UEA MSC DISSERTATION
Identifying and quantifying long-term
agricultural carbon storage in the UK
A case study on the Waitrose Farm at Leckford
Estate
Bryony Ecclestone MSc, Environmental Management and Assessment (2011-2012)
Table of Contents
Table of Contents .................................................. 2
Dedication .......................................................... 4
Glossary ............................................................ 5
UNFCCC- United Nations Framework Convention on Climate
Change. A treaty with the aim of stabilizing greenhouse gas
emissions. .......................................................... 5
Abstract ............................................................. 5
Issue ...................................................................
Case study ............................................................
Results ................................................................
Analysis ...............................................................
6
6
6
7
Identifying and quantifying long -term agricultural carbon
storage in the UK .................................................. 9
1. Introduction ..................................................... 9
1.1 Statement of problem ............................................ 9
1.2 Intr oduction to climate change ............................... 10
1.2.1 Greenhouse gases ................................................ 11
1.2.2 What is being done .............................................. 12
1.3 The need for im pr oved car bon storage ....................... 14
1.4 CASE STUDY: Background to Leckford Estate. ............. 17
1.5 Idea of pr oject an d purpose of study ......................... 19
1.6 Significance of the study to the field ........................ 20
2. Aims and Obj ectives .......................................... 21
2.1 Aims .............................................................. 21
2.2 Objectives ....................................................... 21
3. Literature Review ............................................. 22
3.1 The growing problem of Climate Change ....................
3.2 Agricultural Carbon Storage an d sequestrations (CCS) ....
3.3 Carbon Sequestration in Trees ................................
3.3.1 Methods for measuring carbon sequestration in trees, ...
3.4 Soil Carbon Storage ............................................
3.4.1 Methods for measuring soil carbon ...........................
22
25
27
31
35
43
4. Methods ......................................................... 45
4.1 Initial investigation of site. ..................................
4.2 Woodland Sampling Materials and Methods .................
4.2.1 Study area .........................................................
4.2.2 Sampling design and data collection .........................
4.2.3 Woodland Biomass Calculation ...............................
4.2.4 Measurement validity + reliability ...........................
45
46
46
46
47
49
2
4.2.5 Data collection ...................................................
4.2.6 Data analysis ......................................................
4.3 Soil Sampling Materials and Methods ........................
4.3.1 Study area .........................................................
4.3.2 Sampling Design and Data collection ........................
4.3.3 Sampling methods ................................................
4.3.4 Data collection and procedures ...............................
4.3.5 Data Analysis .....................................................
49
49
50
50
51
52
52
53
5. Results .......................................................... 54
5.1 Woodland Results ............................................... 54
5.2 Soil Results ..................................................... 58
6. Discussion ...................................................... 62
6.1 Analysis of results .............................................. 62
6.1.1 Woodlands ......................................................... 62
6.2 Soils .............................................................. 65
6.3 Analysis of investigation methods ............................ 71
6.4 Limitations ...................................................... 72
6.5 Recommen dations for future research an d ongoing pr ojects
........................................................................ 73
7. Conclusion ..................................................... 74
8. References ...................................................... 74
9. Appendix ....................................................... 80
Appendix
Appendix
Appendix
Appendix
Appendix
Appendix
Appendix
Appendix
1 ...........................................................
2 ...........................................................
3 ...........................................................
4 ...........................................................
5 ...........................................................
6 ...........................................................
7 ...........................................................
8. ..........................................................
80
81
81
82
83
84
86
87
3
Dedication
I could not have completed this project with out the help and
guidance of so many people, a few of whom I would like to thank
here.
Firstly, Jane Powell has always had time to answer my questions
on all topics, responded to my emails with more information than I
could have hoped for and generally left me at the end of our
meetings with a smile.
Secondly, Jim Robinson and all those at Leckford Estate who took
time out of their schedules to guide me around, help me with my
investigations and show me what a beautiful site it really is.
My family and the Chapmans have given me so much of their time,
thoughts, help and always cheered me up.
Finally, my biggest thanks go to Daniel. For bringing me tea when
I could no longer think straight and giving up a whole week of his
time to sample trees, get chased by bees and stung by nettles. Then
reading through the work again to check what parts I had
forgotten.
Thank you.
