**4. Chemistry of water from HEAs and seeps**

Studies of oil and gas wells generally, as well as for those located across the Trenton Formation, revealed brine is readily evident and the chemistry reflects local limestone composition [19, 20, 35]. Hence, wells within a short distance can show variations in concentrations of key elements. General features of brine within the Trenton Formation describe this water as having a near neutral pH (5.5–7.0) with elevated concentrations of elements that can be described generally as follows: Cl >100,000 mg/L, Na >50,000 mg/L, Ca > 20,000 mg/L, Sr. > 5000 mg/L, Mg >2000 mg/L, K > 2000 mg/L, Ba >2000 mg/L, Bo >1000 mg/L, SO4 –2 > 500 mg/L, and Fe > 300 mg/L [19, 35]. This general composition of brine represents concentrations of elements that are potentially harmful to aquatic and terrestrial life and why this water is regulated under Ontario's *Oil, Gas and Salt Resources Act*. This need to control the release of brine can be illustrated by considering the Cl surface water quality guideline in Canada to protect aquatic life during short-term exposure is 640 mg/L and long-term exposure is 120 mg/L [36] while brine may contain Cl at >100,000 mg/L. Thus, water from HEAs can be regarded as hazardous to plants and wildlife, even in small quantities. Water samples collected by WUT confirmed the presence of brine at HEAs.

## **5. Results**

Integration of available information from WUT, scientific literature, and field inspections allowed for the identification of a list of plants associated with HEAs in field and forest habitats (**Tables 2–4**). The first forest habitat type is dominated by balsam poplar (*Populus balsamifera* L.) and the second forest habitat dominated by balsam fir (*Abies balsamea* L.) and eastern white cedar (*Thuja occidentalis* L.). When the plant associations with HEAs were identified, they were intended to represent spatial patterns concerning the general plant community found in each area, as


**111**

**Table 2.**

*poplar [25].*

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

**Plants within 5 m** 

**Plants within 1 m of** 

**HEA**

**A B C D A B C D**

**of HEA**

well as the plant species tolerant of these habitats, within ~5 m and within 1 m of an HEA. These community associations show how diverse plant communities become depauperate with increased proximity to the HEAs and how EPI is consistently the

*Representation of common plant species found at different distances from HEAs in forests dominated by balsam* 

*These settings included site A with wood crib, site B with pipe that was bubbling natural gas, site C with pipe draining* 

Using Ontario's Ecological Land Classification (ELC) strategy [37] and the lists of common plants associated with the HEAs (**Tables 2**–**4**), the ecosites associated

most common species within 1 m of HEAs.

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

Northern bugleweed (*Lycopus uniflorus* Michx.)

Quaking aspen (*Populus tremuloides* Michx.)

Rough bedstraw (*Galium asprellum* Michx.) Sensitive fern (*Onoclea sensibilis* L.) Silver maple (*Acer saccharinum* L.)

Spotted joe-pye weed (*Eutrochium maculatum* L.)

Sweet white clover (*Melilotus officinalis* L.) Sugar maple (*Acer saccharum* Marshall)

White trillium *(Trillium grandiflorum* Michx.)

Yellow daylily (*Hemerocallis lilioasphodelus* L.)

Staghorn sumac (*Rhus typhina* L.) St. John's wort (*Hypericum perforatum* L.)

Tamarack (*Larix laricina* Du Roi)

White oak (*Quercus alba* L.) White spruce (*Picea glauca* Moench)

Yellow sedge (*Carex flava* L.)

Red osier dogwood (*Cornus sericea* L.)

Northern red oak (*Quercus rubra* L.)

**HEA**

**Plants found in poplar forest settings within 30 m of** 

Orange daylily (*Hemerocallis fulva* L.) X

New England aster (*Symphyotrichum novae-angliae* L.) X X

Ostrich fern (*Matteuccia struthiopteris* L.) X X

Smooth Solomon's seal (*Polygonatum biflorum* Walter) X Spotted jewelweed (*Impatiens capensis* Meerb.) X X X X

Stinging nettle (*Urtica dioica* L.) X X

Tall buttercup (*Ranunculus acris* L.) X

White ash (*Fraxinus americana* L.) X

Wild carrot (*Daucus carota* L.) X X X X

Yellow hawkweed *(Hieracium piloselloides* Vill.) X X

*water to long drainage channel, and site D representing a dry pipe in a forest.*

Virginia strawberry (*Fragaria virginiana* Duchesne) X X X X X

White birch (*Betula papyrifera* Marshall) X X X

Red maple (*Acer rubrum* L.) X X

Riverbank grape (*Vitis riparia* Michx.) X X X X X


*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*

*These settings included site A with wood crib, site B with pipe that was bubbling natural gas, site C with pipe draining water to long drainage channel, and site D representing a dry pipe in a forest.*

### **Table 2.**

*Plant Communities and Their Environment*

Arctic sweet coltsfoot (*Petasites frigidus* L.)

Bebb's sedge (*Carex bebbii* Olney ex Fernald)

Blue-joint (*Calamagrostis canadensis* Michx.) Bur oak (*Quercus macrocarpa* Michx.)

Common ragweed (*Ambrosia artemisiifolia* L.) Common evening primrose (*Oenothera biennis* L.) Common lady fern (*Athyrium filix-femina* L.) Common milkweed (*Asclepias syriaca* L.) Common mullein (*Verbascum thapsus* L.)

Common yarrow (*Achillea millefolium* L.) Daisy fleabane (*Erigeron annuus* L.)

Eastern bracken fern (*Pteridium aquilinum* L.)

Eastern white cedar (*Thuja occidentalis* L.) False Solomon's seal (*Maianthemum racemosum* L.) Green ash (*Fraxinus pennsylvanica* Marshall)

Heal-all (*Prunella vulgaris* L.)

Lesser burdock (*Arctium minus* Bernh.)

Multiflora rose (*Rosa multiflora* Thunb.)

Longroot smartweed (*Polygonum coccineum* Muhl. ex

Eastern cottonwood (*Populus deltoides* W. Bartram ex Marshall)

Black cherry (*Prunus serotina* Ehrh.)

Canada thistle (*Cirsium arvense* L.) Cinnamon fern (*Osmunda cinnamomea* L.)

**HEA**

**Plants found in poplar forest settings within 30 m of** 

Apple (*Malus domestica* Borkh.) X X X X

Black ash (*Fraxinus nigra* Marshall) X X X X

Black medic (*Medicago lupulina* L.) X X Black spruce (*Picea mariana* Mill.) X

Canada goldenrod (*Solidago canadensis* L.) X X X X

Common raspberry (*Rubus arcticus* L.) X X X X

Ground juniper (*Juniperus communis* L.) X

Golden sedge (*Carex aurea* Nutt.) X X

Mapleleaf viburnum (*Viburnum acerifolium* L.) X X X Marginal wood fern (*Dryopteris marginalis* L.) X

Eastern poison ivy (*Toxicodendron radicans* L.) X X X X X

Marsh horsetail (*Equisetum palustre* L.) X X X X

Chestnut sedge (*Carex castanea* Wahlenb.) X Columbine (*Aquilegia canadensis* L.) X Common buckthorn (*Rhamnus cathartica* L.) X Common dandelion (*Taraxacum officinale* Ledeb.) X X X X

Balsam poplar (*Populus balsamifera* L.) X X X X X X X Balsam fir (*Abies balsamea* L.) X X X

**Plants within 5 m** 

**Plants within 1 m of** 

**HEA**

**A B C D A B C D**

**of HEA**

**110**

Willd.)

*Representation of common plant species found at different distances from HEAs in forests dominated by balsam poplar [25].*

well as the plant species tolerant of these habitats, within ~5 m and within 1 m of an HEA. These community associations show how diverse plant communities become depauperate with increased proximity to the HEAs and how EPI is consistently the most common species within 1 m of HEAs.

Using Ontario's Ecological Land Classification (ELC) strategy [37] and the lists of common plants associated with the HEAs (**Tables 2**–**4**), the ecosites associated


**113**

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

Mapleleaf viburnum (*Viburnum acerifolium* L.) X X X

Red maple (*Acer rubrum* L.) X X X X

**Plants within 5 m** 

**Plants within 1 m** 

**of HEA**

**E F E F**

**of HEA**

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

Northern maidenhair fern (*Adiantum pedatum* L.)

