However, when grown in a stand, the crown is usually short, conical, and composed of many horizontal branches. The trunk is straight and tall. On good sites, mature trees grow 20 to 30 m in height, 90 to 120 cm in diameter at 1.3 m above the ground, and live 200 to 300 years (Johnson 1990). The wood is considered to be moderately decay resistant and is not commercially separated from White Oak. It is used for furniture, interior finishing, flooring, and boat building. A plastic-like material called tyloses plugs pores in the wood, making it capable of holding liquids; thus, it is ideal for making barrels (Whitecomb 1985). The species is excellent for urban planting because of its tolerance to automobile emissions, for shelter belts because of its drought tolerance, and as a reclamation species for coal mine spoils because it has fared well on spoils with a pH as low as 5.6 (Geyer and Rogers 1972). There are two recognized forms of the species, Quercus macrocarpa var. macrocarpa Michx. (Southern Bur Oak) and Quercus macrocarpa var. oliviformis (Michx. f.) Gray (Northern Bur Oak), of which the latter is found in Canada and northern US states. Distinguishing characteristics between the two varieties are in morphological and physiological attributes of the acorns. Acorns from the northern variety are smaller and they overwinter, germinating in the spring up to 8 months after falling, whereas acorns of the southern form germinate soon after seed fall (Johnson 1990). Historical context The earliest record of human occupation of the forests of New Brunswick dates back approximately 11,000 years ago, when people entered the Maritime region from the south and southwest (Davis 1991). The first people to influence NB forests were the Mi’kmaq and Malecite First Nations, but the degree of disturbance they caused is not known. Early European missionaries and explorers reported that fire in the woodlands was the greatest single disturbance (Baird 1613, Denys 1672; both cited in McGee 1974), but there are no explicit descriptions of First Nations people using fire in the region as a management tool. Some First Nations are known to have planted Bur Oak as a source of food near their communities (H. Likers, Mohawk council of Akwasasne, pers. comm.), so the pre-European colonization distribution of Bur Oak in the region may have been influenced by locations of Malecite communities. Although the first European settlement in NB was attempted in 1604 on Saint Croix Island, settlement was very slow and of little consequence until after the American Revolution. Parenteau (1994) noted that the European population of what is now NB was fewer than 5000 people in 1784. The colonist population and resulting timber harvest continued to grow steadily but slowly until 1805, when Great Britain offered massive protection to colonial timber on the British market. Population growth followed this development: from 20,000 people in 1800 to 80,000 in 1824 to 150,000 in 1840 (Journal of the Legislative Assembly 1841). As a result, much of the prime land along the Saint John River Valley was cleared for farming or was heavily logged for timber (Bailey 1894). The conversion of the relatively stable floodplain 88 Northeastern Naturalist Vol. 16, No. 1 forest ecosystem to a landscape with a high degree of human disturbance undoubtedly shifted the species composition (Clayden et al. 1984). Bur Oak is one of several floodplain tree species severely affected by the reduction or loss of this ecosystem. Further historical evidence that human intervention was instrumental in shaping the current distribution of Bur Oak in the province as isolated peripheral populations, can be inferred from a study of wood sales recorded in notary deeds in Quebec by Simard and Bouchard (1996). They described how the pre-colonial forest of the Upper St. Lawrence Region changed during the 19th century and reported that at the start of the recorded wood sales in 1800–1809, Bur Oak was the most heavily sold tree, with more than twice the combined sales of all other tree species. By 1850, oak had completely disappeared from the market. The price remained high for oak wood until 1840, after which time it decreased. Simard and Bouchard (1996) concluded that the decrease in oak wood sales could only be explained by the exhaustion of the resource. At the same time, in New Brunswick, Perley (1843) stated that carriage, sleigh, and boat builders all had great demand for Bur Oak wood. He claimed that it was also one of the woods most prized by farmers for agricultural implements. Documented Bur Oak in New Brunswick Bur Oak is documented in greatest abundance in the Grand Lake Lowlands Ecoregion (Loucks 1962), a low-lying trough in south-central NB encompassing the areas surrounding the Grand Lakes (Grand, Indian, French, and Maquapit Lakes) and the broad valleys associated with the Saint John and Oromocto