Effects of Restoration on Carbon Storage in Smelter ......2010/01/06 · part, for scholarly...
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Effects of Restoration on Carbon Storage in Smelter-
impacted Industrial Barrens
by
Robyn Rumney
A thesis submitted in partial fulfillment
of the requirements for the degree of
Master of Science (MSc) in Biology
The Faculty of Graduate Studies
Laurentian University
Sudbury, Ontario, Canada
© Robyn Rumney, 2019
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THESIS DEFENCE COMMITTEE/COMITÉ DE SOUTENANCE DE THÈSE
Laurentian Université/Université Laurentienne
Faculty of Graduate Studies/Faculté des études supérieures
Title of Thesis
Titre de la thèse Effects of Restoration on Carbon Storage in Smelter-impacted Industrial Barrens
Name of Candidate
Nom du candidat Rumney, Robyn
Degree
Diplôme Master of Science
Department/Program Date of Defence
Département/Programme Biology Date de la soutenance December 17, 2019
APPROVED/APPROUVÉ
Thesis Examiners/Examinateurs de thèse:
Dr. John Gunn
(Supervisor/Directeur de thèse)
Dr. Nathan Basiliko
(Co-supervisor/Co-directeur de thèse)
Dr. Peter Beckett
(Committee member/Membre du comité)
Dr. Erik Emilson
(Committee member/Membre du comité)
Approved for the Faculty of Graduate Studies
Approuvé pour la Faculté des études supérieures
Dr. David Lesbarrères
Monsieur David Lesbarrères
Dr. Brian Amiro Dean, Faculty of Graduate Studies
(External Examiner/Examinateur externe) Doyen, Faculté des études supérieures
ACCESSIBILITY CLAUSE AND PERMISSION TO USE
I, Robyn Rumney, hereby grant to Laurentian University and/or its agents the non-exclusive license to archive and
make accessible my thesis, dissertation, or project report in whole or in part in all forms of media, now or for the
duration of my copyright ownership. I retain all other ownership rights to the copyright of the thesis, dissertation or
project report. I also reserve the right to use in future works (such as articles or books) all or part of this thesis,
dissertation, or project report. I further agree that permission for copying of this thesis in any manner, in whole or in
part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or, in their
absence, by the Head of the Department in which my thesis work was done. It is understood that any copying or
publication or use of this thesis or parts thereof for financial gain shall not be allowed without my written
permission. It is also understood that this copy is being made available in this form by the authority of the copyright
owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted
by the copyright laws without written authority from the copyright owner.
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ABSTRACT
Landscape carbon (C) storage is a key component of climate change mitigation. Globally,
industrial barrens cover large areas and their restoration can facilitate C storage in otherwise
under-utilized sites, while concomitantly enhancing numerous other ecosystem services. I
assessed how restoration of smelter impacted barren land enhanced C storage by studying a site
in Sudbury, Ontario near a former Ni and Cu metal smelter that ceased operation in 1972. The
site was treated by aerial liming, fertilizing, and grass and legume seeding in 1994-1997,
followed by jack pine (Pinus banksiana) planting in the upland areas in 1997-2001. Forty-five
0.1 ha size plots were selected across restored and untreated adjoining areas, 32 in exposed
upland industrial barrens and 13 in sheltered lowland valleys. The focus of my study was on
upland industrial barrens, which exhibited severe site conditions and little natural regrowth. I
measured the amount of C in coarse woody debris, fine woody debris, herbs, mineral soil,
organic soil (LFH layers), shrubs, and trees in each plot. Measures of wetness index, plant
species richness, soil metal concentrations, soil pH, distance from smelter, and elevation were
then used to assess factors affecting total ecosystem C storage.
In lowland valleys where no active tree planting occurred (only natural regeneration) the
treatments with lime, fertilizer, and grass and legume seed showed a 38% increase in C storage
(101.1 ± 5.5 Mg C ha-1 (mean ± S.E.)) compared to untreated lowland plots (73.3 ± 5.9 Mg C ha-
1). In upland areas where growing conditions were more severe (i.e., thin soils, low moisture),
tree C increased from 0.5 ± 0.4 Mg C ha-1 in areas of natural regeneration to 19.3 ± 1.4 Mg C ha-1
following liming, fertilizing, seeding, and tree-planting. There was no significant difference in
total C storage in untreated reference plots (36.1 ± 8.4 Mg C ha-1) compared to limed, fertilized,
seeded, and tree-planted plots (58.2 ± 4.4 Mg C ha-1), likely due to variable site conditions across
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the landscape. Wetness index, plant species richness, and soil bioavailable metal concentrations
were the best predictors of C storage in upland industrial barrens, with the best model explaining
64% of variance in C storage. Overall, mineral soil remained the largest C pool in both the
uplands (53%) and the lowlands (40%). The forests in my study were not mature, so C storage is
expected to continue to increase in the future. My findings demonstrate that soil amendments and
tree planting can increase tree C storage in industrial barrens, but site characteristics, particularly
wetness, are key to the rate of total C accumulation. C storage in less disturbed lowland valleys
also benefitted from restoration. Well-designed restoration efforts that optimize C storage in
globally extensive industrial barrens can therefore sequester C and may in turn assist in climate
change mitigation.
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ACKNOWLEDGMENTS
Thank you to my supervisors Dr. John Gunn and Dr. Nathan Basiliko for the opportunity
to work with them on this project and for guidance along the way. Thank you to my committee
members Dr. Peter Beckett and Dr. Erik Emilson for feedback and direction throughout my
research. Thanks to the Ministry of Environment, Conservation and Parks for allowing continued
research at Daisy Lake Uplands Provincial Park. A big thanks to Emily Smenderovac for going
above and beyond during my fieldwork, calculations, and R crises. Thank you to Dr. Trevor
Jones for sharing your expertise of carbon pool calculations and your field equipment. Thank
you to Dr. Brie Edwards for statistics help that added the finishing touches to my linear
regression. Thanks to Brittany Rantala-Sykes for your extraordinary plant identification. This
project would not have been possible without the help of my fearless field crew: Meghan Ward,
Kalpana KC, James Bull, and Aaron Rysdale who went out rain or shine. Thanks to everyone
else at the Cooperative Freshwater Ecology Unit for their advice, support, friendship, and
entertaining lunch conversations. I would also like to extend the warmest thanks to all my family
members and friends for supporting me throughout this process.
Financial support was provided by L-CARE (Landscape Carbon Accumulation through
Reductions in Emissions), the Ecolac program, the Tom Peters Memorial Mine Reclamation
Award, and the Fisheries and Oceans Habitat and Restoration Scholarship.
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TABLE OF CONTENTS
Effects of Restoration on Carbon Storage in Smelter-impacted Industrial Barrens ............................. i
ABSTRACT ................................................................................................................................................ iii
ACKNOWLEDGMENTS .......................................................................................................................... v
LIST OF FIGURES ................................................................................................................................. viii
LIST OF TABLES ..................................................................................................................................... ix
LIST OF ABBREVIATONS ...................................................................................................................... x
1.0 Introduction ......................................................................................................................................... 1
2.0 Methods ................................................................................................................................................ 7
Site description and plot-setup ...................................................................................................................... 7
Coarse woody debris C storage .................................................................................................................... 9
Fine woody debris C storage ...................................................................................................................... 10
Understory: Herb and shrub C storage ...................................................................................................... 11
Tree C storage............................................................................................................................................. 11
Plant species richness ................................................................................................................................. 13
Soil chemistry and C storage ...................................................................................................................... 13
Wetness index .............................................................................................................................................. 15
Distance from smelter ................................................................................................................................. 16
Data analysis .............................................................................................................................................. 16
3.0 Results ................................................................................................................................................ 20
Effect of treatment on C storage ................................................................................................................. 20
C pools: Upland industrial barrens ............................................................................................................ 20
Predictors of C storage: Upland industrial barrens ................................................................................... 21
Mineral soil pH ........................................................................................................................................... 22
4.0 Discussion........................................................................................................................................... 29
C storage: Upland industrial barrens ......................................................................................................... 29
Predictors of C storage ............................................................................................................................... 32
C storage: Lowland valleys ........................................................................................................................ 33
Restoration recommendations .................................................................................................................... 34
Limitations of study ..................................................................................................................................... 35
Conclusion .................................................................................................................................................. 36
Future studies.............................................................................................................................................. 36
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REFERENCES .......................................................................................................................................... 38
APPENDIX ................................................................................................................................................ 44
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LIST OF FIGURES
Figure 2.1 Map of Daisy Lake watershed plots in upland industrial barrens (> 280 m centre
elevation) (n = 32) and lowland valleys (≤ 280 m centre elevation) (n = 13). Shading indicates
tree-planted (T), limed, fertilized, and seeded (L), and limed, fertilized, and seeded + tree-planted
(L+T) treatments. Untreated (U) areas are not shaded. Daisy catchments H, I, and J are labelled.
Arrow indicates direction of historic Coniston smelter.
Figure 2.2 Layout of sampling points at each 0.1 ha plot. FWD-1 through FWD-4 were LIS
locations for FWD survey. Soil depth was measured at 1-16, while soil samples were taken at
even numbers only. Understory sampling occurred in 1 m2 square quadrats located at numbers 4,
8, 12, and 16. All other sampling occurred throughout entire plot.
Figure 2.3 Soil sampling protocols for organic and mineral soil layers. Mineral soil was divided
into 3 depths (0-5 cm, 5-10 cm, 10-20 cm) and sampled with a1.5 cm diameter soil corer and
organic soil was collected using a 5 cm circular frame.
Figure 3.1 Total ecosystem C storage (Mg C ha-1 ± SE) in upland industrial barrens among
untreated (U), limed, fertilized, seeded (L), tree-planted (T), and limed, fertilized, seeded + tree-
planted (L+T) plots (n = 32 plots). Different letter designations above bars indicate significant
differences at p < 0.05.
Figure 3.2 C storage (Mg C ha-1 ± SE) in each C pool (CWD, FWD, herb, mineral soil, organic
soil, shrub, and tree) in upland industrial barrens among untreated (U), limed, fertilized, seeded
(L), tree-planted (T), and limed, fertilized, seeded + tree-planted (L+T) plots (n = 32 plots).
Different letter designations in tree C indicate significant differences at p < 0.05. Only tree C
differed significantly by treatment.
Figure 3.3 Wetness index (z-scores) in upland industrial barrens among untreated (U), limed,
fertilized, seeded (L), tree-planted (T), and limed, fertilized, seeded + tree-planted (L+T) plots (n
= 32 plots). Different letter designations above plots indicate significant differences at p < 0.05.
Figure 3.4 Plant species richness (± SE) in upland industrial barrens among untreated (U),
limed, fertilized, seeded (L), tree-planted (T), and limed, fertilized, seeded + tree-planted (L+T)
plots (n = 32 plots). Different letter designations above bars indicate significant differences at p
< 0.05.
Figure 3.5 Total ecosystem C storage (Mg C ha-1 ± SE) at lowland valley untreated (U) and
limed, fertilized, seeded (L) plots (n = 13). Different letter designations above bars indicate
significant differences at p < 0.01.
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LIST OF TABLES
Table 3.1 Linear regression relating total ecosystem C storage (Mg C ha-1) in upland industrial
barren plots (n = 32 plots) to wetness index, plant species richness, PC1 (first axis of principal
component of soil bioavailable [As], [Cd], [Co], [Cu], [Ni], [Pb]), soil pH, jack pine frequency,
distance from smelter, and elevation (MASL). Model was generated using backward selection
with second order Akaike Information Criterion (AICc).
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LIST OF ABBREVIATONS
COC- chemical(s) of concern
CWD- coarse woody debris
DCRF- decay-class reduction factor
DOC- dissolved organic carbon
FWD- fine woody debris
ICP-MS- inductively coupled plasma mass spectrometry
L- limed, fertilized, seeded plots
L+T- tree-planted + limed, fertilized, seeded plots
LIS- line intersect sampling
PC- principal component
QAQC- quality assurance and quality control
SOC- soil organic carbon
SOM- soil organic matter
SRF- structural reduction factor
T- tree-planted plots
U- untreated plots
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1.0 Introduction
Climate change is a challenge faced by society that requires multi-faceted solutions. One
natural climate solution is to decrease atmospheric CO2 concentrations by storing more carbon
(C) in forest ecosystems (Griscom et al., 2017). Boreal forests alone store approximately 550 Gt
C, which is 30% of Earth’s total terrestrial C pool (Bradshaw et al., 2009). Therefore, forest C
dynamics are a key component of global C budgets (Kurz et al., 2013).
Forest net C balance is determined by C uptake during net primary production and C loss
during autotrophic respiration, decomposition (heterotrophic respiration), and oxidation in forest
fires (Kurz et al., 2013). When forests have net C uptake they are a C sink (Kurz et al., 2013) and
store C in coarse woody debris (CWD), fine woody debris (FWD), herbs, mineral soil, organic
soil (LFH layers), shrubs, and trees (Lambert et al., 2005). Boreal forests store around 60% of C
in soil, 20% in biomass (Pan et al., 2011), and 20% in downed woody debris (CWD and FWD)
(Russell et al., 2015).