New England aster (*Symphyotrichum novae-angliae* L.) Northern bugleweed (*Lycopus uniflorus* Michx.)

Northern maidenhair (*Adiantum pedatum* L.) X X

Riverbank grape (*Vitis riparia* Michx.) X X

Spotted jewelweed (*Impatiens capensis* Meerb.) X X

Virginia strawberry (*Fragaria virginiana* Duchesne) X X X

White birch (*Betula papyrifera* Marshall) X X X

Yellow birch (*Betula alleghaniensis* Britton) X X

Sugar maple (*Acer saccharum* Marshall) X

Marginal wood fern (*Dryopteris marginalis* L.) Marsh horsetail (*Equisetum palustre* L.) Multiflora rose (*Rosa multiflora* Thunb.)

Northern red oak (*Quercus rubra* L.) Orange daylily (*Hemerocallis fulva* L.) Ostrich fern (*Matteuccia struthiopteris* L.) Pussy willow (*Salix discolor* Muhlenb.) Quaking aspen (*Populus tremuloides* Michx.)

Red osier dogwood (*Cornus sericea* L.) Red spruce (*Picea rubens* Sarg.)

Rough bedstraw (*Galium asprellum* Michx.) Sensitive fern (*Onoclea sensibilis* L.) Shining willow (*Salix lucida* Muhlenb.) Silver maple (*Acer saccharinum* L.)

Smooth Solomon's seal (*Polygonatum biflorum* Walter)

Spotted joe-pye weed (*Eutrochium maculatum* L.) St. John's wort (*Hypericum perforatum* L.)

Western bracken fern (*Pteridium aquilinum* L*.* Kuhn)

Stinging nettle (*Urtica dioica* L.)

Tall buttercup (*Ranunculus acris* L.) Tamarack (*Larix laricina* Du Roi)

White ash (*Fraxinus americana* L.)

White spruce (*Picea glauca* Moench)

Wild carrot (*Daucus carota* L.)

White trillium *(Trillium grandiflorum* Michx.)

Yellow daylily (*Hemerocallis lilioasphodelus* L.)

Sweet white clover (*Melilotus officinalis* L.)

**of HEA**

**Plants found in white cedar-balsam Fir forest within 100 m** 

Longroot smartweed (*Polygonum coccineum* Muhl. ex Willd.)


*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*

*Plant Communities and Their Environment*

American basswood (*Tilia americana* L.)

Arctic sweet coltsfoot (Pe*tasites frigidus* L.)

Bebb's sedge (*Carex bebbii* Olney ex Fernald) Bebb's willow (*Salix bebbiana* Sarg.)

Blue-joint (*Calamagrostis canadensis* Michx.)

Common ragweed (*Ambrosia artemisiifolia* L.)

Common milkweed (*Asclepias syriaca* L.) Common mullein (*Verbascum thapsus* L.)

Common yarrow (*Achillea millefolium* L.) Daisy fleabane (*Erigeron annuus* L.)

Green ash (*Fraxinus pennsylvanica* Marshall)

Hoary willow (*Salix candida* Flügge ex Willd.) Large-toothed aspen (*Populus grandidentata* Michaux)

Lesser burdock (*Arctium minus* Bernh.)

Golden sedge (*Carex aurea* Nutt.) Heal-all (*Prunella vulgaris* L.)

Black cherry (*Prunus serotina* Ehrh.) Black medic (*Medicago lupulina* L.) Black raspberry (*Rubus occidentalis* L.) Black spruce (*Picea mariana* Mill.)

Canada thistle (*Cirsium arvense* L.) Cinnamon fern (*Osmunda cinnamomea* L.) Chestnut sedge (*Carex castanea* Wahlenb.) Columbine (*Aquilegia canadensis* L.) Common buckthorn (*Rhamnus cathartica* L.)

Apple (*Malus domestica* L.)

**of HEA**

**Plants found in white cedar-balsam Fir forest within 100 m** 

**Plants within 5 m** 

**Plants within 1 m** 

**of HEA**

**E F E F**

**of HEA**

Balsam poplar (*Populus balsamifera* L.) X X X X Balsam fir (*Abies balsamea* L.) X X X X

Black ash (*Fraxinus nigra* Marshall) X X

Common dandelion (*Taraxacum officinale* Ledeb.) X X

Common lady fern (*Athyrium filix-femina* L.) X X

Common raspberry (*Rubus arcticus* L.) X X

Eastern white cedar (*Thuja occidentalis* L.) X X False Solomon's seal (*Maianthemum racemosum* L.) X X

Ground juniper (*Juniperus communis* L.) X X

Eastern bracken fern (*Pteridium aquilinum* L.) X X X X

Eastern poison ivy (*Toxicodendron radicans* L.) X X

Canada goldenrod (*Solidago canadensis* L.) X

Common evening primrose (*Oenothera biennis* L.) X

Eastern cottonwood (*Populus deltoides* W. Bartram ex Marshall)

**112**


**Table 3.**

*Representation of common plant species found at different distances from HEAs in forests dominated by eastern white cedar-balsam fir forest along the shoreline of Cape Smith [25].*


**115**

**Table 4.**

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

Red osier dogwood (*Cornus sericea* L.) X X X

Riverbank grape (*Vitis riparia* Michx.) X X X X X X

X

**Plants within 5 m of HEA Plants within 1 m of** 

**H I J K L H I J K L**

**HEA**

with HEAs at WUT were identified. This included forest dominated by balsam poplar reflecting past forest clearing efforts during the hydrocarbon extraction period of the late 1800s. These forest areas now represent Fresh-Moist Poplar Deciduous Forest (FOD8-1) with balsam poplar as the dominant species. Other tree species include conifers such as eastern white cedar, balsam fir, white spruce (*Picea glauca* Moench), black spruce (*P. mariana* Mill.), and red spruce (*P. rubens* Sarg.). Deciduous species include American basswood (*Tilia americana* L.), American elm (*Ulmus Americana* L.), black cherry (*Prunus serotina* Ehrh.), red maple, red oak, staghorn sumac (*Rhus typhina* L.), sugar maple (*A. saccharum* Marshall), tamarack (*Larix laricina* Du Roi), white birch (*Betula papyrifera* Marshall), and white oak (*Q. alba* L.); ash species included black ash predominantly in wetlands along with green ash and white ash in well-drained areas. Nearly all ash species have died recently due to infestation by EAB. Most American elms were also dead at WUT, due to past exposure to Dutch elm disease. In contrast, bur oak (*Q. macrocarpa* Michx.) is a

*Representation of common plant species found at different distances from HEAs in field settings [25].*

*These settings included site H with a pipe actively draining oil brine, site I with capped pipe, site J with pipe with no cap and no brine, site K with pipe in roadside ditch, and site L as patch of EPI in field representing a groundwater seep.*

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

**Plants found in field settings at WUT with 100 m** 

Ohio goldenrod (*Oligoneuron ohioense* Frank ex

Smooth blue aster (*Symphyotrichum laeve* L.)

Staghorn sumac (*Rhus typhina* L.)

Orange daylily (*Hemerocallis fulva* L.) X X Poverty oatgrass (*Danthonia spicata* L.) X X X Prairie smoke (*Geum triflorum* Pursh) X X

Shrubby cinquefoil (*Dasiphora fruticosa* L.) X X X

St. John's wort (*Hypericum perforatum* L.) X X

Stinging nettle (*Urtica dioica* L.) X X

Wild bergamot (*Monarda fistulosa* L.) X X

Yellow daylily (*Hemerocallis lilioasphodelus* L.) X X Yellow hawkweed (*Hieracium piloselloides* Vill.) X X X X

Tall buttercup (*Ranunculus acris* L.) X X X

White clover (*Trifolium repens* L.) X X X X X

Timothy (*Phleum pratense* L.) X X X X X X Virginia strawberry (*Fragaria virginiana* Duchesne) X X X X X X X

Wild carrot (*Daucus carota* L.) X X X X

Sweet white clover (*Melilotus officinalis* L.) X

Upland white goldenrod (*Oligoneuron album* Nutt.)

