Belt Woods: Tree Heights and Forest Structure in the South Woods
This study provides the maximum heights reached by forty-two species of trees measured in the South Woods in October 2001. These laser-derived measurements provide additional proof of the unique quality of this site, and aid in an overall understanding of the role of tree height capabilities in creating the existing forest structure. Correlations between maximum tree heights, indicator species, habitat influences, and historic references are explored.
Description of Site
The South Woods is a 43-acre National Natural Landmark located at the southeast end of the Belt Woods natural area, which is a 624-acre mosaic of small fields and woodland located in east-central Prince Georges County, Maryland. Owned by the State of Maryland, access is by permit, and limited to scientific study.
Often termed the last example of old-growth forest in the Mid-Atlantic region, the woodland has been of considerable interest for many years. As early as 1947, studies by Stewart and Robbins showed the site to have unusually high densities of forest interior dwelling birds. A nearby tract, the North Woods, also was of old-growth character, but its large white oaks and tuliptrees were cut in 1981. This caused the State of Maryland, with the assistance of others, to purchase 109 acres in 1984, which protected the South Woods. By 1997, impending residential development necessitated the States purchase of an additional 515 acres. The entire property is designated as the Belt Woods Wildland.
The South Woods is somewhat triangular in shape. It is bounded on the east by Church Road, and Central Avenue (Maryland Route 214) on the south. Contours rise gradually from about 140 feet at Church Road to over 180 feet on a crescent-shaped ridge, and then rather steeply down-slope to approximately 125 feet at the southwest corner. To the north and northwest, remnants of an old forest/field interface form an irregular natural boundary.
The soils are primarily Collington fine sandy loam derived from a greensand deposit rich in glauconite, and are extremely fertile, as evidenced by the presence of Cimicifuga, Collinsonia, Dioscorea, Heuchera, broad beechfern, lady fern, and several small patches of glade fern and maidenhair fern. The central ridge is somewhat drier, especially on the south-facing end, where the slopes are Monmouth loamy sand. The ridge is more acidic at the northwest boundary, where some spotted wintergreen and early low blueberry occur. An abundance of Smilax rotundifolia indicates wetter Shrewsbury silt loam soils in the low southwestern section and small areas in the northernmost section. A small nearly level area of Adelphia silt loam occurs at about the mid-point of the Church Road boundary.
The South Woods is dominated by large white oaks and tuliptrees, with occasional large black oaks and northern red oaks. The northeast section of the woodland is dominated by a dense stand of mature tuliptrees, probably of old-field origin. Some very large tuliptrees occur, especially in the northernmost portion. Mature hickories are an important forest component, and are scattered throughout most of the stand.
In the southwest section, trees of all heights and ages are present, including many large specimens. In the southeast and northeast sections, the woods is height-segregated more by species than by age classes. Few submature examples of the larger tree species rise above the understory, even in windthrow openings. The dense understory consists of flowering dogwood and spicebush, with some blackhaw viburnum, ironwood, and small American beech. This severely shades the soil, and hinders successful seeding by the larger tree species. Japanese honeysuckle is common, but seldom a serious factor, due to the dense shade. Birds are important in spreading seeds of these understory species. The woods is more open on the ridges and upper slopes, due to the essential absence of spicebush.
The interfaces at the boundaries of the South Woods add some diversity. Some sun reaches areas above road banks on Church Road, but most of that border is dominated by young hickories. The southern boundary is influenced by Route 214 and a utility right-of-way. American elms, river birch and other intolerant species, both native and naturalized, occur here. At the irregular northwest border, a few river birch, red maple, mazzard cherry, black walnut and sassafras occur with many large side-spreading oaks and tuliptrees. The adjoining old-field growth, principally tuliptrees and black locusts, is reducing sunlight for the older border.
The South Woods is often called an example of old-growth forest. Such is not inappropriate, considering the numerous specimens of white oak over 200 years old, with heights to over 140 feet. The trunk of a windthrown white oak on the southeast roadside has been sawed at a point forty inches in diameter, and appears to be about 240 years old. Some tuliptrees may be over 200 years old, but most appear younger, probably in the 120-140 year range. At least seven tuliptrees are over 150 feet tall. Many black oaks are quite old, as evidenced by some dieback, and the shedding of outer bark, exhibiting a tight, light gray surface. Mature hickories occur throughout the stand. Large northern red oaks are scattered throughout the woods; maximum height is over 140 feet.