Boreal forests have been estimated to sequester approximately 2.1 Mg C ha-1 y-1 (Amiro
et al., 2010). Boreal forest deciduous trees are larger C sinks than boreal conifers, with pure
black spruce (Picea mariana) and jack pine (Pinus banksiana) stands inputting 1.3 Mg C ha-1 y-1
(Gower et al., 2001). Boreal forest C storage is highly variable and dependent on tree age,
species composition, density, site characteristics, and disturbance. Gao et al. (2017) found boreal
forest C storage to be reflective of stand age, increasing from 96.5 ± 5.1 Mg C ha-1 in 8-year-old
stands to 327.9 ± 11.9 Mg C ha-1 in 147-year-old stands, and then decreasing to 271.1 ± 13.6 Mg
C ha-1 in 210-year-old stands. Hazlett et al. (2005) found highly variable C storage that differed
by forest position, with 95-year-old upland stands storing 28.3 to 135.08 Mg C ha-1 and 95-year-
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old lowland riparian stands storing 29.3 to 269.1 Mg C ha-1, possibly because of disparity in
species compositions. Boreal forests experience C loss after stand-replacing disturbances, but
become C sinks again within 20 years of revegetation (Amiro et al., 2010). Young forests that
have grown back after a disturbance are net C sinks, while recently disturbed forests (i.e., fire,
insects, etc.) that have not recovered are net C sources (DeLuca & Boisvenue, 2012). Climate
change is expected to exacerbate boreal forest fire disturbance by increasing the annual number
of fires and area burned (Flannigan et al., 2006), which could turn larger areas into temporary C
sources (Amiro et al., 2010). More severe and frequent forest fires could also burn deep, legacy
soil C that escaped past fires (Walker et al., 2019). Minor insect pest disturbances can benefit C
storage, as they promote tree diversity and growth and therefore increase C influx (Gao et al.,
2017). Major stand-replacing insect disturbances, however, release C, and with climate change
these events could become more prolific (Kurz et al., 2013). Anthropogenic CO2 fertilization and
N deposition could also increase forest productivity, with uncertain net effects on C storage
(DeLuca & Boisvenue, 2012).
Large areas of the world have been severely damaged by mining and smelting (Kozlov &
Zvereva, 2007; Moore & Luoma, 1990) creating extensive industrial barrens where C storage is
currently minimal (Kozlov & Zvereva, 2015; Sherman and Beckett, 2003) because of vegetation
and soil loss (Kozlov & Zvereva, 2007). Forest regrowth after disturbance creates a C sink that,
while not enough to solely reverse climate change, is expected to positively affect the global
climate system (Pugh et al., 2019). Increasing Earth’s total forested area, such as by reforesting
industrial barrens and other large areas of disturbance, may then help limit climate warming from
exceeding the 1.5°C above pre-industrial levels that is one of the stated goals of the most recent
ICPP reports (Lewis et al., 2019). The extensive industrial barrens (> 80,000 ha) that surrounded
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the smelters in Sudbury, Canada, are among the best studied examples of large-scale industrial
barren disturbance and restoration, and its barrens that have been subjected to decades of
restoration represent a potentially large C sink for this study (City of Greater Sudbury, 2018;
Kozlov & Zvereva, 2007; Sherman & Beckett, 2003).
Sudbury lies on the ecotone of the Great Lakes – St. Lawrence forest region and the
boreal forest (Amiro & Courtin, 1981), therefore Sudbury contains elements of both forest types
and can be described as a mixed boreal forest (Hutchinson & Whitby, 1977). In the 1970s,
reductions in Sudbury’s atmospheric pollution began with closure of the Coniston smelter and an
ore-sintering plant near Copper Cliff, approximately 50% initial decrease in overall SO2 and
metal emissions, and the erection of a 381 m “super stack” (then the tallest in the world) with an
electrostatic precipitator (Freedman & Hutchinson, 1980). These measures greatly reduced local
pollution, especially ground level fumigation events that were devastating to vegetation (Gunn et
al., 1995). Emission reductions facilitated some natural re-growth of mainly white birch (Betula
papyrifera) but soil pH remained low (2.0- 4.5), so dolomitic limestone (Ca and Mg) was used as
a soil amendment when a large-scale land reclamation program began in 1978 (Beckett &
Negusanti, 1990). A fertilizer and seed mixture was also applied as part of the re-greening
strategy (Winterhalder, 1983). Between 1978 and 2018 the program limed 3,478 ha, fertilized
3,252 ha, seeded 3,179 ha, and planted 10,214,559 trees and shrubs (City of Greater Sudbury,
2018). Sudbury’s restoration was focused mainly on rocky barren uplands with little natural
regeneration. Emission reductions have also continued and current emissions of sulphur and
metal particulates are now approaching 1% of historic highs in the 1960s (Carmichael, 2018).
Sudbury’s regreening program was initially focused on creating an ecosystem, reducing
soil erosion, providing vegetation cover for aesthetic reasons (i.e., improving the image of the
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city, providing recreation areas, etc.), and for economic improvement of the city (Beckett &
Negusanti, 1990; City of Greater Sudbury, 2018; Szkokan-Emilson et al., 2011). As the program
evolved it took on more ecological challenges, such as increasing terrestrial biodiversity and
improving water quality in local lakes (City of Greater Sudbury, 2018; Dixit et al., 1996). To
date, however, apart from the work by Sherman and Beckett (2003), relatively little attention has
been paid to the role of restoration treatments in sequestering of atmospheric C.
The Sherman and Beckett (2003) study did show considerable C sequestration shortly
after liming and tree planting, but the work included sand plains and other relatively
homogeneous measurement plots and did not address the extreme variability that could occur
across the topography of the damage zone. Exposed hills, for example, appeared the most
damaged and most difficult to restore, while low-lying valleys were more protected and
maintained more of the original natural vegetation and deeper soils (Kozlov & Zvereva, 2007;
Winterhalder, 1995). Valleys also continued to collect soil as the hilltops eroded, adding to
lowland soil depth (Winterhalder, 1995). Therefore, it was clear going into this study that
microscale and catena-level topography would likely be important controls on C storage in
Sudbury’s industrial barrens.
Other site characteristics were also expected to affect revegetation and C storage in
Sudbury’s barrens. Distance from historic smelters affected the disturbance intensity of
atmospheric pollution, as Ni, Cu, and SO4 pollution increased with proximity to the smelters
(Freedman & Hutchinson, 1980). In Sudbury, limited moisture in barren uplands also clearly
impeded natural recolonization and ecosystem C sequestration following emission reductions
(McCall et al., 1995; Mensah et al., 2016). Plant species richness and diversity may also affect C
storage in Sudbury’s restored barrens by increasing vegetative niche portioning, facilitating soil
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nutrients, and increasing the chances of having more productive and higher biomass yielding
species (Lewis et al., 2019; Mensah et al., 2016). Finally, soil metal concentrations were
expected to impact C storage by affecting plant growth and soil microbial processes (Bolan et al.,
2003). An extensive study of soil metals on their potential toxicity to plants identified seven
metals (As, Cd, Co, Cu, Ni, Pb, Se) that were considered the principal chemicals of concern
(COC) in the Sudbury area (SARA Group, 2009).
I went into this study with the prediction that tree-planting Sudbury’s industrial barrens
could create large C sinks, a practice that if carried out across global brownfield environments,
could contribute to climate change mitigation. Lewis et al. (2019) found reforestation to be the
largest natural pathway to hold global climate warming at below 1.5˚C. Reforestation also
benefits biodiversity, habitat, air quality, water quality, flood control, and soil quality (Griscom
et al., 2017). Tree-planting has net positive effects on long-term tree and downed woody debris C
storage (Griscom et al., 2017; Keith et al., 2009). Although tree-planting increases aboveground
C, many temperate and boreal terrestrial ecosystems store most of their C in soils, and the
relationship between tree-planting and soil C storage is less clear (DeLuca & Boisvenue, 2012;
Nave et al., 2013). Soil C is generally the largest temperate and boreal C pool because it is
relatively stable across time and disturbance regimes (DeLuca & Boisvenue, 2012). However,
Nave et al. (2013) found that tree-planting on industrial barrens causes an initial decline in
mineral soil C followed by a significant increase 15 years post-planting. Long-term organic soil
C also increases after tree-planting due to the addition of litter and woody debris (Nave et al.,
2013). Keith et al. (2009) agreed that forests continue to sequester C in soils even after forests
reach maturity. Tree species also affects soil C storage, with coniferous trees having shallow
roots that accumulate more soil C in the organic than mineral soil horizons (Jandl et al., 2007).
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Generally, however, boreal forests tend to store more total soil C under coniferous than
deciduous trees (Vesterdal et al. 2013). Therefore, it is of note that conifers comprised 95% of
the trees planted in Sudbury’s regreening program between 1979 and 2018 (City of Greater
Sudbury, 2018).
To date, nearly 40 years after the large-scale land reclamation began in Sudbury, there is
little knowledge of how Sudbury’s soil amendment procedures and tree-planting have affected
ecosystem C storage. We know that treating acidic and nutrient-limited forests with dolomitic
limestone generally increases plant C storage by neutralizing pH, reducing the bioavailability of
metals, and providing nutrients (Bolan et al., 2003; Moore & Ouimet, 2006). Dolomitic liming
fertilizes the soil with Ca and Mg, which are limiting nutrients in northern hardwood trees
(Moore & Ouimet, 2006). Furthermore, lime mitigates the phytotoxic impacts of acidity-
dependent trace metals, including Al, which negatively impact plant growth and development
(Bengtsson et al., 1988). High soil concentrations of bioavailable metals can also decrease the
uptake of plant essential nutrients by competing for binding sites (Bengtsson et al., 1988). Al, for
example, can cause P, a plant essential nutrient, to adsorb and become biologically unavailable
(Giesler et al., 2004). Therefore, liming effectively promotes plant growth and C storage. Liming
also increases microbial decomposition, which could decrease soil C (Haynes & Naidu, 1998).
However, liming’s positive effect on plant growth also supplements litter inputs, increasing soil
C (Paradelo et al., 2015). Liming-induced microbial activity could also deposit extracellular
binding agents that increase soil aggregation, which reduces soil erosion and increases soil depth
(Haynes & Naidu, 1998). Jandl et al. (2007) found that liming and fertilizing decreased soil C
due to losses from microbial decomposition and dissolved organic C (DOC) leaching. In
Sudbury, liming, fertilizing, and seeding facilitated the recolonization of plant species
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(Winterhalder, 1996). Establishing plant cover generally reduces soil erosion and seeding with
N-fixing legume species improves soil N availability, both of which should promote continued
plant growth (Winterhalder, 1996). Seeding the understory, however, could also create
competition with trees for light and nutrients (Winterhalder, 1996).
The objectives of my study were: i) to compare the C storage of smelter-impacted upland
industrial barrens and naturally revegetated lowlands across untreated plots (U), limed, fertilized,
and grass and legume seeded plots (L), tree-planted plots (T), and limed, fertilized, grass and
legume seeded + tree-planted plots (L+T), and ii) to determine how landscape characteristics
(wetness index, plant species richness, soil metal concentrations, soil pH, jack pine frequency,
distance from smelter, elevation) affect C storage following these treatments on upland industrial
barrens.
I hypothesized that: i) liming, fertilizing, and grass and legume seeding would increase C
storage both above and below ground in Sudbury’s upland industrial barrens and lowland
valleys; ii) planting conifer trees in Sudbury’s upland industrial barrens would increase C storage
over time, and iii) site characteristics (i.e., topography, wetness index, plant species richness, soil
metal concentrations, etc.) would affect C storage across all restoration treatments in upland
industrial barrens.
2.0 Methods
Site description and plot-setup
My study was conducted in small adjacent headwater catchments of the Daisy Lake
watershed in Sudbury, ON. Daisy Lake is a 36 ha lake located 3.5 km southwest of the
abandoned Coniston Ni and Cu smelter that operated until 1972 (Szkokan-Emilson et al., 2011).
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The Daisy Lake watershed was severely contaminated and partially denuded of vegetation and
soil by atmospherically deposited metals in a disturbance gradient away from the Coniston
smelter (with no vegetation closest to the smelter and minimal impact further away); it primarily
consisted of industrial barrens on uplands and steep slopes and naturally regenerated forests in
lowland valleys (Dixit et al., 1996). White birch naturally regenerated in some of the Daisy Lake
watershed (Dixit et al., 1996). Additionally, the Daisy Lake watershed’s valleys contained
vegetative and soil refugia, with tree core data from the 1990s aging the oldest trees in the
watershed to 1908 (Szkokan-Emilson et al., 2011; Vanttinen, 1993).
The study was conducted in and around three adjoining catchment areas labelled J, I, and
H with increasing distance from the abandoned smelter site located approximately 3-5 km
northeast of the Daisy catchments (Fig. 2.1). Daisy J, the closest catchment to the smelter, is a 39
ha catchment of mostly rock barrens that was aerially limed with 410 tons of coarse dolomitic
limestone (53.9% CaCO3, 44.8% MgCO3) in 1994, and in 1997 fertilized (N-P-K of 6-24-24)
and seeded with five species of grasses and two species of legumes (City of Greater Sudbury,
2019; Gunn et al., 2001; Szkokan-Emilson et al., 2011). The next catchment, Daisy I is a 32 ha
mostly barren catchment that was predominately untreated (Gunn et al., 2001). Daisy H is a 29
ha catchment consisting of low-lying valleys with eroded soil inputs and both residual and
naturally regenerating vegetation; it was entirely untreated.