rivers (Fig. 2) (Zelazny 1997). The region has the warmest climate in the province, with an annual growing degree day (>5 °C) total that sometimes exceeds 180 (Atmospheric Weather and Environment Service 1993). The shallow, broad basin, within which are large bodies of water, is less prone to the formation of frost pockets than elsewhere in the province because of the moderating effect of the water. This moderation reduces the number of late spring and early fall frosts, creating a long frostfree season of approximately 150 days. The winter climate in the region is more typical of the surrounding areas because the frozen lakes and rivers have no moderating effect (Dzikowski et al. 1984). Soils in the ecoregion—predominantly deep, heavy, clay loams—have moderate to low fertility. The relatively flat topography and low elevation (generally less than 45 m above sea level) are underlined with formations of coarse-textured quartzose sandstone and fine-textured red siltstone of Carboniferous origin (Colpitts et al.1995, Stobbe 1940). Imperfectly to poorly drained fine sands, silts, and clays occur along the river flood plain. The warm temperatures and extensive alluvial plains provide habitat for several species in addition to Bur Oak that are at or near the northern limit of their eastern range, including Acer saccharinum L. (Silver Maple), Fraxinus pennsylvanica Marsh. (Red Ash), Fraxinus americana L. (White Ash), Juglans cinerea L. (Butternut), Ostrya virginiana (P. Mill.) 2009 D.A. McPhee and J.A. Loo 89 (Hop-hornbeam), and Tilia americana L. (Basswood) (Zelazny 1997). Bur Oak has also been documented historically in the Valley Lowlands Ecoregion, where floodplains may host an assemblage of species similar to that of the Grand Lake Basin Ecoregion (Ecosystem Classification Working Group 2003, Zelazny 1997). The province of New Brunswick has ranked Bur Oak as a species that “may be at risk” and is therefore a candidate for research priority or detailed risk assessment (New Brunswick Department of Natural Resources and Energy 2003) More recently, Bur Oak has received an S-ranking of S2 by the Atlantic Canada Conservation Data Centre (NatureServe 2008), indicating that the species is rare in the province, thus making it vulnerable to extirpation. In the present study, the historic range of Bur Oak was surveyed throughout New Brunswick to determine accurately the current range, distribution, and frequency of Bur Oak in the province and to determine if conservation measures are warranted for these populations. In addition, a stand evaluation was conducted to develop a prognosis for each population. The prognoses were based on visual inspection of each population, including the production of viable seedlings and the structure-class distribution. Survey Methods The survey was conducted in three stages in 1996–1997 throughout the Saint John River Valley and Grand Lake Basin Ecoregion. The first stage consisted of a literature review to determine and validate the historical range of Bur Oak in New Brunswick. The second stage, during the spring of 1996, focused on gathering evidence of recent occurrences, either documented or anecdotal, collected by searching herbaria and communicating with local botany experts. The final stage, conducted in the spring and summer of 1996 and 1997, consisted of a thorough search throughout the historical species range as follows: 1) Road systems were driven. A large percentage of the floodplain and riverbanks are visible from the extensive road system that lines the Grand Lake Basin Ecoregion and Saint John River. 2) The waterways of the Grand Lake Basin Ecoregion were covered by boat to gain access to areas not accessible by the road systems and to search the islands and marshlands. All small lakes and inlets were surveyed. This exercise was conducted in the early spring, before leaf flush, in order to see the species’ distinct crown form. It also allowed access to a much higher percentage of the actual floodplain of the ecoregion than would have been possible later in the year. 3) Other areas considered to have a reasonable probability of having Bur Oak, based on aerial photograph interpretation, that were not investigated during the road and waterway surveys, were examined on foot. Land ownership was determined for each Bur Oak site identified as a result of this survey, and sites were revisited in the summer of 1997 for evaluation. The following information was collected during the site evaluation: number of Bur Oak trees (approximate number in the largest 90 Northeastern Naturalist Vol. 16, No. 1 populations), area occupied by the population, structure classes of the trees, physical habitat description, associated plant species, and present and expected future land uses on the site and in surrounding areas. Finally, current and future threats to the sites were deduced on the basis of present and expected land use. All mature and sapling-sized trees were counted or approximated, and seedling numbers were estimated by a thorough ground search of each site and surrounding area. Trees were classified as mature if they showed evidence of reproduction. Saplings were defined as trees taller Figure 2. Ecoregions of New Brunswick: Ecoregion 7, Grand Lake Basin; Ecoregion 5, Valley Lowlands (Zelazny et al. 1997). 