4
Glossary
Biosequestration (of carbon). Biological storage of carbon in natural
materials such as trees, soil, rocks or bodies of water.
CC- Climate Change. The effect of increasing greenhouse gases i s
causing changes in the global climate.
CFCs. Chlorofluorocarbons. Organic compounds which contribute to
the greenhouse effect.
C storage- Carbon Storage. Storage of carbon, either naturally or by
made-made operations.
GHG- Greenhouse Gas. Any gas, natural or synthetic, which
contributes to the insulative effect of the atmosphere. Includes carbon
dioxide, methane and water vapor.
Greenhouse Effect- The effect of increasing greenhouse gases present
in the atmosphere, changing climates and temperatures worldwide.
FAO- Food and Agriculture organization of the United Nations. Global
body in place to promote sustainable methods for food production.
FC- Forestry Commission. A UK government body dedicated to
protection of forests and their expansion.
HLS scheme - Higher Level Stewardship scheme . supported by Natural
England aimed at delivering ecological and biological benefits to areas
deemed significant.
KP- Kyoto Protocol. A Protocol to the UNFCCC dedicated to fighting
climate change.
Sequestration (of carbon)- Storage of carbon by a number of means .
SOM- Soil organic Matter. Organic matter contained within soils.
SOC,- Soil organic carbon. Carbon contained within soil organic
matter.
IPCC- Intergovernmental on Climate Change. Set up at the request of
member bodies, a panel dedicated to examining the scientific evidence
for climate change and conveying the perceived risk to all bodies
UNFCCC- United Nations Framework Convention on Climate Change.
A treaty with the aim of stabilizing greenhouse gas emissions.
Abstract
5
Issue
Due to the rising pressure of climate c hange awareness and public
opinion,
this
investigation
examines
the
potential
capacity
for
woodland and soil in the United Kingdom to store excess carbon
dioxode and methods by which this could be quantified. Carbon
storage has been identified in holding a key role in reducing net
carbon
emissions,
following
recent
rapid
increases
in
anthropogenic outputs. Leckford Estate was used as a case study
for identifying long-term biological carbon sinks and models that
allow easy quantification of the carbon stored within each area.
Case study
After
visiting
the
site,
these
long-term
carbon
stores
were
identified as areas of designated woodland and the varied types of
soil. These were examined and analysed to understand the current
volumes of carbon being stored, then modeled to produce figures
for potential future storage of carbon, given different management
practices and methods.
The investigation examines the most suitable method to efficiently
calculate carbon storage by biosequestration, in order to produce
total figures given constraints on time and data that farmers have.
Management plans for the site were suggested from these results,
allowing transferability and implementation of the conclusions.
Results
Calculations showed that there was a wide variation in the amount
of carbon being stored on the site, with differences predominantly
due
to
land
use.
Differences
between
conditions
and
species
examined in woodland across the site is wide, and an individual
calculation of the C-storage of each site provided a more accurate
picture than general farm carbon calculators. Another factor that
6
examined was the highly varied condition of the soil, and therefore
the
organic
content
contained
differences in carbon storage
low levels of
within.
This
showed
great
as agricultural soils demonstrated
soil organic carbon
present, whilst wetland soils
contained levels around three times higher .
The current carbon storage in the woodland areas (area 81.4 ha)
was
calculated
at
224
tonnes
of
carbon
(tC)
added
in
2012,
10,735tC in total with the potential to reach 11,742.54tC in 10
years
following
best
practices,
and
11,474.01
tonnes
following
current practices without additional management, a difference of
nearly 270 tonnes.
Current soil carbon storage was estimated only for the woodland,
arable, orchard and specific peaty areas identi fied. The current
arable
storage
is
155tCha-1
in
topsoils
and
107tCha-1
in
the
subsoils. This is in comparison to the higher levels of 293tCha -1
and 275tCha-1 for conifererous woodlands. The potential arable
subsoils could reach a level of 127tCha -1 in 10 years and 157tCha1 in 50 years with improved practices, but this comes at decreasing
rates over time and would need active management in comp arison
to
the
woodlands,
which
could
store
increased
carbon
without
further management or inputs.
Analysis
This is a quickly developing field but it is highly complex due to
the nature of woodlands and soil carbon composition and there is
much conflict between the research progressing this field as to
which
is
a
more
valuable
store.