Woolly panic grass (*Dichanthelium acuminatum* Sw.)

White snakeroot (*Ageratina altissima* L.)

**of HEA**

Riddell)


*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*

*These settings included site H with a pipe actively draining oil brine, site I with capped pipe, site J with pipe with no cap and no brine, site K with pipe in roadside ditch, and site L as patch of EPI in field representing a groundwater seep.*

### **Table 4.**

*Plant Communities and Their Environment*

Yellow hawkweed (*Hieracium piloselloides* Vill.)

Yellow sedge (*Carex flava* L.)

**Plants found in white cedar-balsam Fir forest within 100 m** 

*These settings included site E with wood crib and site F with wood crib.*

*white cedar-balsam fir forest along the shoreline of Cape Smith [25].*

**Plants found in field settings at WUT with 100 m** 

Apple (*Malus domestica* L.) X X X X Black raspberry (*Rubus occidentalis* L.) X X Bedstraw (*Galium aparine* L.) X X

Canada anemone (*Anemone canadensis* L.) X

Common buckthorn (*Rhamnus cathartica* L.)

Common mullein (*Verbascum thapsus* L.)

Glossy buckthorn (*Rhamnus frangula* Mill.)

Little green sedge (*Carex viridula* Michx.)

A. Gray ex A. Gray)

Black locust (*Robinia pseudoacacia* L.) X X Calico aster (*Symphyotrichum lateriflorum* L.) X X X

*Representation of common plant species found at different distances from HEAs in forests dominated by eastern* 

Common dandelion (*Taraxacum officinale* Ledeb.) X X X X X X Common ragweed (*Ambrosia artemisiifolia* L.) X X X X X X Common evening primrose (*Oenothera biennis* L.) X X X X

Common raspberry (*Rubus arcticus* L.) X X X X

Eastern poison ivy (*Toxicodendron radicans* L.) X X X X X X

Canada goldenrod (*Solidago canadensis* L.) X X X X X Columbine (*Aquilegia canadensis* L.) X X

Common milkweed (*Asclepias syriaca* L.) X X X

Ebony sedge (*Carex eburnea* Boott) X X X

Heal-all (*Prunella vulgaris* L.) X X

Multiflora rose (*Rosa multiflora* Thunb.) X X X New England aster (*Symphyotrichum novae-angliae* L.) X X X X X

Lesser burdock (*Arctium minus* Bernh.) X X X Little bluestem (*Schizachyrium scoparium* Michx.) X X X X

Common yarrow (*Achillea millefolium* L.) X X Crawe's sedge (*Carex crawei* Dewey) X Daisy fleabane (*Erigeron annuus* L.) X X

Hairy goldenrod (*Solidago hispida* Muhl. ex Willd.) X

Houghton's goldenrod (*Oligoneuron houghtonii* Torr. &

**Plants within 5 m of HEA Plants within 1 m of** 

**E F E F**

**Plants within 5 m** 

**of HEA**

**H I J K L H I J K L**

**HEA**

**Plants within 1 m** 

**of HEA**

**of HEA**

**Table 3.**

**of HEA**

**114**

*Representation of common plant species found at different distances from HEAs in field settings [25].*

with HEAs at WUT were identified. This included forest dominated by balsam poplar reflecting past forest clearing efforts during the hydrocarbon extraction period of the late 1800s. These forest areas now represent Fresh-Moist Poplar Deciduous Forest (FOD8-1) with balsam poplar as the dominant species. Other tree species include conifers such as eastern white cedar, balsam fir, white spruce (*Picea glauca* Moench), black spruce (*P. mariana* Mill.), and red spruce (*P. rubens* Sarg.). Deciduous species include American basswood (*Tilia americana* L.), American elm (*Ulmus Americana* L.), black cherry (*Prunus serotina* Ehrh.), red maple, red oak, staghorn sumac (*Rhus typhina* L.), sugar maple (*A. saccharum* Marshall), tamarack (*Larix laricina* Du Roi), white birch (*Betula papyrifera* Marshall), and white oak (*Q. alba* L.); ash species included black ash predominantly in wetlands along with green ash and white ash in well-drained areas. Nearly all ash species have died recently due to infestation by EAB. Most American elms were also dead at WUT, due to past exposure to Dutch elm disease. In contrast, bur oak (*Q. macrocarpa* Michx.) is a

tree only periodically found in these forests, as it has been previously reported to prefer soil conditions on limestone alvars along areas with recent fire history on Manitoulin Island [25, 29].

Using ELC [37], the shoreline forest areas of Smith's Bay were identified as Fresh-Moist White Cedar-Balsam Fir Coniferous Forest (FOC4-3). That is, the dominant tree species are eastern white cedar and balsam fir along with smaller coverage of species such as balsam poplar, white birch, red maple, and yellow birch; the herbaceous ground cover is depauperate and sparse, likely due to the closed canopy. Oral history revealed these shoreline areas did not burn during the 1865 fire and were dominated at the time by eastern hemlock and yellow birch in poorly drained areas, while eastern white pine (*Pinus strobus* L.) and red pine (*Pinus resinosa* Aiton) dominated the well-drained soils. Due to forestry, eastern hemlock, red pine, and white pine are now essentially absent from the shoreline of Smith's Bay with HEAs. Small areas of remnant eastern hemlock pine forests still occur at WUT but were not targeted for HEAs, as they are in remote areas with very limited access.

The ELC [37] interpretation identified the hay fields as cultural meadow (CUM) due to the long history of regular cutting. Although these fields have been cut on a regular basis for more than 100 years and show very few trees, the plant community includes a diverse array of other herbaceous species likely from seed dispersal, such as prairie smoke (*Geum triflorum* Pursh) along with typical grasses such as timothy (*Phleum pratense* L.).

Each area around the former oil well pipes and wood cribs in forest and field settings show depressions in the soil that vary from 5 to 30 cm in depth. This observed pattern of soil subsidence suggests compaction during HEA installation and past hydrocarbon extraction activities. Recent abandonment activities revealed that these areas demonstrate compacted soil to depths ~ 5 m below grade [21]. Most metal pipes reported in this study have been abandoned and had well depths >110 m, while the wood cribs were variable in construction, and some abandoned with well depths >110 m [21].

At forest site A, a rotted wooden crib (~1.2 × ~1.2 m) was found and inferred to be an HEA with no well in the structure. In this area, the dominant plants (>75% coverage) were ostrich fern (*Matteuccia struthiopteris* L.) along with a few other herbaceous species with the overstory dominated by balsam poplar; other trees in close proximity included balsam fir, red maple, and red osier dogwood. The ostrich fern was replaced by nearly complete cover (>95%) of EPI within 3–4 m of the crib (**Figure 2**). It is noteworthy to identify that specimens of EPI showed mostly bright green leaves and tall plants within 1 m of the crib, while the few specimens of ostrich fern that remained showed leaves with chlorosis (**Figure 3**). In addition, the ostrich ferns closest to the crib were ~¼–½ of the height of the specimens a few meters away from the crib; some EPI adjacent to the crib also showed chlorosis and stunting (**Figure 3**). This reduction of height of ostrich fern was attributed to the HEA. At this site, the balsam poplar was absent within 2–3 m of the crib. The balsam poplar in proximity to the crib demonstrated dead branches on the side facing the crib (**Figure 4**). For this crib, the soil was completely devoid of plants and covered by detritus and leaf matter (**Figure 5**). This pattern of herbaceous and woody plant dieback with robust EPI around HEAs was consistently evident across all forest sites.

Forest site B was in proximity to a metal pipe that contained water with bubbling natural gas. The dominant herbaceous plant in the area was marsh horsetail (*Equisetum palustre*) with the overstory dominated by balsam poplar; other trees were balsam fir, red maple, and red osier dogwood. At site B, the marsh horsetail was essentially absent within about 2–3 m of the pipe with EPI as the dominant (>90%) plant in this area. The balsam poplar was also absent within 2–3 m of the

**117**

**Figure 3.**

*arrow).*

**Figure 2.**

bare and devoid of plants.