2009 D.A. McPhee and J.A. Loo 91 than 1.5 m, but reproductively immature; any tree shorter than 1.5 m was considered a seedling. The population boundaries, along with individual mature tree locations within the populations, were mapped on aerial photographs and the area occupied by each population was calculated. A prognosis for persistence of each stand beyond the present generation, based on production of viable acorns and seedlings, was derived after four consecutive summers (1996–1999) of field observations. Results Excluding individual trees or isolated clumps of small numbers of trees (less than 10), there are eight populations of Bur Oak in NB, only one of which has more than 500 mature trees (Table 1). In addition, only one of the eight populations has protected status (Table 2). The rest are all on privately owned land. Bur Oak is no longer found in much of its historic range in New Brunswick, and many of the remaining stands are threatened by development (Table 2). Most of the Bur Oak populations occur as mixed floodplain forest patches, with Silver Maple and Acer rubrum L. (Red Maple) being the two most commonly associated tree species. Seven of the eight sites where Bur Oak is a major component are around the Grand Lake complex, and the eighth site is on Belleisle Bay. In addition, the species can still be found Table 1. Location and structure-class distribution of Bur Oak populations in New Brunswick, Canada. Population Approximate number of # Name and location Mature trees Saplings Seedlings 1 Apple Island 65 100 150 2 Lakeville Corner 100 150 200 3 Denton Point 56 50 100 4 Douglas Harbour 200 100 200 5 Iron Bound Cove 59 0 200 6 Cox Point 500 500 1000 7 Jemseg 64 20 300 8 Erb’s Cove 49 25 30 Table 2. Ownership, land area, and threats to long-term survival of Bur Oak populations in New Brunswick, Canada. Approximate Time of Population Ownership area* (ha) threat Type of threat 1. Apple Island Private 1.8 None None 2. Lakeville Corner Private 18.0 Current Development 3. Denton Point NB Nature Trust/ Private 2.4 None None 4. Douglas Harbour Private 9.0 Current Development 5. Iron Bound Cove Private 2.4 None None 6. Cox Point Private 360.0 Future Development 7. Jemseg Private 15.0 Current Grazing 8. Erb’s Cove Private 1.8 Current Harvesting *Approximate area was obtained from aerial photographs. 92 Northeastern Naturalist Vol. 16, No. 1 as a minor component in the Cambridge Narrows area and a few isolated trees occur in Keswick Ridge and surrounding areas (Fig. 3). All of the New Brunswick populations occur in narrow bands on floodplains or riverbanks, and the most frequently associated shrub and herbaceous species are typical of bottomland ecosystems (Table 3). Each of the sites and associated threats are briefly described below. Apple Island (Population 1), located in the middle of French Lake, appears to be relatively undisturbed. The landowner has no current plans to alter the island’s natural state. The small stand is located on a floodplain in a shallow cove on the west end of the island and has a fairly even representation of structure classes. There is a noticeable absence of Bur Oak on the shores of the rest of the island, where the banks are characterized by steep rocky slopes and are exposed to high winds and lashing waves. Lakeville Corner (Population 2) is located at the mouth of the “Blind Thoroughfare,” a narrow strait, which runs between the French and Maquapit Lakes. The property is owned by three private landowners and is under serious threat due to residential and cottage development. The population consists of a wide range of structure classes, including acorn-producing, Figure 3. Remaining Bur Oak populations in New Brunswick. 2009 D.A. McPhee and J.A. Loo 93 mature trees. The site is a combination of river meadow and floodplain, with the floodplain gradually rising into agricultural land, where a few mature acorn-producing trees persist. In 1995, the stand was estimated to cover an area of approximately 22 ha. This was reduced in 1997 by 4 ha, and again in 1999 by another 4 ha. Denton Point (Population 3) is partially owned by the Nature Trust of New Brunswick. The small population, located on a 25-m wide strip of forested floodplain in a small sheltered cove, is the only Bur Oak site in New Brunswick that has legal protected status. The entire floodplain on either side of the protected area is currently being developed for summer homes. A large population, consisting of a wide range of size