Excepting the transitional borders, there is limited diversity. This conforms to Chryslers statements (Shreve, 1910) regarding the original forests found on these soils. Chrysler states (p.196) that Collington soils support the most mesophytic vegetation of the region, and (p.170) the original Forest of Prince George consisted of white oak, black oak, hickories and tuliptree, with chestnut on the higher parts of slopes, and with seedlings of the same species. Stewart and Robbins (1958) quote Harper (1918): Rich moist upland forests, composed chiefly of white oak and tulip-poplar, occur locally and are especially prominent in east-central Prince Georges County on the fertile soils of the Greensand district. Chrysler also holds (p.169) that maple and beech were not a major component of the forest. Therefore, the infrequent occurrence of beech and red maple does not seem to be fire-related. The hickories show no basal cavities or other fire damage, suggesting the absence of fire for well over a century.
The map of the 1907 state forest survey (Besley, 1916) shows the nearly triangular outline of the South Woods, much like that of today, and rates the stand as M, that being merchantable hardwoods of 2000-6000 board feet per acre. M was the highest rating used for Prince Georges County. While it is possible that that the board footage was actually higher, the woods was certainly quite different nearly a hundred years ago. Many of todays white oaks were 150 years old, and probably pushed board footage well over 6000 feet on some acres, but few of the other trees were mature at that time. Many areas now predominantly in poplar appear to be old-field forest, and had relatively young trees, perhaps resulting from reduced agriculture after the Civil War. Such areas had little merchantable timber in 1907, and would have brought the overall average within the 2000-6000 board foot designation.
The rather low board footage of 1907 does not seem to be the result of natural causes. While pit-and-mound contours indicate the loss of mature trees to windthrow in the past, and large trees show evidence of recent lightning strikes, it appears that prior cutting and agriculture had affected the structure of the woods at that time. It is said that W. Seton Belt, the former owner, was protective of his woods, but that, in his will, he also allowed for some utilization of timber for farm repairs in the future. This suggests that cutting of farm timber was an accepted activity during his familys ownership. Also, Belt may have endorsed the concept of forestry, and removed many of the less valuable trees. Use of the more slender oaks for firewood, fences and farm construction might have contributed to the rather open woodland along the ridge and a scarcity of intermediate-sized specimens. It also would explain the presence of some multiple-trunked oaks and tuliptrees. Belt became increasingly protective in later years, but it has been more than forty years since his death, and the history of the South Woods remains elusive.
Tree Heights: Methodology
The trees measured in this study were of forty-two species, including eight naturalized taxa and several native escapes probably introduced by birds. Although the non-indigenous species might be shunned by the purist, most are likely to become a permanent part of local woodlands, and it is useful to document their presence. Maximum heights were quite varied, since some species were represented by immature specimens. The smaller trees, up to thirty feet in height, were measured directly to within one-half inch, using an adjustable aluminum pole.
The larger trees were measured with a laser, in conjunction with a clinometer. Dense foliage often made sighting difficult, and care was taken to acquire accurate measurements. The trunk circumference at breast height (CBH) was also measured. CBH was recorded to within the nearest half-inch at a point 4.5 feet above the contour passing through the center of the trees base.
Heights reflect the vertical distance between two horizontal planes, one passing through the afore-mentioned basal contour, and the second passing through the highest leaf or twig in the trees crown. The use of a laser avoided errors caused by the top point not being over the trees base, or the creation of false tops common to clinometer/fixed-baseline methods. Use of an adjustable pole established a fixed sighting point above screening vegetation, and increased accuracy by eliminating multiple triangulations.
Tall trees were selected by a quick laser reading. Once selected, more careful measurements were taken. Angles were read to within one-tenth degree, and the laser was positioned to eliminate undisplayed fractional distances. If the pole was not on the basal contour, a level was placed to that point, and a basal adjustment made. Each measurement component was recorded in the field; final heights were derived later.
Attempts were made to accurately record the location of each tree measured. Unfortunately, the dense crown coverage often blocked GPS signals, and some coordinates were not obtained. The South Woods has been marked with a grid system, which provided some fixed reference points, but many points were hidden in the understory, and some flags have been pulled up. Since it was often unknown if individual trees would prove to be the tallest of their species, more general descriptions of locations were recorded, referencing natural landmarks, in the sequence in which encountered. These field descriptions are not included in this presentation.
Although many species were represented by only a few specimens, and only the height of the highest tree is used in the height profile, the method is consistent, and provides much useful information for interpreting the effect of habitat on tree species within the South Woods. The tallest trees were usually growing under the optimum circumstances existing for that species, which prompts further consideration of such factors.