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

*Views from August 2, 2016, show site A in the forest dominated by ostrich fern as groundcover that transitions to EPI in close proximity to a rotted wood crib from the 1800s. The view in the figure shows how EPI within 5 m of the wood crib was mostly healthy, except for some small EPI specimen with partial chlorosis represented by yellow leaves (yellow arrow). However, the ostrich fern demonstrates white and green fronds, also indicative of partial chlorosis (white arrow). Also, some ostrich fern shows stunted size and chlorosis (blue arrow).*

pipe, and balsam poplar in proximity to the pipe demonstrated dead branches on the side of the tree facing the pipe, in a similar manner as observed at site A. At 1 m from the pipe, coverage was about 95% EPI. At 30 cm from the pipe, the soil was

*Views from August 2, 2016, show site A in the forest dominated by ostrich fern as groundcover that transitions to EPI in close proximity to a rotted wood crib from the 1800s. The view in Figure 2 shows how EPI within 5 m of the wood crib were mostly healthy, except some small EPI specimen with partial chlorosis represented by yellow leaves. However, the ostrich fern demonstrates white and green fronds also indicative of partial chlorosis (white arrow). Also, some ostrich fern shows stunted size and chlorosis. Figure shows the area within 1.5 m of the crib where the density of all plants declines with total chlorosis evident on ostrich fern (white* 

Forest site C also demonstrated extensive marsh horsetail and ostrich fern in an area that receives water from a pipe that was initially observed to be dry. At this site, a channel extends from the pipe, and EPI is the dominant plant (>90%) along the edge of the channel, for a distance of at least 50 m. That is, the soil of the channel

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*

### **Figure 2.**

*Plant Communities and Their Environment*

Manitoulin Island [25, 29].

(*Phleum pratense* L.).

with well depths >110 m [21].

tree only periodically found in these forests, as it has been previously reported to prefer soil conditions on limestone alvars along areas with recent fire history on

Using ELC [37], the shoreline forest areas of Smith's Bay were identified as Fresh-Moist White Cedar-Balsam Fir Coniferous Forest (FOC4-3). That is, the dominant tree species are eastern white cedar and balsam fir along with smaller coverage of species such as balsam poplar, white birch, red maple, and yellow birch; the herbaceous ground cover is depauperate and sparse, likely due to the closed canopy. Oral history revealed these shoreline areas did not burn during the 1865 fire and were dominated at the time by eastern hemlock and yellow birch in poorly drained areas, while eastern white pine (*Pinus strobus* L.) and red pine (*Pinus resinosa* Aiton) dominated the well-drained soils. Due to forestry, eastern hemlock, red pine, and white pine are now essentially absent from the shoreline of Smith's Bay with HEAs. Small areas of remnant eastern hemlock pine forests still occur at WUT but were not targeted for HEAs, as they are in remote areas with very limited access. The ELC [37] interpretation identified the hay fields as cultural meadow (CUM) due to the long history of regular cutting. Although these fields have been cut on a regular basis for more than 100 years and show very few trees, the plant community includes a diverse array of other herbaceous species likely from seed dispersal, such as prairie smoke (*Geum triflorum* Pursh) along with typical grasses such as timothy

Each area around the former oil well pipes and wood cribs in forest and field settings show depressions in the soil that vary from 5 to 30 cm in depth. This observed pattern of soil subsidence suggests compaction during HEA installation and past hydrocarbon extraction activities. Recent abandonment activities revealed that these areas demonstrate compacted soil to depths ~ 5 m below grade [21]. Most metal pipes reported in this study have been abandoned and had well depths >110 m, while the wood cribs were variable in construction, and some abandoned

At forest site A, a rotted wooden crib (~1.2 × ~1.2 m) was found and inferred to be an HEA with no well in the structure. In this area, the dominant plants (>75% coverage) were ostrich fern (*Matteuccia struthiopteris* L.) along with a few other herbaceous species with the overstory dominated by balsam poplar; other trees in close proximity included balsam fir, red maple, and red osier dogwood. The ostrich fern was replaced by nearly complete cover (>95%) of EPI within 3–4 m of the crib (**Figure 2**). It is noteworthy to identify that specimens of EPI showed mostly bright green leaves and tall plants within 1 m of the crib, while the few specimens of ostrich fern that remained showed leaves with chlorosis (**Figure 3**). In addition, the ostrich ferns closest to the crib were ~¼–½ of the height of the specimens a few meters away from the crib; some EPI adjacent to the crib also showed chlorosis and stunting (**Figure 3**). This reduction of height of ostrich fern was attributed to the HEA. At this site, the balsam poplar was absent within 2–3 m of the crib. The balsam poplar in proximity to the crib demonstrated dead branches on the side facing the crib (**Figure 4**). For this crib, the soil was completely devoid of plants and covered by detritus and leaf matter (**Figure 5**). This pattern of herbaceous and woody plant dieback with robust EPI around HEAs was consistently evident across

Forest site B was in proximity to a metal pipe that contained water with bubbling natural gas. The dominant herbaceous plant in the area was marsh horsetail (*Equisetum palustre*) with the overstory dominated by balsam poplar; other trees were balsam fir, red maple, and red osier dogwood. At site B, the marsh horsetail was essentially absent within about 2–3 m of the pipe with EPI as the dominant (>90%) plant in this area. The balsam poplar was also absent within 2–3 m of the

**116**

all forest sites.

*Views from August 2, 2016, show site A in the forest dominated by ostrich fern as groundcover that transitions to EPI in close proximity to a rotted wood crib from the 1800s. The view in the figure shows how EPI within 5 m of the wood crib was mostly healthy, except for some small EPI specimen with partial chlorosis represented by yellow leaves (yellow arrow). However, the ostrich fern demonstrates white and green fronds, also indicative of partial chlorosis (white arrow). Also, some ostrich fern shows stunted size and chlorosis (blue arrow).*

### **Figure 3.**

*Views from August 2, 2016, show site A in the forest dominated by ostrich fern as groundcover that transitions to EPI in close proximity to a rotted wood crib from the 1800s. The view in Figure 2 shows how EPI within 5 m of the wood crib were mostly healthy, except some small EPI specimen with partial chlorosis represented by yellow leaves. However, the ostrich fern demonstrates white and green fronds also indicative of partial chlorosis (white arrow). Also, some ostrich fern shows stunted size and chlorosis. Figure shows the area within 1.5 m of the crib where the density of all plants declines with total chlorosis evident on ostrich fern (white arrow).*

pipe, and balsam poplar in proximity to the pipe demonstrated dead branches on the side of the tree facing the pipe, in a similar manner as observed at site A. At 1 m from the pipe, coverage was about 95% EPI. At 30 cm from the pipe, the soil was bare and devoid of plants.

Forest site C also demonstrated extensive marsh horsetail and ostrich fern in an area that receives water from a pipe that was initially observed to be dry. At this site, a channel extends from the pipe, and EPI is the dominant plant (>90%) along the edge of the channel, for a distance of at least 50 m. That is, the soil of the channel

### **Figure 4.**

*Views from August 2, 2016, show the groundcover and tree overstory at the rotted wood crib at site A. Figure shows a complete absence of live plants within the former wood crib.*

### **Figure 5.**

*Views from August 2, 2016, show the groundcover and tree overstory at the rotted wood crib at site A. Figure shows dieback of the balsam poplar branches within canopy (yellow arrows) over the former wood crib. Dieback in these overstory branches indicates root death.*

demonstrates bare earth along with patches of EPI and a few specimens of other herbaceous species. The overstory trees in this area are codominant balsam poplar and balsam fir; other trees in the area included red maple, red oak, and eastern white cedar away from the channel. Most balsam poplars along the channel were dead; live balsam poplar was set back from the channel and shows dead branches on the side of the channel. Also the balsam fir close to the channel is short, with a height of <2 m, while balsam fir upslope was up to ~15 m tall.

At forest site C on September 9, 2017, the channel was observed to contain water that appears to have originated from the pipe. This pipe did not generate water until after rain storms from the previous 2 weeks. On this date, red maple saplings growing close to the channel had green leaves and yellow leaves on the same plant. Other red maple found close to the channel was shorter than specimens away from

**119**

**Figure 6.**

**Figure 7.**

*stunted size.*

*(white arrow).*

low areal coverage.