Three years (1997) and then again 7 years (2001) after the initial aerial liming, jack pine
seedlings were planted by municipal tree planting crews in much of Daisy J, a small section of
Daisy I, and just peripheral to the Daisy watershed (City of Greater Sudbury, 2019). Tree
planting only occurred in the upland areas, and crews were somewhat haphazard in tree
placement, varying tree densities based on local site conditions (i.e., apparent soil depth).
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I established forty-five circular plots of 0.1 ha size in 2018, twenty-four years after the
initial aerial liming treatment, across Daisy J, Daisy I, Daisy H, and just peripheral to the
watershed in areas of limed, fertilized, and grass and legume seeded sites (L), tree-planted sites
(T), limed, fertilized, and grass and legume seeded + tree-planted sites (L+T), and untreated (U)
sites (Fig. 2.1). I chose plots based on historic sampling points when possible, and additional
plots were added to increase replication across treatments. Tree-planted plots were characterized
as those containing > 20 jack pine. It was impossible to distinguish between planted and second-
generation jack pine, as tree size was variable depending on site and shading. Final data were
collected from 45 plots, with 15 U plots, 10 L plots, 8 T plots, and 12 L+T plots. Plot coordinates
and elevation were measured using GNSS (ISXBlue GPS with terra4go collector app) placed on
a 2 m levelled pole, with measurements taken after sub-meter accuracy was attained. Thirty-two
of the established plots were classified as upland industrial barrens (> 280 m centre elevation),
with 5 U plots, 7 L plots, 8 T plots, and 12 L+T plots (Fig. 2.1). Upland industrial barren plots
were the focus of my study. A remaining 13 plots were described as lowland valleys (≤ 280 m
centre elevation), of which 10 were U and 3 were L plots (Fig. 2.1). Valley plots were not barren
prior to restoration, so C storage was compared but I did not pursue further analysis.
Coarse woody debris C storage
Coarse woody debris (CWD) was defined as any downed wood that was not self-
supporting with a midpoint located within the plot boundary and a midpoint diameter ≥ 10 cm.
All CWD was surveyed within each plot and the species (if identified), length, decay class at
midpoint, and dimensions at the top, middle, and bottom were recorded. A 5 level decay class
system was used to differentiate decomposition and derive densities (Harmon et al., 2011). I
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calculated the volume (V) of each piece of CWD using the conic-paraboloid equation from
Fraver et al. (2007):
(1) V = L/12 (5Ab + 5Au + 2√𝐴𝑏𝐴𝑢)
where L is length of CWD, Ab is the area of base end of CWD, and Au is the area of the upper
end of CWD. I then calculated CWD C by multiplying volume (V) by density (S) (Harmon et al.,
2011) and a C ratio of 0.50 (Laiho & Prescott, 2011; Luyssaert et al., 2008; Smith et al., 2003):
(2) CWD C (g) = V * S * 0.50
The biomass to C ratio did not vary with decay stages (Lambert et al., 1980). Total CWD C for
each plot was calculated by summing the CWD C, converting to Mg, and dividing by plot area:
(3) CWD C (Mg C ha-1) = Σ(CWD C (g)) / 1x106 / 0.1 ha
Fine woody debris C storage
Fine woody debris (FWD) was defined as downed, non-self-supporting wood with a
diameter at line intersect sampling (LIS) between 1.0 cm and 9.9 cm. FWD was surveyed using
LIS along four 17.84 m transects that ran north-south and east-west through the centre point of
each plot (Fig. 2.2). FWD for each transect was tallied by diameter at transect and decay class. I
calculated FWD biomass (W) per transect area with an equation from Van Wagner (1968),
which used an average of decay class densities for downed wood in Harmon et al. (2011):
(4) W = 𝜋2 * S * Σd2/ 8L
where S is the mean density along each LIS, d is diameter of FWD, and L is LIS length.
Total FWD C (Mg C ha-1) for each plot was then calculated by scaling the biomass to per
hectare, multiplying it by 0.50, and finding the mean FWD C of the four LIS transects (Laiho &
Prescott, 2011; Luyssaert et al., 2008; Smith et al., 2003).
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Understory: Herb and shrub C storage
I sampled understory C by establishing four 1 m2 quadrats per plot, located at the far edge
of each transect (Fig. 2.2). Herbs were defined as dead and living biomass ≤ 1 m high, including
vegetation leaning in but not rooted in the quadrat. The percent cover of each quadrat was
categorized into rock, organic soil, mineral soil, lichen, fungi, and plants (identified to species
when possible). The herb layer within each quadrat was harvested at the ground and bagged. The
shrub layer was defined as any biomass > 1 m high and ˂ 3 cm diameter at breast height (DBH).
Shrubs rooted in quadrats were harvested at the base (including any branches extending out of
quadrat) and bagged. Herbs and a subset of shrub samples (n = 53) were dried at 70˚C for 48
hours and then weighed. Many shrubs were too large to process in drying ovens and others were
disturbed by small mammals while in storage. The subset of shrubs was dried at 70˚C for 48
hours and had an average weight loss of 44.8 ± 1.5%, which was then applied to remaining
shrubs to calculate total dried weights. The aboveground biomass of herbs and shrubs for each
plot was calculated by dividing mean biomass by quadrat area. Root biomass was not measured,
so total herb biomass was calculated as 3 times herb aboveground biomass and total shrub
biomass as 2.5 times shrub aboveground biomass (Johnston et al., 2002; Sherman & Beckett,
2003). Herb C and shrub C pools were calculated by multiplying total herb biomass by 0.45
(Sherman & Beckett, 2003; Vogel & Gower, 1998) and total shrub biomass by 0.48 (Foster &
Morrison, 2002; Johnston et al., 2002; Sherman & Beckett, 2003).
Tree C storage
Trees were defined as any self-supporting, standing biomass with a DBH ≥ 3 cm. All
trees within each plot were surveyed for species, health status (living or decay class 1-5), and
DBH. The number of jack pine per plot was recorded to indicate jack pine frequency. CBM-
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CFS3 DBH-based biomass equations from Lambert et al. (2005) were used for balsam poplar
(Populus balsamifera), eastern hemlock (Tsuga canadensis), eastern white pine (Pinus strobus),
largetooth aspen (Populus grandidentata), jack pine, red maple (Acer rubrum), red oak
(Quercus rubra), and red pine (Pinus resinosa). Some species were updated for CBM-CFS3 in
Ung et al. (2008), so these equations were used for trembling aspen (Populus tremuloides), white
birch, white spruce (Picea glauca), and unknown deciduous trees that were too decayed to ID.
Willow (Salix spp.) and cherry (Prunus spp.) trees were not identified to species, so unknown
deciduous tree equations were again used (Ung et al., 2008). DBH-based biomass equations were
used to calculate total aboveground tree biomass:
where yi is the dry mass (kg) of compartment i (wood, bark, stem, foliage, branches, or crown),
βi are parameters outlined in Lambert et al. (2005) and Ung et al. (2008), D is the tree DBH (cm),
Ȳi is the modeled value of yi, and ei is the error term for compartment i (Table A1, Table A2)
(Lambert et al., 2005; Ung et al., 2008). Tree C was initially calculated using both CBM-CFS3
equations and allometric equations from Sherman (2005), which included Sudbury-specific
equations for some tree species. Tree C values from both calculations were found to be similar,
so I used CBM-CFS3 equations in my final dataset to make my data more comparable to other
studies.
Belowground tree biomass was estimated at 20% of aboveground tree biomass, so total
tree C was calculated by multiplying aboveground biomass (WA ) by 1.2 (Sherman & Beckett,
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2003), decay-class reduction factor (DCRF), structural reduction factor (SRF), and a C
concentration of 48% (Foster & Morrison, 2002; Russell et al., 2015; Sherman & Beckett, 2003):
(5) Tree C (Mg C ha-1) = 1.2 * WA * DCRF *SRF * 0.48
where DCRF values were from Harmon et al. (2011) and SRF values from Domke et al. (2011).
Martin et al. (2018) found tree C concentrations in temperate forests to be 46.5 ± 0.3% for
angiosperms and 50.1 ± 0.4% for conifers, and in boreal forests 49.2 ± 0.8% for angiosperms and
46.8 ± 0.6% for conifers. Therefore, a tree C concentration of 48% for angiosperms and conifers
in a boreal mixed forest was appropriate. I summed individual tree C values for each plot to
calculate final tree C.
Plant species richness
Species richness for trees, shrubs, and herbs was calculated by counting the number of
unique species in each plot. I calculated total plant species richness by summing the species
richness of the three vegetative layers.
Soil chemistry and C storage
Total depths of mineral and organic (LFH) soil were measured at 16 points along
transects, to a maximum depth of 20 cm (Fig. 2.2). Soil samples were collected at every other
sampling point (Fig. 2.2). A 10 cm diameter metal punch was used to sample and measure the
depth of the organic soil (Fig. 2.3). A 2.5 cm diameter soil auger was used to sample mineral soil
at 0-5 cm, 5-10 cm, and 10-20 cm depths (Fig. 2.3).
Soil samples were oven-dried at 60˚C for 16 hours and weighed. Soils were then
homogenized and passed through a 2 mm sieve. The pH of all homogenized soil samples was
taken with an Accumet AB150 pH meter with a 2:1 ratio of milli-Q to soil that was shaken and
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then let settle. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure
total and bioavailable metal and nutrient concentrations in soil samples. All samples were
processed at the Elliott Lake Research Field Station laboratory at Laurentian University using a
multi-acid (HF/HCl/HNO3) 90 °C open-block digest for total metals and a weak (0.01M) LiNO3
extraction procedure for bioavailable metals (Abedin et al., 2012). Soil samples from the 0-5 cm
layer were pooled for each plot and sampled using cone-splitting (poured into a cone-shaped pile
and cut into even triangular slices). Bioavailable metal concentrations were sampled by cone-
splitting into 8 sections and weighing the section on the far-left of the pile to 3 g. Duplicates
were randomly chosen for every 10 samples, and a blank was run prior to every 20 samples.
Total metals were measured by further cone-splitting existing soil piles into 16 sections,
sampling the far-right section, and weighing out 0.5 g. Elements identified in the SARA Group
(2009) study as chemicals of concern (COC) for the Sudbury region (As, Co, Cu, Pb, Ni, Se, Cd)
were the focus of my study. Concentrations below detection limits were set at half of detection
limit. Total soil COC concentrations were compared to limits for uncontaminated soils for
residential, industrial, and park sites listed in Table 1 of Ontario Ministry of the Environment
Conservation and Parks (2011). Quality assurance and quality control (QAQC) of ICP-MS’s
analytical and method precision was analyzed by comparing the relative percent difference
between laboratory and sample duplicates for each element (Table A3). Known concentration
CRM TILL-1 data were compared to my samples, however my samples were digested with HF
while CRM standards were not, so they were not directly comparable.
Loss on ignition (LOI) was used to determine the soil organic matter (SOM) content of
all samples. Sub-samples of homogenized soils were weighed, combusted at 550˚C for 5 hours in
a muffle furnace, and re-weighed. Bulk density was calculated as the mass of the sieved soil
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(excluding rocks that did not pass through the 2 mm sieve) divided by the volume of the soil core
for that layer.
Stored soil C was calculated by dividing SOM by the SOM:SOC ratio, multiplying it by
bulk density (BD) and each layer’s across-plot volume (V), and dividing it by 0.1 ha:
(6) Mineral soil C (Mg C ha-1) = SOM/ 2.114 * BD * V/ 0.1
(7) Organic soil C (Mg C ha-1) = SOM/ 2 * BD * V/ 0.1
I used a Sudbury-specific SOM:SOC ratio for mineral soils of 47.3% (conversion factor of
2.114) (Sherman, 2005) and a SOM:SOC ratio of 50% (conversion factor of 2) for organic soil
(Nelson & Sommers, 1996; Sherman, 2005; Smithwick et al, 2002). Organic C was presumed to
equal total C because in non-calcareous soil regions, such as Sudbury, soil contains negligible
non-organic C (Périé & Ouimet, 2011). My methods only measured soil C to a maximum depth
of 20 cm, which excluded deep mineral soil in some sites. However, Sudbury’s soils are
generally thin with large areas of surficial bedrock, so a maximum depth of 20 cm incorporated
most mineral soil.
Wetness index
Wetness index is the relative moisture of soil, vegetation, and other moist features that is
calculated by comparing the absorbance and reflectance of different wavelengths from satellite
imagery (Baig et al., 2014). I calculated wetness index using Landsat8 OLI data, with resolution
of around 30 m2, that I acquired from the USGS for July 17, 2018. The imagery was chosen
based on quality and the date coinciding with field work. R version 3.4.1 was used to plot and
crop the raster files. Upland industrial barren plot centre coordinates were overlaid onto the
Landsat cropped raster, and a 17.84 m buffer was superimposed around each point to indicate
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plot boundaries (Fig. A1). Mean tasseled cap wetness index values were calculated for each plot
using the “tasseledCap” R package (Baig et al., 2014) and standardized with z-scores for
comparison.