Field work was undertaken on five dates, between September 30 and November 4, 2001. It is possible that taller examples and additional species have been overlooked. If the study is incomplete, in the long term the height structure is changeable; trees grow, and some die; these measurements only reflect the structural composition of the South Woods at the present time. As presented, these measurements create a height profile that is unique to the South Woods, and should prove useful for comparison with other sites as accurate height profiles are recorded.
The following specimens were the tallest of their species seen in the South Woods. The list is divided into height groups, which correspond to general habitat requirements. It can be seen that there are few dominant species, and the rest survive by their shade tolerance, or by competing for solar access at the edge of the forest stand.
Mesic dominants: Moist rich soils.
Tuliptree Liriodendron tulipifera 159.9 12 5.5 upper swale, SW section
Northern red oak Quercus rubra 144.4 7 8.5 low slope, NE section
White oak Quercus alba 143.7 11 1.0 low slope, mid-E section
Submesic dominants: Mostly well-drained soils, ridges and south slopes.
Black oak Quercus velutina 143.4 14 2.0 broad swale, NE section
Sand hickory Carya pallida 137.4 7 7.5 small ridge, NE section
Subdominants: Height not adequately competitive, often sunlight-deprived.
Sycamore Platanus occidentalis 126.7 5 7.0 with tuliptrees, N section
Sour gum Nyssa sylvatica 124.1 6 5.5 broad swale, NE section
Sweet gum Liquidambar styraciflua 118.1 6 3.5 broad swale, NE section
Black walnut Juglans nigra 111.4 5 11.5 with tuliptrees, N section
Pignut Carya glabra 98.5 3 7.5 broad rich swale, NE section
Red maple Acer rubrum 88.4 4 9.5 opening, bottom, SW section
Bitternut Carya cordiformis 64.3 3 0 end of ridge, SW section
Forest/field and roadside interfaces:
Southern red oak Quercus falcata 100.6 6 5.5 old border, N section
Mazzard cherry Prunus avium (naturalized) 89.2 6 4.0 old edge, NW section
Bigtooth aspen Populus grandidentata 80.6 4 10.0 S slope, border SE section
American elm Ulmus americana 73.4 9 3.5 edge, S section
Black locust Robinia pseudoacacia 71.5 3 2.0 old edge, NW section
River birch Betula nigra 68.4 4 5.5 edge utiity r/w, SW section
Paulownia Paulownia tomentosa (natd) 46.8 3 1.0 open bottom, SW section
Hackberry Celtis occidentalis 44.8 2 5.5 dry bank, S edge
Sassafras Sassafras albidum 42.0 2 6.0 old edge, NW section
Bradford pear Pyrus calleryana (natd) 40.7 0 10.0 slope with tuliptrees, N section
Willow oak Quercus phellos 36.6 4 6.0 dry bank, S edge
Black cherry Prunus serotina 32.2 1 4.5 top of road bank, NE section
Red mulberry Morus rubra 29.3 1 2.5 edge, mid-S section
Mimosa Albizzia julibrissin (natd) 24.3 1 9.0 road bank, mid-E section
Silver maple Acer saccharinum 19.9 0 10.0 edge, S section
Eastern redcedar Juniperus virginiana 17.0 0 8.0 top road bank, NE section
Ailanthus Ailanthus altissima (natd) 14.1 0 8.5 S edge, SW section
Peach Prunus amygdalus (natd) 8.3 - roadside, SE section
Understory species: Shade-tolerant.
American beech Fagus grandifolia 62.1 1 11.5 mesic ridge, SE section
Norway maple Acer platanoides (natd) 59.3 1 11.5 near mesic edge, SE section
Ironwood Carpinus caroliniana 48.5 2 5.0 moist bottom, SW section
Fl. dogwood Cornus florida 38.2 2 0 low open slope, NW section
American chestnut Castanea dentata 34.4 0 11.0 low slope, SW section
Boxelder Acer negundo 27.8 0 9.0 slope with tuliptrees, N section
American holly Ilex opaca 25.3 1 4.5 swale, SW section
Pawpaw Asimina triloba 21.6 0 7.5 shady swale, mid-E section
Black haw Viburnum prunifolium 19.1 1 3.0 with tuliptrees, N section
Crape myrtle Lagerstroemia indica * 17.1 0 5.0 mesic opening, N end ridge
Spicebush Lindera benzoin 15.3 0 4.5 mesic opening, NE section
White pine Pinus strobus (escape) 7.4 - bank, old border, NE section
* tentative identification (escape)
At least five species set new state or national height records. The tallest tuliptree in the South Woods measured 159.9 feet, and another 159.6. These are the tallest trees of any species accurately measured in Maryland, surpassing a 157.6-foot tuliptree measured in the spring of 2000 at Chase Creek Woods, in Anne Arundel County. They also exceed an unconfirmed historic Maryland record: a white pine near the Savage River in Garrett County is said to have measured 159 feet tall (Besley, 1938). Among eastern hardwoods, only trees in the Southern Appalachians are known to be taller; tuliptree has been accurately measured to 175.5 feet, and one white ash reached 163 feet. Five other tuliptrees in the South Woods exceeded 150 feet. These specimens are still growing rapidly, but significant increases in height may be limited by divergence of the upper crown.