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

*View of site C with iron-stained water that originates from a pipe on September 9, 2017. Figure 6 shows an area that is in close proximity to the pipe, with chlorosis evident in red maple sapling (yellow arrow) and EPI* 

the channel (**Figure 6**). For the EPI in this area, it showed a gradient of responses to exposure to channel, based on distance to the water. Eastern poison ivy specimens that were in direct contact with the water had all three leaves showing red color, while other specimens on the channel above the water line had leaves that were red on the water side and yellow-green leaves upslope of the water. The EPI away from the channel demonstrated less yellow and red color in the leaves with green color evident. In contrast, specimens of EPI found in a short distance upslope had bright green leaves with no discoloration (**Figure 6**). The area closest to the pipe had a few very small plants evident (**Figure 7**). It is inferred the direct contact with water is triggering the rapid onset of chlorosis in leaves. Stunted plant height is attributed to exposure of soil to brine in the past. These phenological responses to brine exposure suggest a mechanism to explain the paucity of plant species, reduced height, and

*View of site C with iron-stained water that originates from a pipe on September 9, 2017. Figure shows an area in very close proximity to the pipe, with very low density of plants with those evident showing severely* 

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*

### **Figure 6.**

*Plant Communities and Their Environment*

**118**

**Figure 4.**

**Figure 5.**

demonstrates bare earth along with patches of EPI and a few specimens of other herbaceous species. The overstory trees in this area are codominant balsam poplar and balsam fir; other trees in the area included red maple, red oak, and eastern white cedar away from the channel. Most balsam poplars along the channel were dead; live balsam poplar was set back from the channel and shows dead branches on the side of the channel. Also the balsam fir close to the channel is short, with a

*Views from August 2, 2016, show the groundcover and tree overstory at the rotted wood crib at site A. Figure shows dieback of the balsam poplar branches within canopy (yellow arrows) over the former wood crib.* 

*Views from August 2, 2016, show the groundcover and tree overstory at the rotted wood crib at site A. Figure* 

*shows a complete absence of live plants within the former wood crib.*

At forest site C on September 9, 2017, the channel was observed to contain water

that appears to have originated from the pipe. This pipe did not generate water until after rain storms from the previous 2 weeks. On this date, red maple saplings growing close to the channel had green leaves and yellow leaves on the same plant. Other red maple found close to the channel was shorter than specimens away from

height of <2 m, while balsam fir upslope was up to ~15 m tall.

*Dieback in these overstory branches indicates root death.*

*View of site C with iron-stained water that originates from a pipe on September 9, 2017. Figure 6 shows an area that is in close proximity to the pipe, with chlorosis evident in red maple sapling (yellow arrow) and EPI (white arrow).*

### **Figure 7.**

*View of site C with iron-stained water that originates from a pipe on September 9, 2017. Figure shows an area in very close proximity to the pipe, with very low density of plants with those evident showing severely stunted size.*

the channel (**Figure 6**). For the EPI in this area, it showed a gradient of responses to exposure to channel, based on distance to the water. Eastern poison ivy specimens that were in direct contact with the water had all three leaves showing red color, while other specimens on the channel above the water line had leaves that were red on the water side and yellow-green leaves upslope of the water. The EPI away from the channel demonstrated less yellow and red color in the leaves with green color evident. In contrast, specimens of EPI found in a short distance upslope had bright green leaves with no discoloration (**Figure 6**). The area closest to the pipe had a few very small plants evident (**Figure 7**). It is inferred the direct contact with water is triggering the rapid onset of chlorosis in leaves. Stunted plant height is attributed to exposure of soil to brine in the past. These phenological responses to brine exposure suggest a mechanism to explain the paucity of plant species, reduced height, and low areal coverage.

Observations at forest site D revealed smooth Solomon's seal as the most common species in close proximity to a pipe that contained no water for a period of 6 months prior to abandonment [21]. A second common plant in the area was nonnative dandelion (*Taraxacum officinale* Ledeb.), likely due to the close proximity to an adjacent abandoned field with extensive dandelion. The overstory trees in this area were codominant balsam poplar and black ash (all dead) with some balsam fir, red maple, red oak, and white spruce. In contrast, the balsam poplar were extensive in the area but absent within 2–3 m of the pipe. The balsam poplar in proximity to the pipe demonstrated dead branches on the side facing the pipe, as observed elsewhere. At 2.0 m from the pipe, coverage was >95% EPI with bare earth and essentially zero plants within 0.5 m of the pipe.

Site E was within the shoreline forest along Smith's Bay, Lake Huron, and contained a wooden crib that measured 1.2 m by 1.2 m and contained water (**Figure 8**). The surrounding forest was dominated by eastern white cedar, while balsam poplar and balsam fir were the most common trees in close proximity to the crib. Following the removal of the wood crib, the area was scanned using electromagnetic induction (EMI: GSSI, Model: Profiler EMP-400). The EMI scanning involves transmission of an electrical field to create a primary magnetic field in the ground. This induced current also then generates a secondary magnetic field in the ground. Both magnetic fields are then quantified as a map of the conductivity of the earth. Soil features such as reinforced concrete impair the performance of the scans, whereas it is well suited for raw soils in the forests. The EMI scans of this site identified no pipes or other metal infrastructure at depth and groundwater close to surface [21]. Abandonment of site F was completed and revealed an oak barrel structure evident below the wood crib that extended to about 9 m depth (**Figure 9**). Below the barrel, an oil well was identified within an eastern white cedar wooden box, and the well was abandoned with cement via pipe to a depth of 130 m ([21]; **Figure 9**).

The herbaceous plant community in proximity to site E was depauperate and sparse within 5 m of the wood crib, likely attributable to the low light levels from the closed forest canopy and heavy leaf litter. Some common lady fern (*Athyrium filix-femina* L.) were evident within 3–5 m of the crib along with EPI. Very few plants were evident in close proximity to the crib, except for some EPI. Balsam poplar growing over the wood crib had dead branches on the side of the crib and live branches on all other sides. The balsam fir that was downslope of the wood crib was short with a maximum height of <2 m, while other balsam fir upslope and adjacent areas had heights of >15 m. No eastern white cedar was evident directly downslope of the wood crib in the drainage path but was upslope.

### **Figure 8.**

*Views of site E with wood crib within the shoreline forest of Smith's Bay. Figure is on November 10, 2015, at the time it was found, after it was burned during 1905.*

**121**

**Figure 10.**

**Figure 9.**

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

Site F was approximately 100 m west of site E within the shoreline forest of Smith's Bay, Lake Huron, and was about 20 m upslope from the shoreline. Site F included a wood crib that measured 1.8 by 1.8 m and contained water (**Figure 10**). After the wood crib was removed, the area was scanned using EMI, similar to site E. This EMI scanning identified no pipes or other metal infrastructure at depth but suggested that groundwater was close to the surface [21]. During abandonment, no metal well pipe was found, but extensive volumes of groundwater were observed within 1 m below grade. The overstory trees in the area were eastern white cedar; however, no mature specimens were evident at the HEA, as it was dominated by

*exists over a natural hydrocarbon seep, about 20 m upslope from Smith's Bay.*

*View of site F near the shoreline of Smith's Bay, Lake Huron, on June 29, 2016. Figure shows how the wood crib* 

*Views of site E with wood crib within the shoreline forest of Smith's Bay. Figure is from November 1, 2016, and shows the excavation in progress with the discovery of a barrel at ~5 m below grade but still 4 m above the well box [21].*

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*

### **Figure 9.**

*Plant Communities and Their Environment*

essentially zero plants within 0.5 m of the pipe.