Distance from smelter
ArcMap (10.6.1) was used to calculate the distance from the Coniston smelter to each
upland plot centre-point, with the smelter reference point set at half-way between the two
smokestacks.
Data analysis
Total plot C storage (Mg C ha-1) was calculated by summing the C stored in CWD, FWD,
herbs, organic soil, mineral soil (to a maximum depth of 20 cm), shrubs, and trees. Plots were
divided into upland industrial barrens (≥ 280 m) and lowland valleys (˂ 280 m) based on their
centre-point elevations. A cut-off of 280 m was chosen because tree-planting only occurred
above this altitude.
R 3.6.0 (64-bit) was used for all statistical tests. Data were tested for normality across all
treatments. A two-tailed t-test was used to compare limed, fertilized, and seeded plots (L) and
untreated plots (U) in lowland valley plots. An ANOVA with a significance level of 0.05 was
used to test differences in total C storage among treatments (U, L, T, L+T) in upland industrial
barrens. Tukey’s HSD was used as post-hoc test to determine what treatments were significantly
different from each other for upland industrial barrens.
Multiple linear regression was used to determine what site characteristics most affected
plot C storage in upland industrial barrens. A principal component analysis (PCA) for
bioavailable metals (chemicals of concern) in upland industrial barren sites was conducted,
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including bioavailable concentrations of As, Cd, Co, Cu, Ni, and Pb (SARA Group, 2009). Se
was also listed as a Sudbury chemical of concern, but it was not included in my analysis because
all bioavailable concentrations were below the detection limit. (SARA Group, 2009). A broken-
stick analysis was used to determine how many principal components (PCs) to include in my
linear model. The broken-stick model designated that observed eigenvalues that exceeded
broken-stick model-generated eigenvalues were significant and should be included in the model
(Jackson, 1993). In my study only PC1 fit this criterion and was included in my linear regression
(Fig. A2, Table A6). I then conducted a Pearson correlation analysis to ensure that no predictor
variables in my linear regression were highly correlated to each other (correlation coefficient ≥
0.75) (Table A4). I also used a Pearson correlation matrix to see what predictors were
significantly correlated to C storage and each other (Table A5). Wetness index, plant species
richness, PC1 (soil bioavailable metals), soil pH (0-5 cm mineral soil), jack pine frequency,
distance from smelter, and elevation were all selected for potential inclusion in the linear
regression. Interactions between predictors were tested but not included in the final model
because they were not significant. Backwards linear regression was used to compare all possible
models and select the top model based on Second-order Akaike’s Information Criterion (AICc),
which was utilized because it was more robust with relatively small sample sizes and multiple
parameters. All variables were standardized using z-scores with the equation:
(8) y = (yi - ymean)/SD
where z-scores had a mean of 0 and a standard deviation (SD) of 1. Final variables included in
the linear regression were wetness index, plant species richness, PC1 (soil bioavailable metals),
soil pH, jack pine frequency, distance from smelter, and elevation.
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Figure 2.1 Map of Daisy Lake watershed plots in upland industrial barrens (> 280 m centre
elevation) (n = 32) and lowland valleys (≤ 280 m centre elevation) (n = 13). Shading indicates
tree-planted (T), limed, fertilized, and seeded (L), and limed, fertilized, and seeded + tree-planted
(L+T) treatments. Untreated (U) areas are not shaded. Daisy catchments H, I, and J are labelled.
Arrow indicates direction of historic Coniston smelter.
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Figure 2.2 Layout of sampling points at each 0.1 ha plot. FWD-1 through FWD-4 were LIS
locations for FWD survey. Soil depth was measured at 1-16, while soil samples were taken at
even numbers only. Understory sampling occurred in 1 m2 square quadrats located at numbers 4,
8, 12, and 16. All other sampling occurred throughout entire plot.
Figure 2.3 Soil sampling protocols for organic and mineral soil layers. Mineral soil was divided
into 3 depths (0-5 cm, 5-10 cm, 10-20 cm) and sampled with a1.5 cm diameter soil corer and
organic soil was collected using a 5 cm circular frame.
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3.0 Results
Effect of treatment on C storage
In upland industrial barrens the mean total ecosystem C pool was 36.1 ± 8.4 Mg C ha-1
for U plots, 34.2 ± 8.6 Mg C ha-1 for L plots, 47.6 ± 4.2 Mg C ha-1 for T plots, and 58.2 ± 4.4 Mg
C ha-1 for L+T plots (Fig. 3.1). Total C storage among treatments was significantly different (F
(3,28) = 3.8, p < 0.05), with L+T plots storing significantly more C than L plots (p < 0.05) (Fig.
3.1).
In lowland valleys with deeper soils and more natural regeneration of tree cover, total
ecosystem C storage was significantly greater (t(21) = -4.95, p < 0.0001) than in the uplands area.
Liming in lowland valleys further increased (t(7) = 3.5, p < 0.01) the total C stores compared to
untreated plots from 73.3 ± 5.9 Mg C ha-1 to 101.1 ± 5.5 Mg C ha-1 (Fig. 3.5). Mineral soil C
(39.7%) and tree C (34.5%) were the largest contributors to total ecosystem C storage in lowland
valleys.
C pools: Upland industrial barrens
In upland industrial barrens, the main focus of my study, mineral soil was the largest C
pool in all treatments but did not differ significantly among treatments (p > 0.05) (Fig. 3.2).
Mineral soil C stored 69.6% of C in U plots, 64.4% in L plots, 51.1% in T plots, and 45.9% in
L+T plots. Tree C was significantly different among treatments (F (3,28) = 39.6, p < 0.001). Tree
C pools in T plots (13.0 ± 0.8 Mg C ha-1) and L+T plots (19.3 ± 1.4 Mg C ha-1) were
significantly larger than tree C pools in L plots (2.8 ± 1.8 Mg C ha-1) and U plots (0.5 ± 0.4 Mg
C ha-1) (p < 0.01), and L+T plots also had significantly more tree C than T plots (p < 0.01) (Fig.
3.2). Tree C stored 1.4% of total ecosystem C in U plots, 8.1% in L plots, 27.3% in T plots, and
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33.1% in L+T plots. Organic soil C was not significantly different among treatments (p > 0.05)
(Fig. 3.2), contributing 18.8% of C storage in U plots, 16.9% in L plots, 12.1% in T plots, and
14.5% in L+T plots. Herb C was not significantly different among treatments (p > 0.05) (Fig.
3.2), storing 7.3% of total C in U plots, 7.2% in L plots, 3.8% in T plots, and 2.9% in L+T plots.
Shrub C was not significantly different among treatments (p > 0.05) (Fig. 3.2), storing 2.1% of
total C in U plots, 2.8% in L plots, 4.7% of C in T plots, and 3.0% in L+T plots. Neither FWD
nor CWD stored significantly different amounts of C among treatments (p > 0.05) (Fig. 3.2) and
both were relatively small C pools, storing < 1% of total C across all treatments.
Predictors of C storage: Upland industrial barrens
The wetness index was the strongest predictor of total C storage at the uplands sites,
followed by plant richness and a principal component index composed of the bioavailable
concentration of metals (As, Cd, Co, Cu, Ni, Pb) considered as chemicals of concern in the
Sudbury area. Together these metrics in a linear regression model explained 64.0% of the
variance in C storage (Table 3.1.)
No other model had ∆AICc < 2, meaning that the top model had considerable support.
Wetness index had the largest coefficient (11.27 ± 2.40) and explained 53.5% of the variance,
followed by plant richness (6.11 ± 2.58; 6.4%), and PC1 (-3.57 ± 1.45; 3.0%) (Table 3.1).
Wetness index (z-scores) increased significantly (p < 0.001) from -1.22 ± 0.42 in U plots
to 0.59 ± 0.17 in L+T plots (Fig. 3.3). T plots also had significantly higher wetness indices (p <
0.01; 0.30 ± 0.15) than U plots (Fig. 3.3). Furthermore, L+T plots also had significantly higher
wetness than L plots, which had a wetness index of -0.49 ± 0.45 (p < 0.05) (Fig. 3.3).
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Plant species richness increased significantly (p < 0.001) from U plots (9.40 ± 1.17) and
T plots (10.50 ± 0.57) to L+T plots (18.42 ± 1.09) (Fig. 3.4). L plots also had significantly higher
(p < 0.05) plant species richness (15.71 ± 2.34) than U plots (Fig. 3.4).
Mineral soil bioavailable metal concentrations varied among restoration treatments,
however, there was no clear pattern between bioavailable metals and restoration treatment (Fig.
A4). Total concentration of these metals of concerns were used for comparison to provincial
standards, as there were no provincial standards for bioavailable soil concentrations. Total
mineral soil As, Cd, Cu, Ni, and Se concentrations for all treatments were above provincial
standards for soils in residential, parkland, institutional, commercial, or community property use
(Fig. A3) (Ontario Ministry of the Environment Conservation and Parks, 2011). Total mineral
soil Co and Pb concentrations for all treatments were below the provincial limits (Fig. A3).
Mineral soil pH
Soil pH varied by treatment in upland barrens; U plots had mean mineral soil pH values
that ranged between 4.1 – 4.5, L plots between 4.5 – 6.5, T plots between 4.1 – 4.5, and T+L
plots between 4.4 – 5.6 (Table A8). Lowland valley L plots had mean mineral soil pH values that
ranged between 4.5 – 5.4 and U plots between 3.7 – 4.6 (Table A8).
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Figure 3.1 Total ecosystem C storage (Mg C ha-1 ± SE) in upland industrial barrens
among untreated (U), limed, fertilized, seeded (L), tree-planted (T), and limed, fertilized,
seeded + tree-planted (L+T) plots (n = 32 plots). Different letter designations above bars
indicate significant differences at p < 0.05.
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Figure 3.2 C storage (Mg C ha-1 ± SE) in each C pool (CWD, FWD, herb, mineral soil, organic
soil, shrub, and tree) in upland industrial barrens among untreated (U), limed, fertilized, seeded
(L), tree-planted (T), and limed, fertilized, seeded + tree-planted (L+T) plots (n = 32 plots).
Different letter designations in tree C indicate significant differences at p < 0.05. Only tree C
differed significantly by treatment.
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Figure 3.3 Wetness index (z-scores) in upland industrial barrens among untreated (U), limed,
fertilized, seeded (L), tree-planted (T), and limed, fertilized, seeded + tree-planted (L+T) plots (n
= 32 plots). Different letter designations above plots indicate significant differences at p < 0.05.
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Figure 3.4 Plant species richness (± SE) in upland industrial barrens among untreated (U),
limed, fertilized, seeded (L), tree-planted (T), and limed, fertilized, seeded + tree-planted (L+T)
plots (n = 32 plots). Different letter designations above bars indicate significant differences at p
< 0.05.
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Table 3.1 Linear regression relating total ecosystem C storage (Mg C ha-1) in upland industrial
barren plots (n = 32 plots) to wetness index, plant species richness, PC1 (first axis of principal
component of soil bioavailable [As], [Cd], [Co], [Cu], [Ni], [Pb]), soil pH, jack pine frequency,
distance from smelter, and elevation (MASL). Model was generated using backward selection
with second order Akaike Information Criterion (AICc).
Final model:
C storage ~ Wetness index + Plant richness + PC1
Wetness index
Plant richness
PC1
Estimate (SE)
11.27 (2.40)
6.11 (2.58)
-3.57 (1.45)
p value
<0.001
<0.05
<0.05
AICc= 257.83
Intercept= 46.86
R2= 0.64
p value < 0.001
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Figure 3.5 Total ecosystem C storage (Mg C ha-1 ± SE) at lowland valley untreated (U) and
limed, fertilized, seeded (L) plots (n = 13). Different letter designations above bars indicate
significant differences at p < 0.01.
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4.0 Discussion
C storage: Upland industrial barrens
Overall the restoration treatment in the uplands showed benefits in terms of tree C
accumulation in the time period of this study. The fully treated sites had 61% more C than the
untreated sites, but presumably because of the high variability among the sites, the differences
were not yet significantly different. This slow accumulation of C may be because the jack pine
were planted only 17-21 years prior to my study and jack pine continue to grow and reproduce
until 60-100 years of age (Wisconson Department of Natural Resources, 2016). This means that
the restored forests were not fully mature, but are expected to continue to grow, reproduce, and
sequester C in this industrial barren into the future. The rate of accumulation is uncertain because
of the very challenging soil and moisture conditions that exist in the upland barrens area.
A previous Sudbury study assessed C storage in restored barrens and found significantly
increased total ecosystem C storage in tree-planted + limed plots compared to untreated plots 23
years post-restoration (Sherman & Beckett, 2003). Sherman and Beckett (2003) found that
unrestored industrial barrens stored 35.5 ± 6.5 Mg C ha-1, which was very similar to the C
storage in my naturally regenerating upland barren sites (36.1 ± 8.4 Mg C ha-1). These results
indicate that over the 16 years between C quantification in Sherman and Beckett (2003) and my
study, negligible C was sequestered through natural regeneration of Sudbury’s industrial barrens.
Furthermore, Sherman and Beckett (2003) found that sites restored with liming and tree-planting
increased C storage by 200% (106.5 ± 6.2 Mg C ha-1), while I did not find a significant increase
in total C storage with restoration. Natural regeneration in untreated plots was limited by poor
site conditions that impeded plant and soil development. Some of these factors included drought
conditions, soil metals, wind cooling, direct solar radiation, and erosion (Winterhalder, 1995).