Some
researchers
are
of
the
opinion that biosequestration remains a valid option to continue to
combat climate change (Grace, 2004; Milne 2000). Others (Hester
and Harrison, 2010; Lehmann et al, 2006) believe that although
there is the potential for improved storage, actual rates that could
occur in the UK are minimal and other avenues must be explored to
assist with the reduction of GHG emissions . There are also other
areas of sequestration study to develop, such as Biochar, in order
7
to achieve the rapid carbon sequestration needed to combat the
climatic changes resulting from GHG emissions.
This study believes that, due to the degraded nature of some of the
woodlands and arable soils investigated, there is great potential
locally and globally to increase terrestrial carbon sinks , provided
careful management plans and advice are provided . Soil carbon
levels can be increased by around 2.1Tha-1 (tonnes per hectare)
each year with minimal disruption to farming practices. Higher
values of 12Tha-1 each year are possible but this is to the detriment
of current agricultural production, which is key to the UK due to
the
dense
conflict
population
between
and
reducing
land
carbon
constrictions.
emissions
This
by
results
producing
in
local
food, versus increasing local soil carbon and importing food. The
woodlands on the site again showed potential for increased carbon
storage,
given
preserve
the
limited
appropriate
onsite
options
management
biodiversity
available
for
and
some
and
investment,
aesthetic
areas,
values
such
as
but
there
the
to
are
highly
maintained Parkland and Water Garden sites.
8
Identifying and quantify ing long -term
agricultural carbon storage in the UK
1. Introduction
1.1 Statement of problem
Climate change, sometimes falsely named ‘Global Warming’, is the
theory commonly understood to be driving the rapid alteration
observed
in
global climate patterns.
Whilst warming associated
with the greenhouse effect is expected to take place in many areas,
there
are
other
predicted
to
where
cause
the
climatic
localised
cooling,
changes
are
uncertain
hence
the
term
but
‘Climate
Change’. Average global temperatures increased at nearly twice the
rate in the last 50 years, compared to that over the last 100. The
20th century saw global temperatures increase by around 0.7 4C,
with
land
temperatures
increasing
more
rapidly
than
ocean
temperatures (UN, 2012). These changes led the IPCC to conclude
with 90% certainty, that these changes were the result of climate
change. (IPCC, 2007)
In the last 50 years recorded atmospheric CO2 (carbon dioxide)
levels
have
volume
been
released,
rapidly
mostly
increasing.
from
This
is
both
anthropogenic
in
terms
sources,
of
and
concentrations in the atmosphere. Current levels were recorded as
395ppm (parts per million) at the Mauna Loa observatory in June
2012
(ERSL, 2012) increased from 278 ppm before the industrial
movement of 1750 (UN, 2012).
Many correlative increases in global temperature and instances of
extreme weather conditions have used to confirm these climatic
changes as well as smaller climatic changes, which affect many
ecosystems. For example, summer 2012 in the UK has so far the
wettest on record with biodiversity impacts such as
Brownsea
Island
being
flooded
in
their
nests
Puffins on
and
having
devastating effects on populations (BBC, 2012).
9
1.2 Introduction to climate change
Climate
change
is
a
hotly
debated
process
currently
severely
affecting our environment and recognised as ‘one of the biggest
threats faced by today’s society’ (OECD 2002). Whilst there is still
much debate over its effects, or even its existence, amongst the
general public, the common view of many scientific communities
(DEFRA 2007, IPCC 2007, UNFCC
2010)
is
that
the
anthropogenic
2012, Hester and Harrison,
carbon
emissions
and
other
Greenhouse Gases (GHG’s) are having a severely harmful effect on
the environment. This paper takes that view.
There have historically been extreme climatic changes which have
caused events such as Ice Ages, but it the rate at which these
current changes are occurring that is causing concern. The fourth
IPCC report (2007) concluded that in the 8000 years before 1750
the carbon dioxide concentration in the atmosphere increased from
260 to 280ppm, and increase of 20 ppm. Over the subsequent 260
years
the
concentration
increased
by
over
100ppm,
a
rate
of
increase 154 times faster.