Observations at forest site D revealed smooth Solomon's seal as the most common species in close proximity to a pipe that contained no water for a period of 6 months prior to abandonment [21]. A second common plant in the area was nonnative dandelion (*Taraxacum officinale* Ledeb.), likely due to the close proximity to an adjacent abandoned field with extensive dandelion. The overstory trees in this area were codominant balsam poplar and black ash (all dead) with some balsam fir, red maple, red oak, and white spruce. In contrast, the balsam poplar were extensive in the area but absent within 2–3 m of the pipe. The balsam poplar in proximity to the pipe demonstrated dead branches on the side facing the pipe, as observed elsewhere. At 2.0 m from the pipe, coverage was >95% EPI with bare earth and

Site E was within the shoreline forest along Smith's Bay, Lake Huron, and contained a wooden crib that measured 1.2 m by 1.2 m and contained water (**Figure 8**). The surrounding forest was dominated by eastern white cedar, while balsam poplar and balsam fir were the most common trees in close proximity to the crib. Following the removal of the wood crib, the area was scanned using electromagnetic induction (EMI: GSSI, Model: Profiler EMP-400). The EMI scanning involves transmission of an electrical field to create a primary magnetic field in the ground. This induced current also then generates a secondary magnetic field in the ground. Both magnetic fields are then quantified as a map of the conductivity of the earth. Soil features such as reinforced concrete impair the performance of the scans, whereas it is well suited for raw soils in the forests. The EMI scans of this site identified no pipes or other metal infrastructure at depth and groundwater close to surface [21]. Abandonment of site F was completed and revealed an oak barrel structure evident below the wood crib that extended to about 9 m depth (**Figure 9**). Below the barrel, an oil well was identified within an eastern white cedar wooden box, and the well

was abandoned with cement via pipe to a depth of 130 m ([21]; **Figure 9**).

of the wood crib in the drainage path but was upslope.

The herbaceous plant community in proximity to site E was depauperate and sparse within 5 m of the wood crib, likely attributable to the low light levels from the closed forest canopy and heavy leaf litter. Some common lady fern (*Athyrium filix-femina* L.) were evident within 3–5 m of the crib along with EPI. Very few plants were evident in close proximity to the crib, except for some EPI. Balsam poplar growing over the wood crib had dead branches on the side of the crib and live branches on all other sides. The balsam fir that was downslope of the wood crib was short with a maximum height of <2 m, while other balsam fir upslope and adjacent areas had heights of >15 m. No eastern white cedar was evident directly downslope

*Views of site E with wood crib within the shoreline forest of Smith's Bay. Figure is on November 10, 2015, at the* 

**120**

**Figure 8.**

*time it was found, after it was burned during 1905.*

*Views of site E with wood crib within the shoreline forest of Smith's Bay. Figure is from November 1, 2016, and shows the excavation in progress with the discovery of a barrel at ~5 m below grade but still 4 m above the well box [21].*

### **Figure 10.**

*View of site F near the shoreline of Smith's Bay, Lake Huron, on June 29, 2016. Figure shows how the wood crib exists over a natural hydrocarbon seep, about 20 m upslope from Smith's Bay.*

Site F was approximately 100 m west of site E within the shoreline forest of Smith's Bay, Lake Huron, and was about 20 m upslope from the shoreline. Site F included a wood crib that measured 1.8 by 1.8 m and contained water (**Figure 10**). After the wood crib was removed, the area was scanned using EMI, similar to site E. This EMI scanning identified no pipes or other metal infrastructure at depth but suggested that groundwater was close to the surface [21]. During abandonment, no metal well pipe was found, but extensive volumes of groundwater were observed within 1 m below grade. The overstory trees in the area were eastern white cedar; however, no mature specimens were evident at the HEA, as it was dominated by

### **Figure 11.**

*View of site F near the shoreline of Smith's Bay, Lake Huron, on June 29, 2016. Figure shows the path where oil-water seepage drains to the shoreline that lacks live vegetation, with white residue along the path.*

balsam poplar and balsam fir directly around the wood crib. Balsam poplar growing over the wood crib has dead branches on the side of the crib and live branches on all other sides. The balsam fir that was downslope of the wood crib was short with a maximum height of <2 m, while other balsam fir upslope and adjacent areas had heights of >15 m. No eastern white cedar was evident directly downslope of the wood crib but was evident upslope with a range of heights (<1 m to 15+ m). The area directly downslope of the wood crib lacked live vegetation within an area about 1 m wide (**Figure 11**).

The herbaceous plant community in proximity to site F was depauperate and sparse within 5 m of the wood crib, similar to site E (**Figure 10**). This pattern of low density and diversity of herbaceous species was also likely partially attributable to the low light levels due to the nearly closed forest canopy and heavy leaf litter. Some mapleleaf viburnum (*Viburnum acerifolium* L.) and common lady fern were also evident within 3–5 m of the crib along with abundant EPI. Very few plants were evident in close proximity to the crib, except a few EPI. There was also a channel that drained water from the crib to Smith's Bay that was 1.0 m wide (**Figure 11**). This drainage channel lacked herbaceous species, while EPI was one of the only species periodically evident along the edge. Also balsam fir trees were evident along the channel and were all short (<2 m); no eastern white cedar were evident along the channel. Specimens of balsam fir away from this channel were all tall (10–15 m). Also rocks downslope from the seep show white particulate residue in the path to the water (**Figure 12**). Also, rocks in Smith's Bay also showed this white particulate and lacked submerged aquatic vegetation (SAV; **Figure 13**). It is prudent to note that SAV was absent only along this area of the shoreline (Figure 13).

Abandonment activity at site G initially involved the excavation of the soils around the wood crib. Soils on the upslope side of the excavated pit appeared to be fine textured with little visual or olfactory evidence of hydrocarbons, while the soils on the downslope were coarse and contained free petroleum product mixed with water. A short time after the excavator removed the surficial soil, groundwater with brown hydrocarbons filled the excavation to approximately 2.0 m below grade. A vacuum truck was used to ensure this oil-water slurry did not drain to the shoreline. Follow-up excavations and dewatering determined clay was extensive at depth below the excavation with no pipe or infrastructure evident. The initial

**123**

**Figure 12.**

**Figure 13.**

*from the wooden crib.*

found in the area upslope [21].

*zero SAV in this area, while adjacent areas had SAV [21].*

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

*Views of site F. Figure shows the seepage path from site F to the lake on April 29, 2016, with white foam arising* 

determination was this site represented a natural hydrocarbon seep. A soil test pit survey was conducted to map the hydrocarbon distribution below grade, and chemical analyses tracked the plume 75 m upslope from the shoreline, where the survey ended. The results from this tracking exercise led to the final determination that this was a natural seep, not a lost HEA, as no evidence of infrastructure was

*Views of site F. Figure from October 12, 2016, shows the shoreline of Smith's Bay, Lake Huron, with a gap in the vegetation (black arrow) and a person with orange vest standing in front of the wood crib in the background. Inspections of the rocks in the water demonstrated the presence of white particulate residue from the seep and* 

Field site H included a pipe that was actively draining an oil-water slurry downslope through a hay field to a wetland-forest complex (**Figure 14**). Since the farmer was not cutting the vegetation around the pipe, black locust (*Robinia* 

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*

### **Figure 12.**

*Plant Communities and Their Environment*

1 m wide (**Figure 11**).

**Figure 11.**

balsam poplar and balsam fir directly around the wood crib. Balsam poplar growing over the wood crib has dead branches on the side of the crib and live branches on all other sides. The balsam fir that was downslope of the wood crib was short with a maximum height of <2 m, while other balsam fir upslope and adjacent areas had heights of >15 m. No eastern white cedar was evident directly downslope of the wood crib but was evident upslope with a range of heights (<1 m to 15+ m). The area directly downslope of the wood crib lacked live vegetation within an area about

*View of site F near the shoreline of Smith's Bay, Lake Huron, on June 29, 2016. Figure shows the path where oil-water seepage drains to the shoreline that lacks live vegetation, with white residue along the path.*

The herbaceous plant community in proximity to site F was depauperate and sparse within 5 m of the wood crib, similar to site E (**Figure 10**). This pattern of low density and diversity of herbaceous species was also likely partially attributable to the low light levels due to the nearly closed forest canopy and heavy leaf litter. Some mapleleaf viburnum (*Viburnum acerifolium* L.) and common lady fern were also evident within 3–5 m of the crib along with abundant EPI. Very few plants were evident in close proximity to the crib, except a few EPI. There was also a channel that drained water from the crib to Smith's Bay that was 1.0 m wide (**Figure 11**). This drainage channel lacked herbaceous species, while EPI was one of the only species periodically evident along the edge. Also balsam fir trees were evident along the channel and were all short (<2 m); no eastern white cedar were evident along the channel. Specimens of balsam fir away from this channel were all tall (10–15 m). Also rocks downslope from the seep show white particulate residue in the path to the water (**Figure 12**). Also, rocks in Smith's Bay also showed this white particulate and lacked submerged aquatic vegetation (SAV; **Figure 13**). It is prudent to note that

SAV was absent only along this area of the shoreline (Figure 13).