classes, is located on the floodplain of Douglas Harbour and on Earl Island (Population 4). The population is located on a narrow strip, approximately 30 m wide, around the edge of the island and along the shore of the cove. Biologically, the population appears to be viable, with adequate regeneration and survival of seedlings for long-term persistence, but the area is slowly being reduced. Recently, the island has been subdivided and advertised on the real estate market. The shores of the harbor continue to be developed for residential purposes, constituting a serious and immediate threat to this population. Iron Bound Cove (Population 5) is located at the far northeast end of Grand Lake where the Salmon River empties into the Salmon Bay. The population, consisting of mature trees and seedlings with a noticeable absence of saplings, is located in a small cove, protected by an island running parallel to the shore for approximately 600 m. The Bur Oak trees at this site are situated on the floodplain of the shallow cove and on the island, which is typical floodplain terrain. The area inland from the site is an active open-pit Table 3. Common associated species at Bur Oak sites. Species Common name Preferred habitat* Acer rubrum L. Red Maple Moist, well-drained, sandy loams Acer saccharinum L. Silver Maple Moist bottomlands, freshwater shores Alnus rugosa Du Roi Spreng. Speckled Alder Wet areas along streams and in swamps Fraxinus pennsylvanica Marsh. Red Ash Wet bottomlands, near waterways Agrostis scabra Willd. Fly-away Grass Lake shores and bog trails Cornus sericea L. Red Osier Meadows and shores Ilex verticillata L. Winterberry Swampy or boggy open woods Maianthemum canadense Desf. Wild Lily-of-the-valley Moist, usually acid woods Onoclea sensibilis L. Sensitive Fern Wet open woods and meadows Osmunda claytoniana L. Interrupted Fern Moist woods and thickets, bottomlands Rubus pubescens Raf. Swamp Red Raspberry Moist thickets, woods, and shores Smilax herbacea L. Jacob’s Ladder Alluvial woods, shores, and meadows Spiraea alba Du Roi Meadow Sweet Meadows and shores Vaccinium myrtilloides Michx. Velvet Leaf Blueberry Clearings, thickets, peat bogs *From Hinds (2000). 94 Northeastern Naturalist Vol. 16, No. 1 coal mine, which has been completely stripped of all vegetation in the recent past. The area hosting Bur Oak has recently been purchased from the mining company by a private landowner. At present, the site appears to be safe from further habitat loss, as the new landowner has expressed an interest in site reclamation and in the re-establishment of the Bur Oak forest to the areas that have been disturbed by past mining operations. Cox Point (Population 6) is located on a peninsula at the northeastern end of Grand Lake and constitutes the largest continuous population in the province. The edge of the peninsula has numerous inlets and coves that host small pockets of regenerating Bur Oak. The peninsula is not uniformly low-elevation floodplain, having scattered small hills and knolls; however, many of the inlets stretch from one side of the peninsula to the other, so Bur Oak occurs throughout the entire area. There are currently no known development plans for the site, which has a single owner. However, considering its highly valued location and the growing interest in summer cottage development in the area, the site is not secure in the absence of legislated protected status. The Jemseg population (Population 7) is divided between two distinct land uses. The largest area was, until recently, used as pasture land. Fortyfour mature Bur Oak trees were left to provide shade for cattle and although many of the trees produced acorns, there was no regeneration present on the site until 2 years following the removal of the cattle. Approximately one-third of the 44 trees show signs of severe deterioration, and appear to be past their reproductive years. A small wooded area adjacent to the pasture (0.4 x 0.2 km) extends from the floodplain and rises to approximately 25 m over a distance of 200 m. A group of 20 mature trees, with ample regeneration, occurs in this forested section, which has two owners, neither of whom expressed any plans for clearing the area. However, over the course of this study, two new homes were built on the site, resulting in a loss of 2–3 ha of habitat. The eighth and smallest distinct population (Population 8), is located in the Valley Lowland Ecoregion at the far end of Erb’s Cove on Belleisle Bay, on the slopes of the steep ravine that forms the banks of Peters Brook. There is little regeneration and, due to the economic value of the wood to the landowner, there is a constant threat of harvesting. The landowner relies on harvesting fuel wood for his major source of income. The cove is typical floodplain and is currently used as cow pasture. In addition to the eight populations of Bur Oak located by this survey, scattered individual trees were mapped throughout the Saint John River Valley and Grand Lake region. The area from Woodstock to Keswick Ridge, a distance of more than 80 km, revealed only two young trees (approx. 