10
1.1;
Figure
Keeling’s
recordings
of
atmospheric
CO2
concentrations between 1957 (320ppm) and 2000 (372ppm). Levels
have since risen to 397ppm in 2012. ( taken from Fitton 2011)
All
previous
shifts
in
CO2
concentration
have
corresponded
to
significant environmental and climatic shifts. Levels this high have
not been present for millions of years and there are concerns that
few organisms that
have the ability to withstand further
rapid
changes. These figures have resulted in an increase in the number
of investigations examining this field .
The current aim is to stabilize levels at 450ppm, whilst currently
rising at 2ppm each year, this level is expecte d to be breached in
less than 30 years (Hester and Harrison, 2010)
1.2.1 Greenhouse gases
Whilst CO2 levels are the most commonly mentioned in the media
and often in publicised investigations and mitigation strategies,
gases such as methane or sulphur dioxide have a significantly more
insulative effect in the atmosphere than
CO2. Human activities
have increased the release of the volumes of other gases including
by having more animals for meat or dairy produce has significantly
increased
the
volume
of
methane
released
to
the
atmosphere
(Chapman, 2009).
However, the larger total volume and thereby overall effect of CO2
released each year is contributing more to the greenhouse effect
than these other gases. Figure 1.2 shows both increase in GHG
concentrations
in
recent
history
and
that
CO2
concentration
is
much higher than other GHG s, being measured in parts per million
rather
than
parts
per
billion.
The
figure
shows
historically
fluctuating rates, but emphasises that the rate of change is that
concerning scientists. This is why it is often the main focus for
reducing climate change impacts.
11
Figure 1.2: Ice core data showing historic GHG levels. (IPCC,
2007a).
Carbon
Dioxide
is
the
major
contributor
to
GHG
emissions,
making up 86% of global emissions (DEFRA, 2006). The release of
CO2 is part of the carbon cycle, which can take place on many
levels, over minutes or over thousands of years.
This balance is
being altered by human practices such as deforestation and burnin g
fossil fuels, preventing long-term storage of carbon and releaseing
large amounts of CO2.
1.2.2 What is being done
The Kyoto Protocol to the United Nations Framework Conventi on
on Climate Change, adopted in 1997 and becoming legally binding
in 2005, was designed for 128 committed parties to work together
towards stabisiling atmospheric GHG. The aim is to achieve this by
both
reducing
atmosphere
by
total
emissions,
enhancing
carbon
and
removing
capture
and
CO2
storage
from
the
methods
(IPCC, 2007)
12
Figure 1.3: The carbon cycle, showing how human activities affect
the balance. (Scottish Centre for Carbon Storage 2012)
In the wider environment, carbon is cycled over various timescales
with both short-term such as those in detritus and deciduous leaves
on trees, and others long-term such as coal or other fossil fuels. As
increasing amounts of fossil fuels are used for energy production,
the overall volume of
carbon being stored in these reserves
is
depleted. The resulting emissions in the atmosphere lead to the
climatic changes being observed (Figure 1.3). The current global
dependence on fossil fuels is being addressed with much focus on
renewable energy sources, but it has faced numerous obstacles,
including
global
recession
and
lack
of
funding
for
affordable
technology (OECD, 2009).
This study investigates carbon capture and storage (CCS) on a
small scale in the UK with a case study on Leckford Estates, n ear
13
Southampton (51:07:60N, 01:28:02W). The cycling of carbon on a
farm limits that part of the carbon cycle being examined (Figure
1.4).
Figure 1.4.
In an agricultural carbon cycle, the release of CO2 is
proportionally lower as there is more production of methane and
nitrous oxide. (Farming Future 2012)
The need for improved carbon storage
Reduction
of
government,
carbon
business
emissions
and
has
individual
been
agendas
the
for
top
a
of
many
significant
period of time due to international action and increasing public
awareness and pressures. Whilst it remains a top priority, these
changes
potential
are
considered
impacts
of
insufficient
climate
by
change.
scientists
to
reduce
Modeled
predictions
the
of
14
climatic changes suggest there is still going to be an increase in
average
global
temperatures
even
if
global
emissions
cease
overnight, due to the lag effect (Blasing, 2009; Letiman, 2006).