Abandonment activity at site G initially involved the excavation of the soils around the wood crib. Soils on the upslope side of the excavated pit appeared to be fine textured with little visual or olfactory evidence of hydrocarbons, while the soils on the downslope were coarse and contained free petroleum product mixed with water. A short time after the excavator removed the surficial soil, groundwater with brown hydrocarbons filled the excavation to approximately 2.0 m below grade. A vacuum truck was used to ensure this oil-water slurry did not drain to the shoreline. Follow-up excavations and dewatering determined clay was extensive at depth below the excavation with no pipe or infrastructure evident. The initial

**122**

*Views of site F. Figure shows the seepage path from site F to the lake on April 29, 2016, with white foam arising from the wooden crib.*

### **Figure 13.**

*Views of site F. Figure from October 12, 2016, shows the shoreline of Smith's Bay, Lake Huron, with a gap in the vegetation (black arrow) and a person with orange vest standing in front of the wood crib in the background. Inspections of the rocks in the water demonstrated the presence of white particulate residue from the seep and zero SAV in this area, while adjacent areas had SAV [21].*

determination was this site represented a natural hydrocarbon seep. A soil test pit survey was conducted to map the hydrocarbon distribution below grade, and chemical analyses tracked the plume 75 m upslope from the shoreline, where the survey ended. The results from this tracking exercise led to the final determination that this was a natural seep, not a lost HEA, as no evidence of infrastructure was found in the area upslope [21].

Field site H included a pipe that was actively draining an oil-water slurry downslope through a hay field to a wetland-forest complex (**Figure 14**). Since the farmer was not cutting the vegetation around the pipe, black locust (*Robinia* 

### **Figure 14.**

*View of site H within a hay field on August 8, 2014. Figure shows the oil-water slurry runoff from a pipe. The vegetation near the pipe demonstrated evidence of leaf chlorosis and stunted size, including red osier dogwood that was upslope and had branches over the pipe (blue arrow), black locust (black arrow), EPI (yellow arrow), and multiflora rose (red arrow).*

*pseudoacacia* L.) and red osier dogwood were evident in the area, along with a few small green ash that had not yet been attacked by the EAB. The herbaceous community upslope of the pipe was typical of the field, with dominance by timothy grass. In contrast, the herbaceous community within 1 m of the pipe was dominated (>75%) by EPI. The EPI specimens located about 1 m from the pipe showed bright green leaves, while specimens in contact with the oil-water slurry showed yellow leaves. The soil within 30 cm of the pipe lacked plants; no plants were evident within the path immediately downslope used by the oil-water slurry. Branches of red osier dogwood in close proximity to the pipe included discoloration of the leaves, suggestive of chlorosis. Black locust leaves also included discoloration. The EPI found in association with the oil-water slurry also demonstrated small size and discoloration of the leaves compared with specimens 1 m away from the oil-water slurry. A few specimens of Virginia strawberry (*Fragaria virginiana* Duchesne) and multiflora rose (*Rosa multiflora* Thunb.) were also evident on the edge of the oil-water slurry and demonstrate discoloration of leaves as well as stunted size. The EPI dominates the vegetation along the path followed by the oil-water slurry downslope, whereas the oil-water slurry is not evident on surface at 15 m from the pipe. Even though the oil-water slurry is not evident at the surface, the EPI follows a path to the edge of the wetland forest, approximately 40 m downslope, and was rare on the edges of the path. When the trees in the wetland forest were inspected, it revealed that those trees in the path of the oil-water slurry were shorter and show a high frequency of dead branches compared with the areas on either side despite no other differences in land use or drainage (**Figure 15**). Inspection of the hay field downslope of the pipe identified EPI was the dominant plant (>50% areal coverage) right through the field to the edge of the woodland. Such disparities in height and survival of varied plants downslope of the pipe imply the oil-water slurry is the causative factor responsible for the local plant responses to exposure to the slurry.

Field site I included a pipe that was capped because it was observed to release large quantities of natural gas in the past by the landowner. The herbaceous plant community within 5 m of the pipe was diverse and essentially identical to the adjacent hay field, including Canada goldenrod, common evening primrose

**125**

**Figure 15.**

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

(*Oenothera biennis* L.), tall buttercup (*Ranunculus acris* L.), and yellow hawkweed

*View of site H within a hay field on August 8, 2014. Figure shows the forest-wetland downslope of the pipe. The trees in the area were shorter (stunted) and also showed dead stems relative to adjacent areas, and EPI was* 

Field site J was essentially identical to site I except the pipe lacked a cap. This pipe was observed to contain no water during the 6 months prior to abandonment. The herbaceous plant community within 5 m of the pipe was somewhat similar to the adjacent hay field. However, within 2–3 m of the pipe, EPI was dominant (>90%). At 30 cm from the pipe, the soil was essentially devoid of plants. Field site K was within a roadside ditch, and the pipe was within 10 m of a residential driveway. This pipe contained no water, but the resident stated it would release water after spring snow melt. This ditch had an array of species evident within 5 m of the pipe, including staghorn sumac; American elm along with specimens of common raspberry (*Rubus idaeus* L.), riverbank grape, Virginia strawberry, and multiflora rose. The plant community was diverse within 1 m of the pipe. At 0.5 m from the pipe, EPI was dominant (>90%). There was bare earth below the

Field site L was within a hay field. The site is defined by an abrupt ecotone between the field plant community with transition to dominance by EPI (>95%) with a few Virginia strawberry. This patch of EPI measured approximately 3 × 3 m. This patch demonstrated healthy EPI with no bare earth. Detailed inspections were completed within this patch. Initially, the area was inspected using a handheld metal detector, to assess possible presence of a metal pipe below grade. This inspection led to no observations, suggesting no presence of metal. Then the area was scanned using EMI, similar to the studies at sites E and F. The EMI scans of this site identified no pipes or other infrastructure at depth but suggested groundwater was close to surface [21]. After the EMI scans were completed, the patch of EPI was excavated, to further inspect the area for oil-stained soil to a depth of 1 m, to complete the search for a lost HEA, with none found [21]. After, the excavation filled with water, and the EPI patch was attributed to a groundwater seep.

(*Hieracium piloselloides* Vill.). However, within 1 m of the pipe, EPI was dominant (>90%). At 30 cm from the pipe, the soil was bare. This pattern of reduced plant diversity and elevated EPI implies that groundwater likely rises

periodically around the base of the capped pipe.

*evident downslope but absent from adjacent field areas.*

EPI vines growing near the pipe.