The tallest white oak was 143.7 feet. This is the tallest white oak accurately measured in Maryland, and easily exceeds a 118.0-foot specimen at Chase Creek Woods. It is surpassed by a 147.6-foot specimen in the Great Smoky Mountains National Park. Many historic records have been in error. The Maryland Forest Service listed a 149-foot Anne Arundel County white oak in 1990, but recent laser measurements showed it to be 104.5 feet. A Calvert County white oak listed by the Maryland Forest Service as 158 feet in 2001 was remeasured at 92 feet.
Northern red oak was less abundant, but many large specimens with broad crowns exist, especially on the ridge, where heights were unremarkable. A specimen on a rich swale in the northeast section reached a height of 144.4 feet, which is the tallest accurately measured in Maryland, exceeding a 135.5-foot specimen at Chase Creek Woods. It is second only to a 152.9-foot specimen discovered near the Whitewater River, in South Carolina, in January 2004.
Old black oaks were frequent, especially on the central ridge. A very large specimen in a mesic swale was also the tallest, with a height of 143.4 feet, which is the tallest reported in the eastern United States. In Maryland, it exceeds a 135.6-foot specimen at Chase Creek Woods, and an unconfirmed 140-foot Baltimore County specimen listed by the state in 2001.
Sour gums were rather shade-tolerant, and occupied an important subdominant position. One specimen was 124.1 feet in height, which appears to be the tallest accurately measured, exceeding a record of 121.0 feet in the Great Smoky Mountains National Park.
Although few of the hickories approached the 137.4-foot height of the tallest specimen, bark contours suggest that most are quite old. Sweet gum, black walnut and sycamore reached heights over 110 feet, but were not height-competitive with tuliptree. Most examples were sunlight-deprived; therefore, these species were not present in sufficient numbers to appreciably affect the overall structure of the stand.
A correlation between record heights and optimum habitat was noted. Certain indicator plants were often in the immediate vicinity of exceptional specimens. Useful examples were Collinsonia, broad beechfern, maidenhair fern, and glade fern. These were not abundant, but occurred with the tallest tuliptrees, northern red oak, black oak, beech and spicebush. These species, especially glade fern, which is rare in Maryland, also occur with the tallest tuliptrees and tallest northern red oak on similar soils at Chase Creek Woods, in Anne Arundel County.
Structurally, the South Woods is an old stand of unusually tall trees gradually acquiring characteristics associated with old-growth. Pit-and-mound contours, lightning injury, dead snags and large fallen trunks are frequent. Many black oaks are senescent, with frequent dieback, but the white oaks, northern red oaks and tuliptrees show fewer infirmities. Hollow, senescent, or oversized specimens of the latter species were seldom encountered. In many areas, the canopies appear to be height-segregated by species of rather uniform height and, perhaps, age. The north and northeast sections are dominated by tuliptree, probably of old-field origin. Here, and in the central and southeast sections, there are few submature examples of the larger species. Various factors, including the longevity of the essentially continuous upper canopy, prevalence of tuliptree, and the density of the dogwood/spicebush understory, seem to have contributed to this situation. The few windthrow openings receive but limited sunlight, remain dominated by the understory, or become affected by the growth of riverbank grape, Vitis riparia. The southwest section, in some ways less spectacular, is more typical of steady-state old growth; windthrow is much more frequent on the heavier soils, diversity is greater, and more specimens of different age classes are present.
Due to the longevity of the taller species, the overall structure of the South Woods is quite stable, but some changes may be expected. The diversity of tree species along the perimeter borders will gradually be diminished by the rapid growth of an adjoining old-field forest to the north and northwest, and the prevalence of young hickories in the roadside thickets at Church Road. Continuing loss of flowering dogwoods to anthracnose will affect the structure of the understory. Pawpaw may be expected to spread vegetatively. American beech will increase in height, creating an intermediate canopy. Ailanthus may become a problem if not controlled, but the other naturalized tree species should remain of infrequent occurrence. Invasive vines and plants are of concern, especially Celastrus orbiculatus, Euonymus fortunei, Hedera helix, Rosa multiflora and Polygonum perfoliatum. These will spread beyond control and cause serious damage if not quickly eliminated.