Figure 1.5: A number of scenarios dependent on future emissions values
from 2008. (IPCC 2007a)
Carbon dioxide is one of the ‘easiest’ gases to tackle due to its
large volume and easily identifiable sources. Strategies such as
energy saving light bulbs and electric cars ar e marking movements
towards
combatting
already
occurred
emission
such
as
levels.
reducing
Other
GHG
CFCs
in
changes
have
aerosols
and
refrigerators, though other gases are harder to reduce or remove
entirely. For example, one of the GHGs produced on Leckford is
methane, from the onsite dairy herd. There is the ongoing demand
for milk and there are very limited ways in which emissions can be
reduced
without
harming
the
production
of
the
herd.
Other
methods of reducing the net effect of the site ’s contribution to
climate
change
are
therefore
being
examined.
These
include
initiatives such as using wind and solar energy to power chicken
barns
and
recycling
of
manure
to
retain
nutrients
and
organic
material in the soil.
15
Whilst these practices are still to be encouraged, and is the main
priority of initiatives, there is another option to be explored . To
attempt
to
emissions
compensate
there
is
for
the
potential
reported
to
increase
deficit
the
in
reduction
carbon
storage
of
in
biological features of the environment. Carbon is naturally stored
by biological material and plants will take in carbon dioxide and
store the carbon as part of their structure. Some of these areas
have huge potential such as the sea, woodlands and soil, mostly
due to the huge volume of the planet th at they occupy (Rackley,
2010).
By manipulating or encouraging CO2 uptake by plants, there is the
potential to further reduce the total volume of emissions reaching
the stratosphere after being released in our lower atmosphere. This
would add to current efforts to reduce carbon emissions. As set out
in
the
aims
of
the
Kyoto
Protocol
forests
are
identified
as
a
significant target for CCS. These biological carbon sinks should be
afforested, reforested and rates of deforestation reduced in order
for
committed parties to met their
reduction
aim
to
(Rackley,
increase
2010).
the
targets
Afforestation
volume
of
for
and
woodland
carbon
emission
reforestation
available
be
both
either
increasing the area, or improving the current areas of woodland
respectively. A sink provides a source of storage for carbon where
it is held for a period of time, temporarily or semi -permanently
removing it from the carbon cycle. Due to this initiative by the
Conference of the Parties; Kyoto Protocol, improvements to forest,
expansion
of
forests
and
soil
carbon
levels
have
all
been
recognised as legitimate climate policy measures , as part of the
global strategy to combat climate change.
Methods are being explored for agriculturally based sequestration
of carbon in sinks, focued currently on examining the potential of
soils and woodland holding carbon inactively for extended periods
of time, some using artificial products such as BioChar (Ahmed et
al., 2011). Biochar is not considered in this investigation beyond
being a developing method for storing carbon in the soil. It renders
16
carbon into an inert form and can increase the topsoil storage of
carbon from 100 to 250tCha-1(Lehmann, 2006). Around 50% of this
carbon remains in the soils after 5 years compared to 10% retention
by the addition of plant material , which decomposes more easily
(Lal, 2008).
The
potential
benefits
of
increasing
soil
carbon
come
at
comparatively low financial cost, making management plans for
agronomic improvement and nutrient management very promising
options because of their impact on overall N2O and CO2 emissions
(Fitton et al, 2011).
Conservation plans have given the theory much more appeal, as
record levels of sequestration occurred in 1993, coinciding with
the
introduction
of
set-aside
(Naylor,
2012).
Set
aside
is
the
practice leaving a margin out of cultivation at the edge of each
agricultural field to increase habitats for many farmya rd birds and
wildlife corridors (Bell et al, 2011). The importance of careful
management
potential
of
of
agricultural practices and shows the developing
biosequestration
if
implemented
and
understood
correctly is highlighted. This supports conclusions that
manure
application, informed use of fertilisers and adoption of scheduled
crop rotations benefits agronomic outputs whilst also enhancing
the soil organic carbon pool (SOC) (Sparkes, 2005). Manure, unlike
chemical fertilisers, enhances SOC due to the additional input of
carbon.
It
also
leads
to
improvement
in
soil
quality
and
improvements in aggregation and structure, improving the overall
health of the soil and its ability to hold organic material
and
carbon. Adoption of no-till on-farm conditions has led to similar
sequestration rates to research plots in accordance with Fittons
model of sequestration potential. (Jarecki et al, 2005; Fitton et al,
2011)
1.3 CASE STUDY: Background to Leckford Estate.
Leckford
Estate,
near
Stockbridge
was
purchased
in
1928
and
designated as an experimental farm for the production of products
for Waitrose. Leckford Estate currently report their total carbon
17
emissions
to
companies
Waitrose
total
as
net
part
of
emissions
a
scheme
and
to
identify
summarise
problem
the
areas.