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Planting trees and adding soil amendments somewhat mitigated these issues, facilitating tree
growth and C storage (Winterhalder, 1996). My restored sites’ total C storage values were
relatively low, but within the range given in Hazlett et al. (2005) (28.3 – 135.1 Mg C ha-1) for
upland boreal forests. Forest recovery and C storage was constrained on my site by the relatively
harsh growing conditions even following restoration treatments. I do, however, expect that my
restored sites will sequester C at a faster rate than untreated sites, perhaps eventually finding a
significant difference in total C storage between untreated and fully restored sites and reaching
the C storage of restored sites in Sherman and Beckett (2003). With almost 15,000 – 20,000 ha
of Sudbury’s industrial barrens still to be restored (P. Beckett personal communication, Dec. 19,
2019), Sudbury therefore still has significant potential to increase the C storage of these barrens
across all C pools. Restoration treatments and site conditions will determine the rate of C
sequestration and the magnitude of total C storage.
Tree C pools were larger in restored than untreated plots. Tree C was largest in plots that
were limed, fertilized, seeded, and tree-planted, demonstrating the benefit of reforestation paired
with soil amendments in acidified and metal-polluted soils. Reforestation directly increases tree
C by increasing tree biomass (Griscom et al., 2017). Liming increases soil pH and reduces the
bioavailability of acidity-dependent trace metals, while fertilizing provides plant nutrients (Bolan
et al., 2003; Lal, 2005). Therefore, a combination of liming, fertilizing, seeding, and tree-
planting increased tree C storage on my plots. Restoration was also expected to increase herb and
shrub biomass, but this was not the case in my study. It is possible that the increased tree canopy
subjected understory plants to light competition, which decreased their biomass (Burton et al.,
2013).
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I expected that mineral soil C storage would increase in restored sites compared to
untreated sites, however mineral soil C was not affected by restoration treatments. My study
found that mineral soil was the largest C pool in all treatments. Most boreal forests store the
majority of C in mineral soil, so this C pattern was expected (DeLuca & Boisvenue, 2012).
Mineral soil is relatively stable and well protected from disturbance-derived decomposition, so
sequestering C in mineral soil is beneficial for long term C storage (Vesterdal et al., 2013). I also
expected that organic soil C storage would be affected by restoration, however, this did not occur
in my study. Other studies have found that soil liming caused a net loss in soil C by increasing
pH and facilitating microbial decomposition of SOM (Haynes & Naidu, 1998). Lime was applied
24 years prior to my study, so lime-induced decomposition could have affected both the mineral
and organic soil layers in earlier years. Furthermore, physical soil movement during tree-planting
or continued erosion could have decreased soil aggregation and bulk density, reducing soil C
(Nave et al., 2013). Afforestation could have also affected soil C through soil disturbance,
increased SOM mineralization, and increased litterfall inputs (Jandl et al., 2007). Therefore,
liming likely increased soil turnover rates, resulting in unchanged soil C pools between restored
and untreated plots. Other studies have found that mine-impacted soils started to accumulate
significant soil C 15-25 years post-planting (Nave et al., 2013). My study looked at forests
planted 17-24 years prior and limed, fertilized, and seeded 21-24 years prior, so we may just now
be entering a period where increasing soil C sequestration is expected. However, thin, rocky
soils, high metal concentrations, and limited moisture may continue to limit C storage in these
particular industrial sites for many years to come.
Additionally, I expected that restoration would increase downed woody debris C storage
in upland industrial barrens, but I found no significant difference in CWD or FWD C storage
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across treatments. Downed woody debris usually comprises around 20% of total C storage in
mature forest ecosystems (Russell et al., 2015). In contrast my study found that CWD and FWD
only represented < 1% of total C. Downed woody debris C pools increase with forest age (Keith
et al., 2009), so depauperate downed woody debris C pools might have been due to the forest’s
young age. Furthermore, liming could have reduced downed woody debris C pools by
stimulating microbial decomposition of downed wood (Jandl et al., 2007). Afforestation also
increased the canopy cover, which could have affected downed woody debris decomposition by
increasing site moisture and reducing temperature extremes (Forrester et al., 2012).
Predictors of C storage
Wetness index was the best predictor of total ecosystem C storage in my study.
Sudbury’s landscapes had variable microtopography (i.e., elevation, aspect, and slope) that
created spatially varied soil wetness (Moeslund et al., 2013; Winterhalder, 1996). Soil wetness
controls vegetative growth by buffering soil temperatures, fulfilling water requirements, and
affecting nutrient availability (Moeslund et al., 2013). Tree-planting, liming, fertilizing, and
seeding likely increased soil wetness, as restoration protects against wind desiccation, prevents
drought-inducing temperature extremes, and increases soil moisture retention (Winterhalder,
1996). Areas with high wetness index values were in depressions and likely received soil erosion
inputs, were protected from wind erosion, were buffered from temperature extremes, and had
higher seed accumulation (Moeslund et al., 2013). Areas with low wetness index values were
mainly flat ridgetops with extreme temperatures, drought conditions, frost stress, high erosion
potential, and little seed accumulation, which resulted in reduced C storage (Moeslund et al.,
2013; Winterhalder, 1996).
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Plant species richness was also a significant predictor of total ecosystem C storage.
Limed plots had significantly more plant species than un-limed plots. Forest diversity generally
increases plant C storage through niche portioning, increased stem density and production, and
enhanced soil fertility (Mensah et al., 2016).
I found that legacy metals from the smelter had a negative effect on total ecosystem C
storage. Most total metal concentrations more than 40 years after the smelter closed were still
above provincial soil standards (Fig. A3, Fig. A4). High concentrations of trace metals
negatively impact plant growth (Barrett & Watmough, 2015). Metal bioavailability is affected by
soil acidity, nutrient availability, and SOM content (Bolan et al., 2003; Meadows & Watmough,
2012). Therefore, I expected that tree-planting, liming, seeding, and fertilizing would impact
metal bioavailability. Restoration treatments, however, did not consistently affect bioavailable
metal concentrations. This could be because metals had differing adsorption acidity thresholds,
responses to SOM inputs, and interactions with Ca and Mg in dolomitic limestone (Bolan et al.,
2003).
C storage: Lowland valleys
Although it was not my initial focus because the full restoration efforts were confined to
the uplands, it was clear that topography had a very large effect on C storage. Lowland sites
showed improved C storage with liming, but even the untreated lowland sites had higher C
storage than the fully treated upland sites. This could be because valleys contained refugial
vegetation, were protected from smelting pollution, and received erosion inputs (Vanttinen,
1993; Winterhalder, 1995). Lowland valley limed, fertilized, and seeded plots had significantly
increased C storage compared to untreated plots. Soil amendments and seed distribution might
have bolstered productivity and increased C storage. Furthermore, an uneven sample size (L = 3,
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U = 10) could have exasperated site differences among treatments. Two lowland valley limed,
fertilized, and seeded plots were at the base of steep cliffs with ephemeral standing water, which
could have enhanced plant growth, reduced decomposition, and increased C storage.
Restoration recommendations
I recommend that industrial barrens continue to be treated with tree-planting, liming,
fertilizing, and seeding, as this increased tree C storage in my study. Industrial barrens have poor
plant growth conditions, so natural regeneration is slow (Ketchledge et al., 1985; Winterhalder,
1996). Restoring industrial barrens promotes regeneration by reducing acidity and trace metal
bioavailability, preventing temperature extremes, buffering wind, and binding soil (Winterhalder,
1996). Therefore, liming, fertilizing, seeding, and tree-planting industrial barrens is expected to
create slow but still effective C accumulation and storage.
The addition of an organic amendment (i.e., mulch) to the restoration protocol might
further increase C storage by increasing soil moisture. Additionally, I would recommend a
diverse planting regime rather than a monoculture plantation. Monocultures store less C than
mixed forests (Jandl et al., 2007). I would also recommend planting N-fixing trees species, such
as alder (Alnus sp.) and black locust (Robinia pseudoacacia L.), as they increase soil C
concentrations by 20-100% (Johnson, 1992; Vesterdal et al., 2013). Boreal forests generally have
higher organic and mineral soil C stocks under conifers than deciduous trees, so planting
coniferous trees would also promote C storage (Vesterdal et al., 2013).
I further recommend that naturally regenerated lowland valleys also be treated with
limestone, fertilizer, and seed to further enhance plant development and C storage.
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Limitations of study
In my study soils were generally very thin and my mineral soil C was only measured to a
maximum depth of 20 cm, while other studies indicate that boreal forests can store C in mineral
soil up to 1 m deep (DeLuca & Boisvenue, 2012). Many of my industrial barren plots had in total
less than 20 cm of mineral soil, however. Forests generally sequester C over time, so repeating
my study in another 10 years could find significant C sequestration trends. In addition to the soil
limitations, drought during the 2018 growing season also could have impacted C storage results.
Some vegetation prematurely senesced during my study, which could have impacted understory
biomass and litterfall rates. Finally, some white birch, red maple, and red oak in my study were
stunted with coppiced growth forms, while the DBH-based biomass equations were designed for
single-stemmed, healthy trees. However, I did initially compare my tree C calculations to the
allometric equations in Sherman (2005) and both sets of equations produced very similar values,
so the discrepancies would be minimal. I am uncertain if these possible errors would have had
any substantial effects.
Furthermore, I have used the boreal forest for comparisons throughout, while Sudbury is
on the ecotone of the Great Lakes – St. Lawrence and boreal forests. The restored sites I assessed
contained more boreal species (i.e., jack pine, red pine, white spruce, trembling aspen, white
birch) than Great Lakes – St. Lawrence species (i.e., red oak, red maple), so the boreal forest was
more comparable. Additionally, boreal forest literature is commonly used for comparison in
other Sudbury studies. However, with climate change, future Sudbury forest composition might
be better compared to Great Lakes – St. Lawrence forest types.
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Conclusion
Restoration of industrial barrens on upland sites with a combination of tree-planting,
liming, fertilizing, and seeding increased tree C storage during a 24-year period, but total C
storage was not yet significantly higher than in untreated sites. C accumulation is a slow process
in such challenging sites, resulting in slower C sequestration rates and C storage than in most
boreal forest sites. Mineral soil was the largest C pool in all treatments but was unaffected by
restoration. Tree C increased significantly in the restored plots, while CWD, FWD, herbs,
organic soil, and shrubs were all unaffected by restoration. Wetness index, plant species richness,
and soil metal contamination all appeared to affect C storage, with wetness index the most
important factor. Therefore, it is important to consider site characteristics when planning
restoration to maximize C storage in industrial barrens. For example, I found that C storage in
naturally regenerated lowland valleys was significantly increased with liming, fertilizing, and
seeding. From a global perspective, it is important to recognize that industrial barrens are
estimated to cover millions of hectares (Gunn et al., 1995; Kozlov & Zvereva, 2015). Restoration
of industrial barrens in my study was found to increase tree C storage on a site with poor
growing conditions. Continued growth and C accumulation across all C pools in these restored
forests is expected, which suggests that largescale restoration practices in industrial barrens
could add to terrestrial C pools and contribute to climate change mitigation.
Future studies
I suggest that future studies assessing C storage in restored industrial barrens include
several local reference plots with comparable site characteristics (i.e., elevation, slope, geology,
aspect, climate) in areas that were not industrially-disturbed. This would allow a comparison
between similar restored and undisturbed areas to determine the difference in C storage at a local
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scale. I would also suggest increasing the sample size for each treatment and having an equal
number of replicates per treatment. Repeated sampling over time of my current study sites is also
important. Future studies should also incorporate detailed microtopography data as potential
drivers of total ecosystem C storage. Heterogeneous landscapes, such as Sudbury, are difficult to
characterize at large scales, so remote sensing, such as LiDAR, would be useful for site
characterization. Finally, I recommend that location-specific biomass equations be constructed
for each tree species, which would ensure that tree C storage is accurately measured based on
local tree growth forms.
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REFERENCES
Abedin, J., Beckett, P., & Spiers, G. (2012). An evaluation of extractants for assessment of metal
phytoavailability to guide reclamation practices in acidic soilscapes in northern regions.
Canadian Journal of Soil Science, 92(1), 253–268. https://doi.org/10.4141/CJSS2010-061
Amiro, B. D., Barr, A. G., Barr, J. G., Black, T. A., Bracho, R., Brown, M., … Xiao, J. (2010).
Ecosystem carbon dioxide fluxes after disturbance in forests of North America. Journal of
Geophysical Research: Biogeosciences, 115(4). https://doi.org/10.1029/2010JG001390
Amiro, B. D., & Courtin, G. M. (1981). Patterns of vegetation in the vicinity of an industrially
disturbed ecosystem, Sudbury, Ontario. Canadian Journal of Botany, 59(9), 1623–1639.
https://doi.org/10.1139/b81-221
Baig, M. H. A., Zhang, L., Shuai, T., & Tong, Q. (2014). Derivation of a tasselled cap
transformation based on Landsat 8 at-satellite reflectance. Remote Sensing Letters, 5(5),
423–431. https://doi.org/10.1080/2150704X.2014.915434
Barrett, S. E., & Watmough, S. A. (2015). Factors controlling peat chemistry and vegetation
composition in Sudbury peatlands after 30 years of pollution emission reductions.