There is evidence suggesting that farm activities, including the abandonment of open land and some selective logging, have played an important role in the existing forest structure. This is but one viewpoint; it is likely that there will be varied opinions regarding the South Woods, which should guarantee continuing interest and study. Despite its limited diversity of habitat, the South Woods is complex, and illustrates the many ways in which a forest reacts to the activities of man, and the undeniable influence of exceptional soils and time in allowing individual trees to reach their full height potential.
The author wishes to express his appreciation to several individuals who have made this study possible. First, I am indebted to Mrs. Pamela Cooper of the Western Shore Conservancy, who graciously provided access into the South Woods preserve. Mrs. Coopers continuing stewardship has been instrumental in protecting this irreplaceable site.
The assistance of Mr. Wayne Longbottom was important in locating numerous additional plants, including indicator species that were valuable in establishing a correlation between tree heights and habitat. A plant list assembled by Mr. Longbottom has been incorporated in Appendix B.
My appreciation is also extended to Mr. Robert T. Leverett of Holyoke, Massachusetts, who has been a leader in refining methods for the accurate measurement of tree heights, and provided important height data through the Eastern Native Tree Society.
Appendix A: Comments on Heights of Individual Species
Tuliptree: Tuliptree was common throughout, especially in the north and northeast sections. While few specimens maintained a central leader above 100 feet, many exceeded 10 CBH, and heights over 140 were not unusual. Most exhibited a rather uniform bark pattern, and were probably 120-140 years old. Some trees in the southwest and northeast sections appeared to be contemporary with the white oaks; one at the northern boundary measured 14 8 CBH and 131.3 tall. Seven trees were over 150 feet. The tallest tuliptree was at the head of a broad swale in the southwest section; competition between its two upper leaders promoted a height of 159.9; CBH was 12 5.5. The second tallest example was located on the west slope, above a glade fern site in the southwest section, and was 159.6 tall with a CBH of 10 7.5. A tree beside a white oak log in the northeast section was the third tallest at 153.7; it also had a CBH of 10 7.5. In the northernmost portion, the more dominant of a pair of old trees was the fourth tallest, with a height of 152.9 and a CBH of 12 2. The fifth tallest, at 152.5, had a CBH of 11 2, and was located below a glade fern site in the southeast section. The sixth tallest measured 152.3, and was located in a swale on the west side of the ridge, below the second-tallest tree. This tree is quite old, and the base is weakened by decay on the northwest side. The trunk measured 15 9 CBH, which is the largest of any tree in the South Woods. A tree north of a tall sycamore in the northeast section was seventh at 152.1 tall, with a CBH of 12 5.
Northern red oak: Although heights were not remarkable on the drier soils along the ridge, large examples occurred throughout the stand. A handsome specimen was seen in the northwest boundary. Another, in the northeast section, had a broad crown, measured 12 11 CBH and 134.0 in height. A more slender specimen in the northeast section was taller, being 144.4 in height; CBH was 7 8.5. This tree was at a low elevation with spicebush, Collinsonia and tuliptree. A nearby large double-trunked specimen of similar height has fallen recently.
White oak: This species is the oldest component of the South Woods. Numerous old specimens were seen. The crowns were usually quite irregular. Most of the white oaks are of similar dimensions; it appears that competition has deterred the development of trees with broad symmetrical crowns or unusually thick trunks. One of the largest was 11 1 CBH, and was the tallest, at 143.7. This tree maintained a central leader, and was located at a low elevation off Church Road, south of the pawpaw site. The presence of Collinsonia indicates cool moist soils of high fertility.
Black oak: Black oak was an important forest component, but seldom height-competitive, except along borders, and on the driest sites, especially the central ridge and south slope, where it was a frequent co-dominant. Many specimens were quite old, with an accumulation of outer bark being shed, leaving a rather uniform light-gray surface. The crowns were often heavy-limbed, and quite irregular, limiting height increase, but their breadth assured solar access despite the proximity of taller tuliptrees. A large specimen on dry soil in the south section was 10 3 CBH, and 117 feet tall. Large examples also occurred in the southwest section, where one measured 135.3 tall, with a CBH of 9 6.5. The most impressive was a straight-trunked specimen in a broad swale on the northeast side of the central ridge, with broad beechfern. CBH was 14 2, height was 143.4.