50 years old) located on an upland slope approximately 20 km west of the Mactaquac dam. Neither tree produced acorns during the course of this survey. The river valley from Keswick Ridge to Gagetown Island, approximately 60 km in length, revealed only two Bur Oak sites. Three mature trees occur on the front lawn of an active dairy farm in Keswick Ridge, and five trees persist 2009 D.A. McPhee and J.A. Loo 95 in Maugerville on floodplain that is currently used as pasture land. The trees at both of these locations produce acorns; however, because of the location of the trees, no seedlings have survived. The Grand Lake region also contains a few scattered pockets of Bur Oak with fewer than 40 trees. Eight trees occur on the lawns of lakeshore cottages at the northwestern corner of French Lake, and Maquapit and Grand Lakes have scattered individual mature trees located along their northern shores. However, little to no regeneration has been observed in the areas surrounding the trees. In 1996, a small pocket of mature trees was located at Flowers Cove on Grand Lake; however, they were cleared for cottages sometime between the springs of 1996 and 1998. Nine mature trees were found along the river’s edge just north of the village of Gagetown. Two mature trees, 15–20 saplings, and numerous seedlings were located on the east side of Hart Lake. This area was once farmed, but has been abandoned for approximately 20 years. Twenty-eight mature trees were located along a 4.5-km section of the eastern bank on the Jemseg River, but there was very little regeneration occurring at this site. Five trees remain at Cambridge Narrows, and two in Springfield. These trees produce acorns; however, all were surrounded by active farmland and no regeneration was observed. Discussion Outside of New Brunswick Bur Oak is one of the most widespread of all the white oaks. Throughout its contiguous range, there is little concern about its viability. However, in the New England states, where it occurs as small isolated populations, little has been published or is known about its status. NatureServe compiles information from Natural Heritage programs in the US and Conservation Data Centers in Canada on occurrences of uncommon species throughout North America. Information provided by NatureServe (February 2008) provided a status ranking for Bur Oak in the northeastern US of SR for Maine and Vermont, indicating that its status is unknown. Bur Oak is listed in the “Checklist of Vascular Plants of Maine” (Campbell et al. 1995) in seven counties, and is not considered to be rare (D. Cameron, Maine Department of Conservation, Augusta, ME, pers. comm., February 2008). In Vermont, Bur Oak is known to occur in all six counties bordering Lake Champlain, and is not viewed as a species of concern by the Vermont Fish and Wildlife Department (B. Popp, VT Fish and Wildlife Department, Waterbury, VT, pers. comm., February 2008). In New Hampshire and Maryland, Bur Oak’s rank is S1, denoting critically imperilled (1 to 5 occurrences, with 1000 or less individuals; B. Nichols, The Nature Conservancy, Concord, NH, pers. comm., February 2008), whereas in Massachusetts and Connecticut, Bur Oak has a ranking of S3, denoting uncommon or restricted range. Currently, Bur Oak has an S ranking of S3S4 in Quebec (uncommon in the northeast, 96 Northeastern Naturalist Vol. 16, No. 1 but becoming apparently secure in the lower southwestern St. Lawrence River Valley), and S4 (secure) in New York. In Ontario, it is listed as S5, indicating that it is widespread, abundant, and secure throughout its range in the province. Natural Bur Oak occurrence outside ornamental plantings has never been documented in either Nova Scotia or Prince Edward Island (NatureServe 2008). Within New Brunswick It is apparent that the distribution and abundance of Bur Oak have been reduced in New Brunswick. The question is whether this reduction has been so severe that the species is threatened both in terms of genetic diversity and its persistence in the province. If so, what might be the consequences of losing the species from New Brunswick? Herbarium records (1880–1995), along with historical literature, support published species range maps for Bur Oak in New Brunswick. These records indicate that Bur Oak, although never a common species, did occur in scattered pockets along the lower Saint John River Valley, between Woodstock and the city of St. John. Today, with the exception of a few scattered trees, the range of Bur Oak in New Brunswick has been reduced to a combined area of less than 500 ha, of which only 2.4 ha is protected. With no known historic environment-, insect-, or disease-related causes, human