Environmental Pollution, 206, 122–132. https://doi.org/10.1016/j.envpol.2015.06.021
Beckett, P., & Negusanti, J. (1990). Using land reclamation practices to improve tree condition
in the Sudbury smelting area, Ontario, Canada. Proceedings of the 1990 Mining and
Reclamation Conference and Exhibition., 307–320. https://doi.org/10.21000/jasmr90010307
Bengtsson, B., Asp, H., Jensén, P., & Berggren, D. (1988). Influence of aluminium on phosphate
and calcium uptake in beech (Fagus sylvatica) grown in nutrient solution and soil solution.
Physiologia Plantarum, 74(2), 299–305. https://doi.org/10.1111/j.1399-
3054.1988.tb00635.x
Bolan, N. S., Adriano, D. C., & Curtin, D. (2003). Soil acidification and liming interactions with
nutrientand heavy metal transformation and bioavailability. Advances in Agronomy, 78,
215–272. https://doi.org/10.1016/S0065-2113(02)78006-1
Bradshaw, C. J. A., Warkentin, I. G., & Sodhi, N. S. (2009). Urgent preservation of boreal
carbon stocks and biodiversity. Trends in Ecology and Evolution, 24(10), 541–548.
https://doi.org/10.1016/j.tree.2009.03.019
Burton, J. I., Ares, A., Olson, D. H., & Peuttmann, K. J. (2013). Management trade-off between
aboveground carbon storage and understory plant species richness in temperate forests.
Ecological Applications, 23(6), 1297–1310.
Carmichael, H. (2018, September 14). Vale celebrates complete of emission reduction project.
The Sudbury Star. Retrieved from https://www.thesudburystar.com/news/local-news/vale-
celebrates-completion-of-emissions-reduction-project
City of Greater Sudbury. (2018). Regreening Program: 2018 Annual Report. Retrieved from
https://www.greatersudbury.ca/live/environment-and-sustainability1/regreening-program/
City of Greater Sudbury. (2019). Sudbury Regreening (App). Retrieved May 9, 2019, from
![Page 49: Effects of Restoration on Carbon Storage in Smelter ......2010/01/06 · part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or,](https://reader036.fdocuments.in/reader036/viewer/2022081613/5fb4c7298cdd7e784b7bc233/html5/thumbnails/49.jpg)
39
https://sudbury.maps.arcgis.com/apps/webappviewer/index.html?id=73fcef8187864784a3a6
aad98eb9c1ba
DeLuca, T. H., & Boisvenue, C. (2012). Boreal forest soil carbon: Distribution, function and
modelling. Forestry, 85(2), 161–184. https://doi.org/10.1093/forestry/cps003
Dixit, A. S., Dixit, S. S., & Smol, J. P. (1996). Setting restoration goals for an acid and metal-
contaminated lake: A paleolimnological study of daisy lake (Sudbury, Canada). Lake and
Reservoir Management, 12(3), 323–330. https://doi.org/10.1080/07438149609354274
Domke, G. M., Woodall, C. W., & Smith, J. E. (2011). Accounting for density reduction and
structural loss in standing dead trees: Implications for forest biomass and carbon stock
estimates in the United States. Carbon Balance and Management, 6, 1–11.
https://doi.org/10.1186/1750-0680-6-14
Flannigan, M. D., Amiro, B. D., Logan, K. A., Stocks, B. J., & Wotton, B. M. (2005). Forest
fires and climate change in the 21st century. Mitigation and Adaptation Strategies for
Global Change, 11(4), 847–859. https://doi.org/10.1007/s11027-005-9020-7
Forrester, J. A., Mladenoff, D. J., Gower, S. T., & Stoffel, J. L. (2012). Interactions of
temperature and moisture with respiration from coarse woody debris in experimental forest
canopy gaps. Forest Ecology and Management, 265, 124–132.
https://doi.org/10.1016/j.foreco.2011.10.038
Foster, N. W., & Morrison, I. K. (2002). Carbon sequestration by a jack pine stand following
urea application. Forest Ecology and Management, 169(1–2), 45–52.
https://doi.org/10.1016/S0378-1127(02)00297-9
Fraver, S., Ringvall, A., & Jonsson, B. G. (2007). Refining volume estimates of down woody
debris. Canadian Journal of Forest Research, 37(3), 627–633. https://doi.org/10.1139/x06-
269
Freedman, B., & Hutchinson, T. C. (1980). Effects of smelter pollutants on forest leaf litter
decomposition near a nickel–copper smelter at Sudbury, Ontario. Canadian Journal of
Botany, 58(15), 1722–1736. https://doi.org/10.1139/b80-200
Gao, B., Taylor, A. R., Searle, E. B., Kumar, P., Ma, Z., Hume, A. M., & Chen, H. Y. H. (2017).
Carbon storage declines in old boreal forests irrespective of succession pathway.
Ecosystems, 21(6), 1168–1182. https://doi.org/10.1007/s10021-017-0210-4
Giesler, R., Satoh, F., Ilstedt, U., & Nordgren, A. (2004). Microbially available phosphorus in
boreal forests: Effects of aluminum and iron accumulation in the humus layer. Ecosystems,
7(2), 208–217. https://doi.org/10.1007/s10021-003-0223-z
Gower, S. T., Krankina, O., Olson, R. J., Apps, M., Linder, S., & Wang, C. (2001). Net primary
production and carbon allocation patterns of boreal forest ecosystems. Ecological
Applications, 11(5), 1395–1411. https://doi.org/10.1890/1051-
0761(2001)011[1395:NPPACA]2.0.CO;2
Griscom, B. W., Adams, J., Ellis, P. W., Houghton, R. A., Lomax, G., Miteva, D. A., …
Fargione, J. (2017). Natural climate solutions. Proceedings of the National Academy of
Sciences of the United States of America, 114(44), 11645–11650.
![Page 50: Effects of Restoration on Carbon Storage in Smelter ......2010/01/06 · part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or,](https://reader036.fdocuments.in/reader036/viewer/2022081613/5fb4c7298cdd7e784b7bc233/html5/thumbnails/50.jpg)
40
https://doi.org/10.1073/pnas.1710465114
Gunn, J., Keller, W., Negusanti, J., Potvin, R., Beckett, P., & Winterhalder, K. (1995).
Ecosystem recovery after emission reductions: Sudbury, Canada. Water, Air, & Soil
Pollution, 85(3), 1783–1788. https://doi.org/10.1007/BF00477238
Gunn, J. M., Conroy, N., Lautenbach, W. E., Pearson, D. A. B., Puro, M. J., Shorthouse, J. D., &
Wiseman, M. E. (1995). From Restoration to Sustainable Ecosystems. In John Gunn (Ed.),
Restoration and recovery of an industrial region. Springer series on environmental
management. (pp. 335–344). https://doi.org/10.1007/978-1-4612-2520-1_26
Gunn, J.M., Sein, R., Keller, B. W., & Beckett, P. (2001). Liming of acid and metal
contaminated catchments for the improvement of drainage water quality. Water, Air, and
Soil Pollution, 130, 1439–1444. https://doi.org/10.1023/A
Harmon, M. E., Woodall, C. W., Fasth, B., Sexton, J., & Yatkov, M. (2011). Differences between
standing and downed dead tree wood density reduction factors: A comparison across decay
classes and tree species. https://doi.org/10.2737/NRS-RP-15
Haynes, R. J., & Naidu, R. (1998). Influence of lime, fertilizer and manure applications on soil
organic matter. Nutrient Cycling in Agroecosystems, 51, 123–137.
https://doi.org/10.1023/A:1009738307837
Hazlett, P. W., Gordon, A. M., Sibley, P. K., & Buttle, J. M. (2005). Stand carbon stocks and soil
carbon and nitrogen storage for riparian and upland forests of boreal lakes in northeastern
Ontario. Forest Ecology and Management, 219(1), 56–68.
https://doi.org/10.1016/j.foreco.2005.08.044
Hutchinson, T. C., & Whitby, L. M. (1977). The effects of acid rainfall and heavy metal
particulates on a boreal forest ecosystem near the Sudbury smelting region of Canada.
Water, Air, and Soil Pollution, 7(4), 421–438.
Jackson, D. A. (1993). Stopping rules in principal components analysis : A comparison of
heuristical and statistical approaches. Ecology, 74(8), 2204–2214.
Jandl, R., Lindner, M., Vesterdal, L., Bauwens, B., Baritz, R., Hagedorn, F., … Byrne, K. A.
(2007). How strongly can forest management influence soil carbon sequestration?
Geoderma, 137(3–4), 253–268. https://doi.org/10.1016/j.geoderma.2006.09.003
Johnson, D. W. (1992). Effects of forest management on soil carbon storage. Water, Air, & Soil
Pollution, 1–2, 83–120.
Johnston, M. H., Homann, P. S., Engstrom, J. K., & Grigal, D. F. (1996). Changes in ecosystem
carbon storage over 40 years on an old-field/forest landscape in east-central Minnesota.
Forest Ecology and Management, 83(1–2), 17–26. https://doi.org/10.1016/0378-
1127(96)03704-8
Keith, H., Mackey, B. G., & Lindenmayer, D. B. (2009). Re-evaluation of forest biomass carbon
stocks and lessons from the world’s most carbon-dense forests. Proceedings of the National
Academy of Sciences, 106(28), 11635–11640. https://doi.org/10.1073/pnas.0901970106
Ketchledge, E. H., Leonard, R. E., Richards, N. A., Craul, P. F., & Eschner, A. R. (1985).
![Page 51: Effects of Restoration on Carbon Storage in Smelter ......2010/01/06 · part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or,](https://reader036.fdocuments.in/reader036/viewer/2022081613/5fb4c7298cdd7e784b7bc233/html5/thumbnails/51.jpg)
41
Rehabilitation of alpine vegetation in the Adirondack Mountains of New York State. Res.
Pap., 1–6. Retrieved from http://www.treesearch.fs.fed.us/pubs/21744
Kozlov, M. V., & Zvereva, E. L. (2015). Pollution in forests. In K. S.-H. Peh, R. . Corlette, & Y.
Bergeron (Eds.), Routledge Handbook of Forest Ecology (pp. 436–451).
https://doi.org/10.4324/9781315818290
Kozlov, M. V., & Zvereva, E. L. (2007). Industrial barrens: Extreme habitats created by non-
ferrous metallurgy. Life in Extreme Environments, 69–97. https://doi.org/10.1007/978-1-
4020-6285-8-5
Kurz, W. A., Shaw, C. H., Boisvenue, C., Stinson, G., Metsaranta, J., Leckie, D., … Neilson, E.
T. (2013). Carbon in Canada’s boreal forest — A synthesis. Environmental Reviews, 21(4),
260–292. Retrieved from http://www.nrcresearchpress.com/doi/abs/10.1139/er-2013-
0041#.VotbEPl97IU
Laiho, R., & Prescott, C. E. (2011). The contribution of coarse woody debris to carbon, nitrogen,
and phosphorus cycles in three Rocky Mountain coniferous forests. Canadian Journal of
Forest Research, 29(10), 1592–1603. https://doi.org/10.1139/x99-132
Lal, R. (2005). Forest soils and carbon sequestration. Forest Ecology and Management, 220(1–
3), 242–258. https://doi.org/10.1016/j.foreco.2005.08.015
Lambert, M.-C., Ung, C.-H., & Raulier, F. (2005). Canadian national tree aboveground biomass
equations. Canadian Journal of Forest Research, 35(8), 1996–2018.
https://doi.org/10.1139/x05-112
Lambert, R. L., Lang, G. E., & Reiners, W. A. (1980). Loss of mass and chemical change in
decaying boles of a subalpine balsam fir forest. Ecology, 61(6), 1460–1473.
Lewis, S. L., Wheeler, C. E., Mitchard, E. T., & Koch, A. (2019). Regenerate natural forests to
store carbon. Nature, 568(7750), 25–28.
Luyssaert, S., Schulze, E. D., Börner, A., Knohl, A., Hessenmöller, D., Law, B. E., … Grace, J.