Sand hickory: Examples of this species occurred throughout, and were somewhat height-competitive on the drier soils of ridges and upper slopes. The globose fruit and seven narrow leaflets provided tentative identification, but a more careful examination should be conducted. The tallest measured was on a small ridge aligned with the high point of Church Road in the northeast section. Height was 137.4, CBH 7 7.5.
Sycamore: But two specimens were seen, both in the northeast section, and probably of old-field origin, with tuliptree. CBH of the taller was 5 7, height 126.7. Height was barely competitive; the other, to the east, with sweet gum, has been overtopped by tuliptree.
Sour gum: Examples of all sizes were found in most areas, particularly the upper portions of the central ridge. A specimen at the north end of the Church Road border had a CBH of 7 8. Most heights were not remarkable, and all specimens were at a severe height disadvantage. The tallest were in swales in the northeast section, with tuliptree. One slender specimen, which was shedding its outer bark, had a CBH of 5 4 and a height of 112.8. The largest, not far from the northeast woods boundary, was 6 5.5 CBH and 124.1 tall.
Sweet gum: A few specimens were seen with tuliptrees off Church Road. The largest were near the woods boundary in the northeast section; one measured 6 3.5 CBH and 118.1 tall, but was not height-competitive with nearby tuliptrees.
Black walnut: Four examples of similar diameter were found with spicebush and tuliptree in the northeast section. All were at a height disadvantage, and had limited access to sunlight. The tallest was 111.4, with a CBH of 5 11.5.
Southern red oak: One specimen of this familiar coastal-plain species was seen on an upper slope in an old west-facing border in the north section. Although the prevalence of greenbrier suggested wetter soils than usual for the species, the warm sunny exposure was typical. Height was 100.6 feet; CBH was 6 5.5.
Pignut hickory: This species appears to be of infrequent occurrence, and may be expected on the more mesic sites. The necked fruit provides identification. A specimen in the southwest section was 97.5 tall. A slender example on a rich swale above the largest black oak was taller, at 98.5. CBH was 3 7.5
Mazzard cherry: Few specimens were seen. An old example of this naturalized species remains in the old northwest border, where it is somewhat height-competitive. Height was 89.2, CBH 6 4.
Red maple: This species occurs on low ground in the southwest section. Although rather shade-tolerant, this species was absent from most interior areas. A few specimens were seen in the northwest border. The largest specimen was found in the southwest section; height was 88.4; CBH measured 4 9.5.
Bigtooth aspen: But one specimen was seen, on a natural south-facing border slope in the southeast section. Height was 80.6; CBH was 4 10.
American elm: This species is common in the borders facing Central Avenue, and occasional in windthrow openings. The largest specimens were along a utility right-of-way, in the south section. The only old example was seen here; this shapely tree had a 9 3.5 CBH, and a height of 73.4
Black locust: This intolerant species was common with tuliptrees in comparatively recent old-field growth beyond the northwest border, but infrequent in the South Woods borders. Some occur in an old-field area that forms an extension of the southwest section, and a few near the utility right-of-way. A double-trunked specimen in the old northwest border was 71.5 tall; the larger stem was 3 2 CBH.
River birch: A few specimens occur in the open woods with remnants of the old northwest border, at its interface with an old-field growth of young tuliptrees. One measured 57.0 feet. This species was more frequent in the south-facing border in the southwest section, where one old tree was seen. The tallest was 68.4, with a CBH of 4 5.5.
Bitternut hickory: Mature trees were much less common than sand hickory, but small examples were frequently seen. The unique bud served for identification. The tallest measured was on a slope at the south end of the ridge, in the southwest section; CBH was 3 0, height 64.3. Taller examples may occur.
American beech: Smaller specimens were frequently seen in the thick understory, especially on the east side of the main ridge. Continued growth of these trees will create a mid-level canopy, intermediate between the dogwoods and hickories. The largest example, with a CBH of 3 11.5, and a 56.2 foot height, stands between two very large tuliptrees near an old border in the north section. A taller, but more slender specimen was found on a low ridge with glade fern and Heuchera in the northeast section; CBH was 1 11.5; height was 62.1.
Norway maple: Several specimens of this non-native tree were seen. The largest, found at a glade fern station near Church Road, was 59.3 in height, with a CBH of 1 11.5. A smaller specimen was seen near another glade fern site, on the southwest side of the main ridge.