intervention (specifically, land clearing for development) is the likely cause of the decline of Bur Oak in New Brunswick. The history of the Saint John River Valley includes over 200 years of intense agriculture and logging along the river, lakeshores, and floodplains, with most areas having been cleared at one time or another (Power and Matson 1995). Dam construction for hydroelectricity at Beechwood (1957) and Mactaquac (1968) has permanently flooded sections of the Saint John River natural floodplain. Hinds (1983) determined that the flooding caused by these dams was responsible for the elimination of four vascular plants (Solidago ptarmicoides (Nutt.) Nesom [Prairie Goldenrod], Celastrus scandens L. [American Bittersweet], Desmodium glutinosum (Muhl. ex Willd.) Wood [Largeflower Tickclover], and Sporobolus asper (Michx.) Kunth [Composite Dropseed]) from the provincial flora of New Brunswick. In addition, the historical bottomland habitat upriver of the Mactaquac dam, where Bur Oak populations likely occurred, has been flooded and no longer exists. The two young trees discovered near Bear Island may be remnants of a previous population in the area of the original floodplain. Human demands continue on land that provides suitable habitat for Bur Oak and other floodplain species. From the beginning of this study in 1996 until 1999, many areas along the river and lake shores have been altered as a result of upgrading highways, cranberry field development, construction of marinas, and residential or cottage development. Of the eight identified populations, three are currently threatened by development of homes and cottages. As indicated by the common flora at these sites (Table 3), they are 2009 D.A. McPhee and J.A. Loo 97 all naturally poorly drained and would not historically have been considered “prime” real estate. However, increased demand for new waterfront cottage lands combined with the use of fill, the ease of road construction, and wetland drainage has rendered these once remote and inaccessible sites popular development areas. Mature trees are sometimes left as shade trees at sites developed for cottages (e.g., at Lakeville Corner, Douglas Harbour, and Jemseg), giving the appearance of an intact stand. However, a stand under such conditions will likely only persist as long as the existing trees survive, and thus cannot be considered to be part of a viable population. Currently, there appears to be little demand for Bur Oak wood as a lumber species; however, this may be due to the lack of supply. There are two local anecdotes about Bur Oak being harvested for its timber, involving the populations of Douglas Harbour and Jemseg. In Douglas Harbour, the current landowner recalls a local sawmill owner approaching his parents in the early 1960s, and being granted the right to harvest a number of mature trees. During the early 1980s, a local researcher with the Canadian Forest Service (CFS) visited a landowner in the Jemseg area to inquire about the Bur Oak on his property. The landowner was hauling the trees off to a sawmill as the researcher arrived at the property (D.P. Fowler, CFS (retired), Fredricton, NB, Canada, pers. comm.). Additional harvesting of Bur Oak in the region (Lakeville Corner, Douglas Harbour, Flower’s Cove, and Erb’s Cove) has been a result of encroachment, with the Bur Oak wood, along with other floodplain hardwoods, being used for fuel. Bur Oak is a phenotypically plastic species, adapted to warmer climates in most areas of its broad range. It is one of the species that may be expected to move into the Maritime region as climate warming occurs. Bur Oak occurring in New Brunswick is adapted to the photoperiod of this latitude and, if sufficient genetic diversity exists in the remaining small populations, they would form the nucleus of the northward expanding distribution of the species into the region. The distribution and abundance of natural Bur Oak populations are still shrinking in New Brunswick (as shown by the clearing of portions of both the Lakeville Corner and Douglas Harbour populations during the course of this study), potentially resulting in the loss of valuable genetic variation in adaptively important traits in these outlying populations. Outlying populations sometimes contain atypical genetic variation in response to harsher environments at the edges of the ecological range of the species. Such genetic variation may contribute to the processes and systems that are likely to provide future adaptive potential for the species (Lesica and Allendorf 1995). With climate change models predicting an increase in mean annual temperatures as high as 3 °C, plant species’ ranges could theoretically shift on the order of 500 km in the next century (Falk et al. 1996, US Forest Service 2008). Northern outliers of a generally more southern species, such as Bur Oak in New Brunswick, may become important sources of genetic material, giving the species an advantage through long-term climate changes and species range shifts. 