(2008). Old-growth forests as global carbon sinks. Nature, 455(7210), 213–215.
https://doi.org/10.1038/nature07276
Martin, A. R., Doraisami, M., & Thomas, S. C. (2018). Global patterns in wood carbon
concentration across the world’s trees and forests. Nature Geoscience, 11(12), 915–920.
https://doi.org/10.1038/s41561-018-0246-x
McCall, J., Gunn, J., & Struik, H. (1995). Photo interpretive study of recovery of damaged lands
near the metal smelters of Sudbury, Canada. Water, Air, & Soil Pollution, 85(2), 847–852.
https://doi.org/10.1007/BF00476935
Meadows, M., & Watmough, S. A. (2012). An assessment of long-term risks of metals in
sudbury: A critical loads approach. Water, Air, and Soil Pollution, 223(7), 4343–4354.
https://doi.org/10.1007/s11270-012-1199-0
Mensah, S., Veldtman, R., Assogbadjo, A. E., Glèlè Kakaï, R., & Seifert, T. (2016). Tree species
diversity promotes aboveground carbon storage through functional diversity and functional
dominance. Ecology and Evolution, 6(20), 7546–7557. https://doi.org/10.1002/ece3.2525
![Page 52: Effects of Restoration on Carbon Storage in Smelter ......2010/01/06 · part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or,](https://reader036.fdocuments.in/reader036/viewer/2022081613/5fb4c7298cdd7e784b7bc233/html5/thumbnails/52.jpg)
42
Moeslund, J. E., Arge, L., Bøcher, P. K., Dalgaard, T., & Svenning, J. C. (2013). Topography as
a driver of local terrestrial vascular plant diversity patterns. Nordic Journal of Botany,
31(2), 129–144. https://doi.org/10.1111/j.1756-1051.2013.00082.x
Moore, J. D., & Ouimet, R. (2006). Ten-year effect of dolomitic lime on the nutrition, crown
vigor, and growth of sugar maple. Canadian Journal of Forest Research, 36(7), 1834–1841.
https://doi.org/10.1139/X06-081
Moore, J. N., & Luoma, S. N. (1990). Hazardous wastes from large-scale metal extraction: A
case study. Environmental Science and Technology, 24(9), 1278–1285.
https://doi.org/10.1021/es00079a001
Nave, L. E., Swanston, C. W., Mishra, U., & Nadelhoffer, K. J. (2013). Afforestation effects on
soil carbon storage in the United States: A synthesis. Soil Science Society of America
Journal, 77(3), 1035–1047. https://doi.org/10.2136/sssaj2012.0236
Nelson, D. W., & Sommers, L. E. (1996). Total Carbon, Organic Carbon, and Organic Matter. In
Methods of Soil Analysis: Part 3 Chemical Methods. Soil Science Society of America (pp.
961–1010).
Ontario Ministry of the Environment Conservation and Parks. (2011). Soil, ground water and
sediment standards for use under Part XV.1 of the Environmental Protection Act. Retrieved
June 12, 2019, from https://www.ontario.ca/page/soil-ground-water-and-sediment-
standards-use-under-part-xv1-environmental-protection-act
Pan, Y., Birdsey, R. A., Fang, J., Houghton, R., Kauppi, P. E., Kurz, W. A., … Ciais, P. (2011).
A large and persistent carbon sink in the world’s forests. Science, 338(6045), 988–993.
Paradelo, R., Virto, I., & Chenu, C. (2015). Net effect of liming on soil organic carbon stocks: A
review. Agriculture, Ecosystems and Environment, 202, 98–107.
https://doi.org/10.1016/j.agee.2015.01.005
Périé, C., & Ouimet, R. (2011). Organic carbon, organic matter and bulk density relationships in
boreal forest soils. Canadian Journal of Soil Science, 88(3), 315–325.
https://doi.org/10.4141/cjss06008
Pugh, T. A. M., Lindeskog, M., Smith, B., Poulter, B., Arneth, A., Haverd, V., & Calle, L.
(2019). Role of forest regrowth in global carbon sink dynamics. Proceedings of the
National Academy of Sciences of the United States of America.
https://doi.org/10.1073/pnas.1810512116
Russell, M. B., Fraver, S., Aakala, T., Gove, J. H., Woodall, C. W., D’Amato, A. W., & Ducey,
M. J. (2015). Quantifying carbon stores and decomposition in dead wood: A review. Forest
Ecology and Management, 350, 107–128. https://doi.org/10.1016/j.foreco.2015.04.033
SARA Group. (2009). Sudbury soils study. Summary of Volume III: Ecological risk assessment.
Sherman, G., & Beckett, P. (2003). Carbon sequestration patterns in the replanted areas of the
Sudbury barrens. Proceedings Sudbury Mining and the Environment International
Conference, 1–8. Retrieved from
http://pdf.library.laurentian.ca/medb/conf/Sudbury03/SmelterLandscape/139.pdf
![Page 53: Effects of Restoration on Carbon Storage in Smelter ......2010/01/06 · part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or,](https://reader036.fdocuments.in/reader036/viewer/2022081613/5fb4c7298cdd7e784b7bc233/html5/thumbnails/53.jpg)
43
Sherman, Geoffrey. (2005). Carbon sequestration in the developing terrestrial ecosystem on the
remediated Sudbury barrens. Laurentian University.
Smith, J. E., Heath, L. S., & Jenkins, J. C. (2003). Forest volume-to-biomass models and
estimates of mass for live and standing dead trees of US forests. United States Department
of Agriculture.
Smithwick, E. A. H., Remillard, S. M., Harmon, M. E., Franklin, J. F., & Acker, S. A. (2002).
Potential upper bounds of carbon stores in forests of the Pacific Northwest. Ecological
Applications, 12(5), 1303–1317. https://doi.org/10.1890/1051-
0761(2002)012[1303:pubocs]2.0.co;2
Szkokan-Emilson, E. J., Wesolek, B. E., & Gunn, J. M. (2011). Terrestrial organic matter as
subsidies that aid in the recovery of macroinvertebrates in industrially damaged lakes.
Ecological Applications, 21(6), 2082–2093. https://doi.org/10.1890/10-1967.1
Ung, C.-H., Bernier, P., & Guo, X.-J. (2008). Canadian national biomass equations: new
parameter estimates that include British Columbia data. Canadian Journal of Forest
Research, 38(5), 1123–1132. https://doi.org/10.1139/x07-224
Van Wagner, C. E. (1968). The line transect method of fuel sampling. Forest Science, 14(1), 0–
3.
Vanttinen, S. L. (1993). Daisy Lake Watershed Rehabilitation Report #2.
Vesterdal, L., Clarke, N., Sigurdsson, B. D., & Gundersen, P. (2013). Do tree species influence
soil carbon stocks in temperate and boreal forests? Forest Ecology and Management, 309,
4–18. https://doi.org/10.1016/j.foreco.2013.01.017
Vogel, J. G., & Gower, S. T. (1998). Carbon and nitrogen dynamics of boreal jack pine stands
with and without a green alder understory. Ecosystems, 1(4), 386–400.
https://doi.org/10.1007/s100219900032
Walker, X. J., Baltzer, J. L., Cumming, S. G., Day, N. J., Ebert, C., Goetz, S., … Mack, M. C.
(2019). Increasing wildfires threaten historic carbon sink of boreal forest soils. Nature,
572(7770), 520–523. https://doi.org/10.1038/s41586-019-1474-y
Winterhalder, K. (1983). The use of manual surface seeding, liming & fertilization in the
reclamation of acid metal-contaminated land in the sudbury, ontario mining and smelting
region of canada. Environmental Technology Letters, 4(5), 209–216.
https://doi.org/10.1080/09593338309384197
Winterhalder, K. (1995). Early history of human activities in the Sudbury area and ecological
damage to the landscape. In John Maxwell Gunn (Ed.), Restoration and recovery of an
industrial region (pp. 17–31). Springer, New York.
Winterhalder, K. (1996). Environmental degradation and rehabilitation of the landscape around
Sudbury, a major mining and smelting area. Environmental Reviews, 4(3), 185–224.
https://doi.org/10.1139/a96-011
Wisconson Department of Natural Resources. (2016). Jack Pine. In Silvicultural Handbook (pp.
1–73).
![Page 54: Effects of Restoration on Carbon Storage in Smelter ......2010/01/06 · part, for scholarly purposes may be granted by the professor or professors who supervised my thesis work or,](https://reader036.fdocuments.in/reader036/viewer/2022081613/5fb4c7298cdd7e784b7bc233/html5/thumbnails/54.jpg)
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APPENDIX
SUPPLEMENTARY TABLES AND FIGURES
Table A1 CBM-CFS3 species-specific DBH-biomass equations from Lambert et al. (2005) were
used for balsam poplar, eastern hemlock, eastern white pine, large-tooth aspen, jack pine, red
maple, red oak, and red pine.
Species Parameter Estimate SE
Balsam poplar (Populus balsamifera)
βwood1 0.0510 0.0033
βwood2 2.4529 0.0205
βbark1 0.0297 0.0035
βbark2 2.1131 0.0375
βbranches1 0.0120 0.0014
βbranches2 2.4165 0.0376
βfoliage1 0.0276 0.0018
βfoliage2 1.6215 0.0240
Eastern hemlock (Tsuga canadensis)
βwood1 0.0619 0.0030
βwood2 2.3821 0.0150
βbark1 0.0139 0.0010
βbark2 2.3282 0.0210
βbranches1 0.0217 0.0031
βbranches2 2.2653 0.0420
βfoliage1 0.0776 0.0069
βfoliage2 1.6995 0.0292
Eastern white pine (Pinus strobus)
βwood1 0.0997 0.0129
βwood2 2.2709 0.0350
βbark1 0.0192 0.0016
βbark2 2.2038 0.0237
βbranches1 0.0056 0.0008
βbranches2 2.6011 0.0381
βfoliage1 0.0284 0.0024
βfoliage2 1.9375 0.0248
Large-tooth aspen (Populus grandidentata)
βwood1 0.0959 0.0144
βwood2 2.3430 0.0483
βbark1 0.0308 0.0035
βbark2 2.2240 0.0388
βbranches1 0.0047 0.0006
βbranches2 2.6530 0.0435
βfoliage1 0.0080 0.0016
βfoliage2 2.0149 0.0629
Jack pine (Pinus banksiana)
βwood1 0.0804 0.0042
βwood2 2.4041 0.0168
βbark1 0.0184 0.0009
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βbark2 2.0703 0.0165
βbranches1 0.0079 0.0011
βbranches2 2.4155 0.0486
βfoliage1 0.0389 0.0029
βfoliage2 1.7290 0.0251
Red maple (Acer rubrum)
βwood1 0.1014 0.0052
βwood2 2.3448 0.0173
βbark1 0.0291 0.0027
βbark2 2.0893 0.0320
βbranches1 0.0175 0.0034
βbranches2 2.4846 0.0603
βfoliage1 0.0515 0.0065
βfoliage2 1.5198 0.0400
Red oak (Quercus rubra)
βwood1 0.1754 0.0149
βwood2 2.1616 0.0267
βbark1 0.0381 0.0051
βbark2 2.0991 0.0403
βbranches1 0.0085 0.0028
βbranches2 2.7790 0.0979
βfoliage1 0.0373 0.0029
βfoliage2 1.6740 0.0268
Red pine (Pinus resinosa)
βwood1 0.0564 0.0034
βwood2 2.4465 0.0192
βbark1 0.0188 0.0006
βbark2 2.0527 0.0102
βbranches1 0.0033 0.0005
βbranches2 2.7515 0.0455
βfoliage1 0.0212 0.0014
βfoliage2 2.0690 0.0204
Table A2 CBM-CFS3 species-specific DBH-biomass equations updated for CBM-CFS3 in Ung
et al. (2008). These equations were used for trembling aspen, unknown deciduous (too decayed
to ID), white birch, and white spruce. Willow and cherry trees were not identified to species, so
“All hardwoods” tree equations were used (Ung et al., 2008).
Species Parameter Estimate SE
Trembling aspen (Populus tremuloides)
βwood1 0.0608 0.0029
βwood2 2.4735 0.0153
βbark1 0.0159 0.0006
βbark2 2.4123 0.0131
βbranches1 0.0082 0.0008
βbranches2 2.5139 0.0327
βfoliage1 0.0235 0.0032
βfoliage2 1.6656 0.0440
Unknown deciduous βwood1 0.0864 0.0015
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βwood2 2.3715 0.0053
βbark1 0.0226 0.0008
βbark2 2.2151 0.0112
βbranches1 0.0186 0.0007
βbranches2 2.4462 0.0127
βfoliage1 0.0385 0.0010
βfoliage2 1.6255 0.0089
White birch (Betula papyrifera)
βwood1 0.0604 0.0016
βwood2 2.4959 0.0090
βbark1 0.0140 0.0008
βbark2 2.3923 0.0195
βbranches1 0.0147 0.0009
βbranches2 2.5227 0.0217
βfoliage1 0.0591 0.0026
βfoliage2 1.6036 0.0167
White spruce (Picea glauca)
βwood1 0.0334 0.0008
βwood2 2.5980 0.0086
βbark1 0.0114 0.0004
βbark2 2.3057 0.0115
βbranches1 0.0302 0.0019
βbranches2 2.0927 0.0227
βfoliage1 0.1515 0.0079
βfoliage2 1.5012 0.0182
Table A3 Method accuracy for comparing CRMs to my total metals data. NAs for analytical
computation indicate impossible comparisons because concentrations are <DL, NAs for method
accuracy represent missing data. Method accuracy is for total metals only.
Method Accuracy Analytical Precision
TILL- 1 CRM
% recovery compared
to certified values
Total metals: Relative
percent difference
Bioavailable
metals: Relative
percent difference
As 287.59% 3.19% 59.82%
Cd NA 0.99% 22.40%
Co 90.56% 0.62% 0.14%
Cu 309.57% 0.41% 0.58%
Ni 95.83% 0.14% 0.91%
Pb 90.38% 0.53% NA
Se NA 8.03% NA
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Figure A1 Map of wetness index in upland industrial barren plots, calculated using tasseled cap.
Z-scores were used for final data use. More positive wetness index values indicate wetter soil,
more negative values indicate drier soil.
Figure A2 Broken-stick analysis showing how many PCs to include in linear model. PCs where
observed eigenvalues exceed broken-stick model eigenvalues were included. In this case just
PC1 met this criterion and was included.