Businesses are currently aiming to curtail the recent exponential
increase of CO2 emissions and mitigate them. Leckford currently
generates around 2% of the company’s carbon footprint , and aims
to
reduce
their
net
volume
of
GHGs.
The
gases
emitted
are
recorded as carbon equivalents, showing the proportional effect
each
action
activities.
is
The
having
major
on
the
output
total
is
the
outcome
dairy
of
farm,
the
farming
from
methane
production by cattle and an additional major contribution is made
by the addition of synthetic fertilisers, m ostly occurring between
Feburary and May. The total tCO2e tonnes of CO2 equivalent is
7705 for Leckford Estate in 2011 -2012, with 32% of this coming
from
the
dairy
hard
and
another
23.2
being
produced
by
urea
provides
this
sulphate.
The
estate
is
an
extensive
mixed
farm
and
investigation with the perfect location for a case study to identify
major areas where carbon storage is currently occurring, and areas
where these figures could be increased . This study aims to examine
the
current
purchased
storage
and
of
used
carbon
as
an
on
this
site,
experimental
as
it
project
was
initially
to
promote
environmentally friendly practices and explore new methods and
technologies
and
enhance
the
understanding
behind
many
agricultural practices.
There are currently a number of schemes taking place on Leckford
Estates to attempt to reduce to overall carbon footprint of the site,
as required by the Waitrose business plan and inkeep ing with their
‘green’ image. Some of these include;; reusing dairy and chicken
waste as manure on the fields, along with any green waste from
mowing lawns, pruning trees of removing weeds from the parkland.
The site currently undertakes such measures as recycling, increased
use of renewable energy and composting organic waste left over
from
growing mushrooms to
improve its sustainability
(Sparkes
2005, Moral 2009).
18
Currently
pressure
is
increasing
from
governments
and
wider
business plan initiatives are becoming available. Due to pressures
on increased corporate responsibility Waitrose have produced their
own green business plan to address their GHG emissions (Waitrose
2012).
Supermarkets
currently
face
a
very
competitive
industry
where the public expect low prices for food, yet also responsible
actions in their production (Seyfang 2009, Jackson 2006). Waitrose
need
an
affordable
way
to
carry
out
positive
actions
for
the
environment and have already gained LEAF and Soil Association
accreditation.
1.4 Idea of project and purpose of study
Biosequestration was chosen as the focus for the investigation as
the site has many pockets of woodland and vast areas of hedgerow
and undergrowth. Due to the nature of the site, and inkeeping with
its image of forward thinking and experimentation, areas w here
vegetation
was
(biosequestration)
actively
were
to
uptaking
be
and
sequestering
investigated ,
and
allow
carbon
a
more
balanced idea of the net carbon footprint of the site. The estate’s
carbon footprint was modeled in 2010 , showing current emissions
of 389,969tCO2e in 2011-2012, increased from 2010-2011 figures of
386,082.
This
shows
that
is
is
vital
for
Waitrose
to
cut
their
emissions and enahance carbon stores anyway possible.
Areas of carbon sequestration on the site were to be identified and
any potential to increase these values were to be examined and
suggested as appropriate. Waitrose aim to double the size of their
business by 2020, however they intend to do this whilst reducing
the overall CO2 footprint of the company by 15%, compared to the
2010 baseline. This investigation aims to identify areas where the
company can aim to meet these targets on Leckford Estates by
changing practices and increasing the volume of carbon stored on
their land.
19
1.5 Significance of the study to the field
There is growing recognition for the role that this resource could
contribute, as a significant quantity of soil carbon and woodland
storage were lost previously due to a spread of intensive farming.
Currently there is less of a need to retain good quality soil as
fertilisers
became
more
readily
available.
Now
climate
change
implications as well as biological and ecological implications are
becoming
more
Environmental
and
more
prominent
Stewardship
Program
with
projects
quantifying
such
these
as
the
resources
and making reccomendations by which they can improved (Carmela
et al, 2011;
Zhang
2007;
et al,
Aluaro-Fuentes,
2012).