98 Northeastern Naturalist Vol. 16, No. 1 Conclusions and Recommendations Conservation measures are required to maintain natural populations of Bur Oak in New Brunswick, and restoration is recommended to expand the current distribution. The first and most basic step is education, ensuring that those who have an influence on existing Bur Oak populations, including owners, government departments, and non-governmental land-protection organizations, are aware of the status and the need for conservation. Although current landowners have been made aware of the status of the species and the rationale for conserving populations, the fact that all of the unprotected sites are privately owned on land having significant development value, means that the populations face a high degree of insecurity. Land trusts have expended some efforts on acquiring Bur Oak sites, but they are limited in the purchase prices they can offer; for example, they may not be allowed to exceed the assessed value of the land, which is influenced by flood maximums. Because of the high and increasing demand for such land for cottage development, however, the landowners can often obtain more than the assessed value on the open market and are thus unlikely to sell the land at the lower price that can be offered by a land-conservation organization. Efforts to acquire land or to establish easements must, however, continue. Restoration holds promise, as the trees grow well on a variety of sites, and woodlot owners in southern and central New Brunswick have demonstrated an interest in planting Bur Oak on their land. Ideally, a local nursery will become interested in providing locally adapted stock to landowners. Seed should be collected from as many trees in as many populations as possible, and seedlings should be distributed to interested landowners in areas where the species was once found. Acknowledgments The authors would like to thank Preeti Ramprasad, Beth Arsenault, and Kathleen Forbes for their assistance in surveying and ground proofing Bur Oak sites, Don Fowler and the late Hal Hinds for their guidance in getting this survey up and running, the many private woodlot owners for allowing us to conduct this survey on their lands, and the New Brunswick Department of Natural Resources for providing helpful mapping information. We thank Dale Simpson, Vince Zelazny, and two anonymous reviewers for kindly reviewing the manuscript. Literature Cited Atmospheric Weather and Environment Service. 1993. Canadian climate normals 1961–1990: Atlantic Provinces. Environment Canada. AES Publishers, Ottawa, ON, Canada. 105 + iii pp. Bailey, J.W. 1894. The Saint John River in Maine, Quebec, and New Brunswick. Fisher Library, Woodstock, NB. (Cited in A. MacDougall and J. Loo. 1997. Natural History of the Saint John River Valley Hardwood Forest of Western New Brunswick and Northeastern Maine. Natural Resources Canada, Canadian Forest Service – Atlantic Forestry Centre, Fredricton, NB, Canada. Information Report M-X-2004E. 62 pp.) 2009 D.A. McPhee and J.A. Loo 99 Baird, P. 1613. Jesuit relations. Paris, France. (Cited in S.G. Lutz. 1997. Pre-European settlement and present forest composition in King’s County, New Brunswick, Canada. Master of Forestry Thesis. University of New Brunswick, Fredericton, NB, Canada. 48 pp.) Campbell, C.S., H. Adams, P. Adams, A. Dibble, L.M. Eastman, S.C. Gawler, L. Gregory, B. Gnunden, A.D. Haines, K. Jonson, S.C. Rooney, T.F. Vining, J.E. Weber, and W.A. Wright. 1995. Checklist of the vascular plants of Maine. Third revision. Maine Agricultural Experiment Station, Orono, ME. Technical Bulletin 844. Clayden, S.R., D.F. McAlpine, and C. Guidry. 1984. Rare and Vulnerable Species in New Brunswick. Natural Science No. 2. The New Brunswick Museum, Saint John, NB, Canada. 95 pp. Colpitts, M.C., S.H. Fahmy, J.E. MacDougall, T. Ng, B.G. McInnis, and V.F. Zelazny. 1995. Forest soils of New Brunswick. CLBRR Contribution No. 95-38. Agriculture and Agri-Food Canada and New Brunswick Department of Natural Resources and Energy, Fredericton, NB, Canada. 51 pp. Davis, S. 1991. The Micmac. Four East Publications, Tantallon. NS, Canada. (Cited in S.G. Lutz. 1997. Pre-European settlement and present forest composition in King’s County, New Brunswick, Canada. Master of Forestry Thesis. University of New Brunswick, Fredericton, NB, Canada. 48 pp.) Denys, N. 1672. The description and natural history of the coasts of North America. Reprinted at the Champlain Society in Toronto, ON, Canada, 1908. (Cited in S.G. Lutz. 1997. Pre-European settlement and present forest composition in King’s County, New Brunswick, Canada. Master of Forestry Thesis. University of New Brunswick, Fredericton, NB, Canada. 48 pp.) Dicke, St. G., and W.T. Bagley. 