American hornbeam (ironwood): Examples were common, especially on the lower elevations. This species contributed to the dense understory, with spicebush and flowering dogwood. The largest trees were on a silty lowland in the southwest section. One measured 2 5.0 CBH and 48.5 tall.
Paulownia: Several examples were seen in windthrow openings on a fertile lowland in the southwest section. The tallest was 46.8, with a CBH of 3 1.
Hackberry: This species is usually associated with neutral or alkaline soils. Several small specimens were seen in the understory. A larger example, on a steep dry bank on the south border, was 44.8 tall and 2 5.5 CBH.
Sassafras: This species is infrequent throughout, with the largest examples remaining with remnants of the northwest border. Although sassafras is somewhat shade tolerant, the adjoining old-field forest is rapidly obstructing sunlight necessary for the survival of these trees. Maximum height was 42.0, CBH was 2 6.
Bradford pear: This ornamental species is rapidly becoming naturalized. Several specimens were seen. The largest was in the north section; it measured 10 CBH and 40.7 tall.
Flowering dogwood: A numerous and important component of the understory, dogwoods were most plentiful on upper slopes and ridges, but also occurred with spicebush on lower elevations. Many specimens have been killed by anthracnose. Large examples are no longer common; the maximum seen was 2 0 CBH and 38.2 tall.
Willow oak: Several small specimens less than four feet tall were seen near the northwest border. Several willow oaks have been planted at a subdivision across Church Road. The small acorns of these trees may be distributed by birds. The only mature example was found on a steep bank at the southern boundary. This bank may have formed the roadside of the original Central Avenue. The low stature of this tree was probably due to the dry situation. CBH was 4 6; height was 36.6.
American chestnut: One specimen was seen near the base of a steep west-facing slope, near a large tuliptree, at the southwest end of the central ridge. Height was 34.4, CBH 11.
Black cherry: Only a few small specimens were seen. All were in sunny border situations. One at Church Road, in the northeast section, was 32.2, CBH 1 4.5. The essential absence of black cherry was unexpected, since this familiar species is distributed by birds and young trees are somewhat shade-tolerant.
Red mulberry: Associated with rich soils, perhaps ten immature examples were seen within 50 yards of Church Road, roughly 100 yards from Route 214. Another was in the southeast corner. The largest specimen was in the south border; it had a height of 29.3 and a CBH of 1 2.5. This species has been greatly reduced by disease elsewhere, and mature specimens are rare.
Boxelder: Occasional small specimens were seen, especially on low elevations in the southwest section. A slightly larger example was found on a slope with large tuliptrees in the northern section. Height was 27.8, CBH 0 9.
American holly: Several small specimens occur in the more open woods on the ridge. A mature specimen, on the northeast side, was 24.5 tall, with a 1 4 CBH.
A slightly larger tree was found in a swale in the southwest section. Height was 25.3; CBH was 1 4.5
Mimosa: One specimen of this naturalized tree was seen at the top of a steep bank on Church Road. Height was 24.3, CBH was 1 9.
Pawpaw: This species was seen at perhaps ten locations. Most occurrences consisted of a dozen or less sub-arborescent specimens. A large patch of young trees was seen in a swale perhaps 200 off Church Road. The largest was 21.6 tall. Probably recently introduced by wildlife, this species may be expected to spread vegetatively.
Silver maple: One specimen of this native species was seen in the south border. It is not considered indigenous to the site, and the source is unknown. Height was 19.9; CBH was 10.
Blackhaw: Small examples were frequent on mid-slopes, but few reached tree stature. The two largest were near black walnuts in the northeast section. Maximum height was 19.1, CBH was 1 3.
Crape myrtle: This is a very tentative identification of two vigorous young upright trees with compound leaves of 7-15 entire glabrous leaflets. The tips are abruptly acuminate, and the bases round-tapering to a very short petiole. The bark is red-brown, as is the rachis. The foliage was still green on November 4. Height was 17.1, CBH 5.
Eastern redcedar: The side-branching structure of the perimeter thickets provides few niches for this upright species. A young specimen, 17.0 tall, was seen in the open woods above a steep bank on Church Road.
Spicebush: Although forming a continuous low canopy on rich moist soils in the northeast section, and common on the lower slopes facing Church Road in the southeast, few specimens of arborescent stature were seen. The maximum height measured was 15.3.
Ailanthus: Two small examples of this naturalized species occur in a sunny edge paralleling Central Avenue. Height was 14.1, CBH 8.5. This species will likely spread by root-sprouts.