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Table A4 Pearson correlation coefficient (r) matrix for predictors and total C storage included in
linear regression. A limit of ≤ 0.75 between any two predictors was used for any two variables
being included in the linear model. No predictors reached this correlation limit.
C
storage
Wetness
index
Plant
richness
PC1
of
COC
pH Distance
from
smelter
Elevation Jack pine
frequency
C storage 1.00 0.74 0.42 -0.24 -0.08 0.076 0.022 0.51
Wetness
index
0.74 1.00 0.37 -0.08 -0.07 -0.11 -0.08 0.58
Plant
richness
0.42 0.37 1.00 0.39 0.63 -0.12 0.12 0.63
PC1 Of
COC
-0.24 -0.08 0.39 1.00 0.61 -0.27 0.07 -0.11
pH -0.08 -0.07 0.63 0.61 1.00 -0.11 -0.03 -0.08
Distance
from
smelter
0.076 -0.11 -0.12 -0.12 -0.11 1.00 0.34 0.03
Elevation 0.022 -0.08 0.12 0.07 -0.03 0.34 1.00 0.29
Jack pine
frequency
0.51 0.58 0.09 -0.11 0.29 0.03 0.29 1.00
Table A5 Pearson correlation p-values matrix for predictors and total C storage included in
linear regression.
C
storage
Wetness
index
Plant
richness
PC1
of
COC
pH Distance
from
smelter
Elevation Jack pine
frequency
C storage NA <0.0001 <0.05 0.19 0.67 0.68 0.90 <0.01
Wetness
index
<0.0001 NA <0.05 0.67 0.70 0.56 0.67 <0.001
Plant
richness
<0.05 <0.05 NA <0.05 <0.0001 0.53 0.52 0.61
PC1 Of
COC
0.19 0.67 <0.05 NA <0.001 0.14 0.70 0.55
pH 0.67 0.70 <0.0001 <0.001 NA 0.53 0.89 0.67
Distance
from
smelter
0.68 0.56 0.53 0.14 0.53 NA 0.05 0.87
Elevation 0.90 0.67 0.52 0.70 0.89 0.05 NA 0.11
Jack pine
frequency
<0.01 <0.001 0.61 0.55 0.67 0.87 0.11 NA
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Table A6 Principal component loadings for COC (chemicals of concern) bioavailable
concentrations for PC1 (principal component 1) included as a predictor in the linear regression
for total C storage. Loadings represent the PC coefficients, which are the correlations between
each COC and PC1, therefore representing the contribution of each COC to PC1 and
subsequently the linear model.
Element Loading
As -0.238
Cd 0.466
Co -0.503
Cu -0.388
Ni -0.532
Pb 0.200
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Figure A3 Total concentrations of Sudbury chemicals of concern (COC) found across untreated
plots (U), limed, fertilized, and seeded plots (L), tree-planted plots (T), and limed, fertilized, and
seeded + tree-planted plots (L+T) in upland industrial barrens (n = 32). Element concentrations
that were below detection limit were computed as half of detection limit. Dashed lines indicate
MECP standards for unpolluted soils (Ontario Ministry of the Environment Conservation and
Parks, 2011). Different letter designations above plots indicate significant differences at p < 0.05.
Only [Se] was significantly different among treatments.
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Figure A4 Bioavailable concentrations of Sudbury chemicals of concern (COC) found across
untreated plots (U), limed, fertilized, and seeded plots (L), tree-planted plots (T), and limed,
fertilized, and seeded + tree-planted plots (L+T) in upland industrial barrens (n = 32). Element
concentrations that were below detection limit were computed as half of detection limit. All Se
concentrations were below the detection limit so it was not plotted. Different letter designations
above plots indicate significant differences at p < 0.05.
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Table A7 Treatments and C storage for all study sites in untreated (U), limed, fertilized, and
seeded (L), tree-planted (T), and limed, fertilized, and seeded + tree-planted (L+T) treatments.
Elevation indicates whether sites were high (upland industrial barrens) or low (lowland valleys).
All C units are in Mg C ha-1.
Site Elevation
class
Treatment FWD
C
CWD
C
Shrub
C
Herb
C
Tree
C
Mineral
soil C
Organic
soil C
Σ C
storage
HP1N Low U 1.2 1.6 6.4 0.7 31.3 36.5 13.1 90.6
HP2N Low U 1.4 0.9 9.6 1.1 33.0 30.3 11.4 87.7
HP3N Low U 1.3 1.3 0.3 0.5 49.5 25.5 11.7 90.2
HP4N Low U 1.2 1.1 10.5 0.4 33.1 24.9 9.9 81.1
HP5N Low U 0.8 1.5 3.7 1.5 34.0 18.8 29.1 89.4
IP1MF High U 0.1 0.0 1.0 4.5 0.1 19.5 8.2 33.6
IP1N High L+T 0.1 0.2 0.8 2.3 26.0 46.6 11.2 87.3
IP2MF High U 0.3 0.0 0.7 1.5 0.2 17.2 3.2 23.0
IP2N High U 0.1 0.1 0.0 0.1 0.2 9.8 6.1 16.3
IP3M High U 0.3 0.1 0.0 4.1 2.1 46.9 10.9 64.3
IP3N Low U 0.4 0.4 2.7 0.8 10.5 29.3 15.2 59.3
IP4MF High U 0.2 0.1 2.0 3.1 0.0 32.1 5.6 43.2
IP4N Low U 0.7 1.2 2.7 0.6 36.0 23.1 12.1 76.4
IP5N Low U 0.9 0.2 2.3 1.6 15.5 38.3 10.0 68.8
IP6B Low U 1.2 0.1 0.0 2.1 6.5 31.2 10.7 51.6
IP6N High L+T 0.2 0.1 5.4 0.3 22.1 33.0 12.2 73.2
IP8R Low U 0.0 0.0 0.0 1.4 0.2 31.9 3.7 37.3
JP10R High L+T 0.5 0.0 3.8 1.1 15.4 22.0 6.5 49.3
JP11R High L 0.3 0.0 0.0 1.8 0.9 13.2 4.2 20.4
JP1MF High L+T 0.4 0.0 0.3 1.8 13.2 20.5 6.0 42.2
JP1N Low L 0.7 0.0 4.8 2.5 31.0 47.5 11.6 98.1
JP2M Low L 2.7 1.0 2.2 1.0 39.1 36.2 11.2 93.5
JP2N High L+T 0.2 0.0 0.1 3.4 18.1 33.6 4.3 59.7
JP2R High L 0.1 0.0 0.0 1.5 1.4 9.8 3.1 15.9
JP3MF High L+T 0.2 0.0 0.0 0.1 20.5 32.9 6.8 60.6
JP3N High L+T 0.1 0.2 2.6 3.5 28.4 34.8 13.5 83.2
JP4N High L+T 0.1 0.1 4.0 1.1 20.8 11.4 8.4 46.0
JP4R High L 0.0 0.0 0.0 0.7 0.9 16.6 4.0 22.2
JP5B High L 0.2 0.0 0.0 3.1 0.5 22.9 8.8 35.5
JP5N High L+T 0.5 0.1 0.9 0.7 16.6 19.2 7.9 45.9
JP5R High L 0.0 0.0 0.0 0.3 0.1 9.2 4.9 14.5
JP6M Low L 1.7 0.2 16.4 1.0 37.5 37.4 17.6 111.7
JP6N High L+T 0.6 0.0 2.5 0.9 20.0 17.8 11.2 53.1
JP7M High L 0.5 0.0 6.1 4.3 13.3 39.4 7.8 71.5
JP8B High L+T 0.5 0.1 0.0 0.6 10.9 27.4 7.3 46.7
JP9B High L+T 0.2 0.1 0.6 4.4 19.6 21.2 5.6 51.7
JP9M High L 0.1 0.0 0.6 5.7 2.2 43.2 7.6 59.4
OP1N High T 0.5 0.0 2.9 3.2 17.0 29.5 6.6 59.7
OP2N High T 0.1 0.0 0.0 1.9 12.9 24.7 8.3 47.9
OP3N High T 0.4 0.2 0.0 1.5 13.7 14.8 4.4 34.9
OP4N High T 0.1 0.0 0.0 0.6 9.1 19.0 3.6 32.5
OP5N High T 0.5 0.0 11.0 2.7 14.8 25.6 6.4 61.0
OP6N High T 0.6 0.2 0.0 0.6 11.9 26.8 2.7 42.8
OP7N High T 0.4 0.0 0.0 1.9 12.8 19.0 6.3 40.4
OP8N High T 0.5 0.1 3.8 2.1 12.0 35.2 7.7 61.6
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Table A8 Summary of site characteristics for all study sites. Elevation is in meters above sea
level. Plant species richness is the total number of unique plant species (including trees, shrubs,
and herbs) identified per site. Smelter distance is the distance (m) from the historic Coniston Cu
and Ni smelter. Wetness index is the tasseled cap measurements of relative wetness among sites.
Soil pH is the mean pH of the 0-5 cm mineral soil layer. Jack pine count is the number of jack
pine per plot.
Site Latitude Longitude Elevation (MASL)
Plant species richness
Smelter distance
(m)
Wetness index
Soil pH
Jack pine
count HP1N 46.45446 -80.89144 257.9 21 4757 294.32 3.99 0
HP2N 46.45451 -80.89005 257.2 18 4661 1406.06 4.39 0
HP3N 46.45404 -80.88886 249.2 15 4640 1032.93 4.48 0
HP4N 46.45366 -80.88771 243.5 17 4583 -445.95 4.51 0
HP5N 46.45305 -80.88608 237.5 19 4540 -756.82 4.50 1
IP1MF 46.45874 -80.88594 303.8 11 4139 -5158.90 4.30 0
IP1N 46.46082 -80.88336 302.8 18 3841 -622.41 4.70 98
IP2MF 46.45957 -80.88473 305.5 13 4017 -5299.23 4.48 0
IP2N 46.45805 -80.88740 299.5 7 4280 -3764.56 4.10 0
IP3M 46.45815 -80.88466 280.5 7 4102 -1978.91 4.20 0
IP3N 46.45819 -80.88218 273.9 12 3947 -1220.14 4.22 0
IP4MF 46.46007 -80.88357 303.8 9 3900 -5144.05 4.37 0
IP4N 46.45691 -80.88188 256.8 23 4005 862.05 4.55 0
IP5N 46.46062 -80.88365 255.8 18 4325 -1059.49 4.15 1
IP6B 46.45665 -80.88474 273.6 13 4207 -2736.49 4.28 0
IP6N 46.46110 -80.88406 301.4 26 3867 -668.01 5.16 59
IP8R 46.45564 -80.88381 265.8 5 4220 -4306.37 3.70 0
JP10R 46.46192 -80.88290 303.8 19 3759 -2372.66 5.50 57
JP11R 46.46482 -80.87677 293.2 11 3180 -3873.57 4.72 1
JP1MF 46.45956 -80.88070 292.8 17 3752 -2758.58 5.30 61
JP1N 46.46313 -80.87595 278.2 23 3231 958.03 5.40 1
JP2M 46.45877 -80.87906 267.0 18 3715 -241.20 4.51 0
JP2N 46.46173 -80.88268 302.5 16 3740 -1701.99 5.12 74
JP2R 46.46140 -80.87875 292.5 13 3517 -3759.80 5.14 2
JP3MF 46.46076 -80.88135 301.9 13 3721 -2642.55 5.19 111
JP3N 46.46304 -80.88094 299.3 17 3567 -599.21 4.46 115
JP4N 46.46216 -80.88191 302.4 20 3679 -1310.16 4.87 73
JP4R 46.45996 -80.87919 287.6 20 3636 -5362.56 6.55 1
JP5B 46.46468 -80.87294 292.4 17 2943 -4556.48 4.51 0
JP5N 46.46132 -80.88208 302.8 17 3732 -1313.98 4.39 74
JP5R 46.46198 -80.87549 297.0 9 3274 -3094.33 4.96 0
JP6M 46.46129 -80.87642 278.5 26 3368 1027.13 5.11 0
JP6N 46.46139 -80.87992 296.2 25 3720 -985.40 5.61 56
JP7M 46.46271 -80.87844 288.6 27 3462 -925.02 4.88 0
JP8B 46.46032 -80.87942 292.0 15 3626 -2695.21 4.98 28
JP9B 46.46148 -80.88137 300.1 18 3674 -440.92 5.02 62
JP9M 46.46323 -80.87833 289.4 13 3371 -541.17 4.62 0
OP1N 46.46501 -80.88276 291.0 12 3573 -1621.47 4.26 70
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OP2N 46.46396 -80.88177 296.7 9 3560 -2130.04 4.14 41
OP3N 46.46303 -80.88197 301.3 8 3631 -2533.72 4.29 117
OP4N 46.46454 -80.88415 294.4 10 3696 -3099.28 4.43 79
OP5N 46.46355 -80.88184 299.9 13 3602 -1430.90 4.42 89
OP6N 46.46563 -80.88241 284.5 10 3523 -1512.93 4.45 72
OP7N 46.46501 -80.88328 292.5 11 3613 -1236.79 4.36 87
OP8N 46.46456 -80.88263 290.4 11 3595 -2038.81 4.19 71