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic… DOI: http://dx.doi.org/10.5772/intechopen.88150*

### **Figure 15.**

*Plant Communities and Their Environment*

*pseudoacacia* L.) and red osier dogwood were evident in the area, along with a few small green ash that had not yet been attacked by the EAB. The herbaceous community upslope of the pipe was typical of the field, with dominance by timothy grass. In contrast, the herbaceous community within 1 m of the pipe was dominated (>75%) by EPI. The EPI specimens located about 1 m from the pipe showed bright green leaves, while specimens in contact with the oil-water slurry showed yellow leaves. The soil within 30 cm of the pipe lacked plants; no plants were evident within the path immediately downslope used by the oil-water slurry. Branches of red osier dogwood in close proximity to the pipe included discoloration of the leaves, suggestive of chlorosis. Black locust leaves also included discoloration. The EPI found in association with the oil-water slurry also demonstrated small size and discoloration of the leaves compared with specimens 1 m away from the oil-water slurry. A few specimens of Virginia strawberry (*Fragaria virginiana* Duchesne) and multiflora rose (*Rosa multiflora* Thunb.) were also evident on the edge of the oil-water slurry and demonstrate discoloration of leaves as well as stunted size. The EPI dominates the vegetation along the path followed by the oil-water slurry downslope, whereas the oil-water slurry is not evident on surface at 15 m from the pipe. Even though the oil-water slurry is not evident at the surface, the EPI follows a path to the edge of the wetland forest, approximately 40 m downslope, and was rare on the edges of the path. When the trees in the wetland forest were inspected, it revealed that those trees in the path of the oil-water slurry were shorter and show a high frequency of dead branches compared with the areas on either side despite no other differences in land use or drainage (**Figure 15**). Inspection of the hay field downslope of the pipe identified EPI was the dominant plant (>50% areal coverage) right through the field to the edge of the woodland. Such disparities in height and survival of varied plants downslope of the pipe imply the oil-water slurry is the causative factor responsible for the local plant responses to exposure to the slurry. Field site I included a pipe that was capped because it was observed to release

*View of site H within a hay field on August 8, 2014. Figure shows the oil-water slurry runoff from a pipe. The vegetation near the pipe demonstrated evidence of leaf chlorosis and stunted size, including red osier dogwood that was upslope and had branches over the pipe (blue arrow), black locust (black arrow), EPI (yellow* 

large quantities of natural gas in the past by the landowner. The herbaceous plant community within 5 m of the pipe was diverse and essentially identical to the adjacent hay field, including Canada goldenrod, common evening primrose

**124**

**Figure 14.**

*arrow), and multiflora rose (red arrow).*

*View of site H within a hay field on August 8, 2014. Figure shows the forest-wetland downslope of the pipe. The trees in the area were shorter (stunted) and also showed dead stems relative to adjacent areas, and EPI was evident downslope but absent from adjacent field areas.*

(*Oenothera biennis* L.), tall buttercup (*Ranunculus acris* L.), and yellow hawkweed (*Hieracium piloselloides* Vill.). However, within 1 m of the pipe, EPI was dominant (>90%). At 30 cm from the pipe, the soil was bare. This pattern of reduced plant diversity and elevated EPI implies that groundwater likely rises periodically around the base of the capped pipe.

Field site J was essentially identical to site I except the pipe lacked a cap. This pipe was observed to contain no water during the 6 months prior to abandonment. The herbaceous plant community within 5 m of the pipe was somewhat similar to the adjacent hay field. However, within 2–3 m of the pipe, EPI was dominant (>90%). At 30 cm from the pipe, the soil was essentially devoid of plants.

Field site K was within a roadside ditch, and the pipe was within 10 m of a residential driveway. This pipe contained no water, but the resident stated it would release water after spring snow melt. This ditch had an array of species evident within 5 m of the pipe, including staghorn sumac; American elm along with specimens of common raspberry (*Rubus idaeus* L.), riverbank grape, Virginia strawberry, and multiflora rose. The plant community was diverse within 1 m of the pipe. At 0.5 m from the pipe, EPI was dominant (>90%). There was bare earth below the EPI vines growing near the pipe.

Field site L was within a hay field. The site is defined by an abrupt ecotone between the field plant community with transition to dominance by EPI (>95%) with a few Virginia strawberry. This patch of EPI measured approximately 3 × 3 m. This patch demonstrated healthy EPI with no bare earth. Detailed inspections were completed within this patch. Initially, the area was inspected using a handheld metal detector, to assess possible presence of a metal pipe below grade. This inspection led to no observations, suggesting no presence of metal. Then the area was scanned using EMI, similar to the studies at sites E and F. The EMI scans of this site identified no pipes or other infrastructure at depth but suggested groundwater was close to surface [21]. After the EMI scans were completed, the patch of EPI was excavated, to further inspect the area for oil-stained soil to a depth of 1 m, to complete the search for a lost HEA, with none found [21]. After, the excavation filled with water, and the EPI patch was attributed to a groundwater seep.

Information on the herbaceous and woody plant communities along with the distribution of EPI observed within forests and fields at sites A to L at WUT allowed for the resolution of the spatial responses of plants to the presence of HEAs, natural hydrocarbon seep, and groundwater seep (**Table 5**). Species that show growth morphology via rhizome or vine seem to show an ability to occur within 5 m of HEAs, such as EPI, riverbank grape, and Virginia strawberry. Since these patterns were resolved across


**Response of plants and EPI relative to distance from HEA or natural groundwater seep (as approximate** 

*Findings from this study demonstrate the plant communities respond to the HEA and seeps based on water drainage, attributable to brine that contains elevated concentrations of a suite of elements.*

### **Table 5.**

*Summary of response patterns for vegetation found in association with hydrocarbon extraction area, groundwater seep in a field, and hydrocarbon seep in a forest setting, represented as approximate % coverage of EPI in an area.*

**127**

*Eastern Poison Ivy (*Toxicodendron radicans *L.): A Bioindicator of Natural and Anthropogenic…*

forest and field sites, it provides justification for the use of EPI as an indicator species of disturbance. This resolution of general response patterns of plants to this type of disturbance suggests the response patterns could also be used to predict the sites of HEAs, hydrocarbon seeps, or groundwater seeps in areas with oil shale formations.

Wiikwemkoong Unceded Territory history identifies the community-associated

HEAs with disturbed land, and this led to the expulsion of oil men during 1905 [21, 31]. Such identification of disturbance was attributed to the construction of infrastructure like roads as well as clearing of forest in addition to using valuable farmland for HEAs. Community members also described the presence of large barrels used to separate oil from water in fields and forests [21]. The oil men would direct the oil-water slurry through pipes to these barrels. When the decision was made to evict the oil men, the HEAs were burned, and this common disturbance history contributed to the responses of herbaceous and woody plants described in this study. Oral history also identifies that these burned areas were considered scars on Mother Earth that were very slow to recover. However, this recovery of the HEAs was inferred to be slower than expected and resulted in different plants at these sites compared with adjacent areas [21]. Since 109 years passed from the time the HEAs were burned until the initial assessments during 2014, this represents a unique opportunity for learning, to understand how the herbaceous and woody plants responded to this common disturbance history [17]. This understanding arises from un-replicated activity associated with large-scale disturbance of fields and forests at WUT due to the development of HEAs. Such activities represent an opportunity for learning that is consistent to Carpenter's [17] recommendation to consider ecological settings to quantify interactions involving species and document responses of plants and animals to large-scale environmental perturbations. Carpenter [17] recommended that such perturbations, if studied, often provide the chance to document nonrandom change; a reasonable way to interpret such change is with causal inference. In an earlier study [18], a similar idea was expressed about severe perturbations representing a chance to document response of plants and animals but provided the caveat that such events possibly generate unique responses that are difficult to quantify and apply to other settings. Using this documentation of the response of herbaceous and woody plants near HEAs, it pointed to the use of EPI as a bioindicator of the plant community responses to brine as a way to find HEAs. At WUT, it is useful to use EPI as a bioindicator, as it is the only species consistently found within 1 m of HEAs. Other species, such as Virginia strawberry, also show distributions near HEAs, likely attributable to growth morphology via vine. Due to the wide distribution and salinity tolerance of EPI, it is probable this species could be evaluated for use to resolve the response of plants to HEAs beyond WUT. This study reports the observed responses of herbaceous and woody species to episodic exposure to brine in a setting with a common disturbance history. These observations at WUT identified a pattern of reduced diversity of herbaceous and woody species as well as increased coverage of EPI in proximity to drainage from HEAs and natural seeps in fields, and FOD8-1 and FOC4-3 woodlands. These plant communities demonstrate a spatial response to water that originates from HEAs and natural seeps with rapid transition from diverse plant community to dominance by EPI over short distances despite similar exposure to sunlight and a common disturbance history. The identification of this response pattern involving a reduction of plant diversity and dieback of overstory tree branches was directly attributable to brine found near HEAs and seepage in fields and forests, representing an ecotone

*DOI: http://dx.doi.org/10.5772/intechopen.88150*

**6. Discussion**

forest and field sites, it provides justification for the use of EPI as an indicator species of disturbance. This resolution of general response patterns of plants to this type of disturbance suggests the response patterns could also be used to predict the sites of HEAs, hydrocarbon seeps, or groundwater seeps in areas with oil shale formations.