1980. Variability of Quercus macrocarpa Michx. in an eastern Nebraska provenance study. Silvae Genetica 29(5–6):171–177. Ducousso, A., H. Michaud, and R. Lumaret. 1993. Reproduction and gene flow in the genus Quercus L. Annales des Sciences Forestières 50(1):91s–106s. Dzikowski, P.A., G. Kirby, G. Read, and W.G. Richards. 1984. The climate for agriculture in Atlantic Canada. Atlantic Advisory Committee on Agrometeorology, Edmonton, AB, Canada. ACA 84-2-500. Ecosystem Classification Working Group. 2003. Our landscape heritage: The story of ecological land classification in New Brunswick. Department of Natural Resources, NB, Canada. CD-Rom document. Falk, D.A., C.I. Millar, and M. Olwell. 1996. Restoring Diversity. Island Press, Washington, DC. 505 pp. Farrar, J.L. 1995. Trees in Canada. Canadian Forest Service, Fitzhenry and Whiteside, Markham, ON, Canada. 502 pp. Geyer, W.A., and N.F. Rogers. 1972. Spoils change and tree growth on coal-mine spoils in Kansas. Journal of Soil and Water Conservation 273:114–116. Hinds, H.R. 1983. The Rare Vascular Plants of New Brunswick. National Museums of Canada, Ottawa, ON, Canada. Syllogeus No. 50. 38 pp. Hinds, H.R. 2000. Flora of New Brunswick. Department of Biology, University of New Brunswick, Fredericton, NB, Canada. 699 pp. Hosie, R.C. 1979. Native Trees of Canada. Fitzhenry and Whiteside Ltd., Canadian Forestry Service, and Canadian Government Publishing Centre, Supply, and Service, Don Mills, ON, Canada. 380 pp. Iverson, L.R., A.M. Prasad, and M.W. Schwartz. 2005. Predicting potential changes in suitable habitat and distribution by 2100 for tree species of the eastern United States. Journal of Agricultural Meteorology 61:29–37. 100 Northeastern Naturalist Vol. 16, No. 1 Johnson, P.S. 1990. Quercus macrocarpa Michx. Bur Oak. Pp. 686–692, In R.M. Burns and B.H. Honkala (Technical Coordinators). Silvics of North America: 2. Hardwoods. Agriculture Handbook 654. US Department of Agriculture, Forest Service, Washington, DC. 877 pp. Journal of the Legislative Assembly. 1841. Census of New Brunswick. Government of New Brunswick, Fredricton, NB, Canada. (Cited in S.G. Lutz. 1997. Pre-European settlement and present forest composition in King’s County, New Brunswick, Canada. Master of Forestry Thesis. University of New Brunswick, Fredericton, NB, Canada. 48 pp.) Lesica, P., and F.W. Allendorf. 1995. When are peripheral populations valuable for conservation? Conservation Biology 9(4):753–760. Little, E.L., Jr. 1971. Atlas of United States Trees, Volume 1. Conifers and Important Hardwoods. US Department of Agriculture, Washington, DC. Miscellaneous Publication 1146. 9 pp., 200 maps. Loucks, O.L. 1962. A forest classification for the Maritime Provinces. Forest Research Branch, Department of Forestry, Fredericton, NB, Canada. 167 pp. McGee, H.F. 1974. The Native Peoples of Atlantic Canada: A Reader in Regional Ethic Relations. McClelland and Stewart, Ltd. Toronto, ON, Canada. 211 pp. NatureServe. 2008. Nature Server Explorer. Available online at http://www.natureserve. org/explorer/servlet/NatureServe?searchSciOrCommonName=Bur+oak& x=8&y=8. Accessed February 2008. New Brunswick Department of Natural Resources and Energy. 2003. General status of wildlife in New Brunswick: Draft vascular plant status. Fredricton, NB, Canada. Parenteau, B. 1994. The New Brunswick Forest Heritage: A History of the Forest Industries, 1780–1930. Unpublished report prepared for Historic Sites and Monuments Board of Canada. Parks Canada, Halifax, NS, Canada. Perley, M. 1843. Report on the forest trees of New Brunswick. Pp. 129–427, In Simmonds’ Colonial Magazine, Vol. XI No.42.,Toronto, ON, Canada. Power, R., and B. Matson. 1995. Ecological land classification of southeastern New Brunswick. Department of Natural Resources, Fredericton, NB, Canada. Ritchie, G.A. 1996. Trees of knowledge. Natural Resources Canada, Canadian Forest Service – Atlantic Forestry Centre, Fredericton NB, Canada. 41 pp. Simard, H., and A. Bouchard. 1996. The precolonial 19th-century forest of the upper St. Lawrence Region of Quebec: A record of its exploitation and transformation through notary deeds of wood sales. Canadian Journal of Forest Research 26:1670–1676. Stobbe, P.C. 1940. Soil survey of the Fredericton–Gagetown area of New Brunswick. Publication 709, Technical Bulletin 30. Dominion of Canada and New Brunswick Department of Agriculture, Fredericton, NB, Canada. 51 pp. US Forest Service. 2008. Climate change atlas. Available online at http://www.nrs. fs.fed.us/atlas/tree/tree_atlas.html. Accessed February 2008. Whitecomb, C.E. 1985. Know it, Grow it II. A Guide to the Identification and Use of Landscape Plants. Lacebark Publications, Stillwater, OK. Zelazny, V. 1997. Ecological land classification for New Brunswick: Ecoregion, ecodistrict, and ecosite level. Forest Management Branch, New Brunswick Department of Natural Resources. Fredericton, NB, Canada. 59 pp.