Peach: Several young examples of this somewhat naturalized species occur at the southernmost edge along Church Road. The source of these trees is unknown. Maximum height was 8.3.
White pine: One specimen, an escape of unknown origin, was seen by a barbed-wire fence at the north end of the Church Road boundary. Height was 7.4 feet.
Although many herbaceous species, such as mayapple, were no longer visible in October, the following plants shared habitats with various tree species. Some were represented by only a few specimens, but many were useful indicators of soil characteristics, and the overall effect of elevation, exposure and other habitat characteristics. Attention to plant distribution was valuable in locating and interpreting optimum habitat for each tree species. The typical habitat is given, and conforms well to the Belt Woods sightings.
Berberis thunbergii Japanese barberry (natd) Rich moist low open woods
Corylus americana American hazelnut Rich moist open woods
Euonymus alatus Winged euonymus (natd) Moist open woods
Euonymus alatus var. apterus Smooth euonymus (natd) Moist open woods
Ilex verticillata Whorled winterberry Swamps and wet swales
Ligustrum vulgare Privet (natd) Low wet woods
Rosa multiflora Multiflora rose (natd) Moist open woods and edges
Rubus occidentalis Black raspberry Edges and woodland openings
Rubus phoenicolasius Wineberry (natd) Rich moist edges & openings
Vaccinium vacillans Early low blueberry Dry open acidic woods
Viburnum acerifolium Maple-leaved viburnum Rich dry sandy woods
Viburnum dentatum Southern arrowwood Low rich sandy soils
Amphicarpa bracteata Hog peanut Moist rich low woodlands
Celastrus orbiculatus Asian bittersweet (natd) Woodland borders, openings
Euonymus fortunei Wintercreeper euon. (natd) Moist rich open woodlands
Hedera helix English ivy (natd) Moist woodlands
Lonicera japonica Japanese honeysuckle (natd) Moist woods and borders
Parthenocissus quinquefolia Virginia creeper Woodland borders
Passiflora lutea Yellow passionflower Rich moist woodland borders
Rhus radicans Poison ivy Moist woodlands and borders
Smilax glauca Glaucous greenbrier Dry sandy open woods
Smilax rotundifolia Common greenbrier Wet woodlands and edges
Vitis riparia Riverbank grape Moist woodland borders
Adiantum pedatum Maidenhair fern Moist rich shady woods
Asplenium platyneuron Ebony spleenwort Rich dry rocky woods
Athyrium felix-femina Lady fern Rich shady moist woods
Botrichium dissectum Common grape fern Low rich woods
Botrychium virginianum Rattlesnake fern Rich deciduous woods
Diplazium pycnocarpon Glade fern Rich moist neutral shady woods
Onoclea sensibilis Sensitive fern Moist rich woodland openings
Polystichum acrostichoides Christmas fern Shady woodland slopes
Thelypteris hexagonaptera Broad beechfern Rich shady deciduous woods
Thelypteris noveboracensis New York fern Moist thickets in low woods
Other herbaceous plants:
Aplectrum hyemale Putty-root Rich low hardwood forests
Arisaema triphyllum Jack-in-the-pulpit Rich moist woods
Chimaphila maculata Spotted wintergreen Dry rich acidic forests
Cimicifuga racemosa Black snakeroot Rich open deciduous woods
Cinna arundinacea Wood reedgrass Moist woods and swamps
Circaea quadrisulcata Enchanters nightshade Moist rich forests and ravines
Collinsonia canadensis Richweed Rich moist woods and ravines
Desmodium nudiflorum Naked-flowered tick trefoil Dry rich deciduous woods
Dioscorea quaternata Whorled wild yam Rich moist open woods
Dioscorea villosa Wild yam Wet open woods
Duchesnea indica Indian strawberry (natd) Moist fields and open woods
Galium aparine Bedstraw (natd) Moist open woods and edges
Geum canadense White avens Woodland borders
Phytolacca americana Pokeweed Low grounds and rich soil
Pilea pumila Clearweed Cool moist shaded places
Polygonatum biflorum Solomons seal Woods and thickets
Polygonum perfoliatum Perfoliate tearthumb Wet borders and openings
Sanguinaria canadensis Bloodroot Rich open woods
Scutellaria integrifolia Larger skullcap Dry to moist open woods
Heuchera americana Common alumroot Rich woodland slopes
Tipularia discolor Cranefly orchid Rich, sandy deciduous woods
Tovara virginiana Virginia knotweed Rich woods and thickets
Uvularia perfoliata Perfoliate bellwort Moist woods
Verbena urticifolia White vervain Rich woodland borders