This
is
particularly important for the future by increasing food production
sustainability in the attempt to provide for exponential rises i n
population. If the results of this field of reasearch became more
accessible
to
farmers
and
business
owned
it
could
provide
a
reference point by which they would be able to understand and
implement carbon sequestration measures.
As discussed later in the literature review, this study was difficult
to undertake as the existing resources are not available to simply
input the figures into a model for something of this scale. There
are a range of detailled models that enable the estimation of the
carbon footprint of a tree or entire forest. However, estimating
small areas of mixed woodland is, as yet, something not considered
as
a
significant
area
for
research.
Whilst
each
woodland
contributes a comparatively small volume of carbon, by optimising
this storage huge global changes could occur. A blanket calculation
was considered to summarise the sites CCS but this was determined
to be insufficient due to the great differences in management and
nature of existing models, as discussed later.
Woodlands and soil can contribute huge volumes of carbon storage
in the mid-term and long-term and are an invaluable resource in
the
current
battle
against
climate
change.
Specific
areas
of
20
woodland on the site are to be assessed for current carbon storage
potential, and management plans tailored where appropriate. The
soil in particular is an area of interest for future study, having
been depleted of natural organic content . By increasing the soil
carbon
storage,
the
need
for
fertilisers
should
decrease,
also
decreasing the net carbon footprint as inputs are reduced.
There are many complex aspects to the carbon storage cycle and
the modelling of this in trees and soil is even more so , this study
attempts to simplify them to a manageable form to be understood
by a wider audience allowing relevant departments at Waitrose to
form a management plan. There are some aspects currently not
considered in the model such as the cycling of dead wood, which
could be considered in the future and have large potential in the
full net carbon exchange but have beened deemed beyond the scope
of this investigation due to time and resource constraints.
2. Aims and Objectives
2.1 Aims

Identify sites of carbon sequestrations on Leckford Estate.

Compare sequestration to emi ssions

Give a figure for each woodland in terms of carbon storage
undertaken.

Construct a carbon storage map of the site with current
storage levels, predicted levels without alterations and with
changes to improve carbon storage.

Identify areas where practices and processes can feasibly be
altered to improve the carbon sequestration of the site .
These
could be applied to other sites, expanding the relevance of the
project and forming the backbone of a management plan aimed at
climate change mitigation.
2. 2 Obj ecti ves

Design a method by which the carbon storage could be
quantified and compared across the different woodland sites.
21

Construct a model allowing the effectiveness of carbon sinks
to be evaluated and quantified, examining outputs associated wi th
practices and predicted improvements to C storage.

Construct a GIS map to visually inform stakeholders of
potential areas that can hold more carbon to accompany the
resulting values calculated.
3. Literature Review
The growing problem of Climate Chang e
Despite
many
organisational,
governmental
and
individual
best
efforts, there is a continual increase in GHG concentration the
atmosphere due to human activities. Levels have increased from
260ppm
before
1750
to
297ppm
in
2012
(ESRL,
2012),
despite
increasing awareness occurring since the 1970 s. Figures 3.1 and
3.2 show how total volumes in the UK and EU of GHGs ha ve
decreased from 1990, but the increasing emissions of developing
countries have lead to further increases.The insulative properties
of these molecules cause heat entering the atmosphere to become
trapped in the air, hence the common term of ‘global warming’.
This term is slightly misleading with ‘Climate Change’ being a
more accurate term.
600,000
Volume of UK GHG emissions 1990-2010
Gg CO2 equivalent
500,000
400,000
300,000
1990 Volume
200,000
2010 Volume
100,000
0
CO2
CH4
N2O
Greenhouse Gas
Others
Figure 3.1: A comparison of GHGs released in 1990 and 2010
22
Figure 3.2: Composition of data showing CO2 being the dominant gas
produced by all countries and the EU when combined. (UNFCCC, 2012)
Climate is understood to be around a 30 year average of weather
conditions of an area, and weather is that is occurring over a much
shorter period (Favier, 2012). The changing of the climate due to
substantial and long term differing wind patterns, rainfall levels
and
average
compared
to
temperature
1980s
are
averages
already
and
being
have
seen
adverse
to
be
effects
present
on
both
people and the wider environment (IPCC, 2007, Naylor 2012). 2012
has so far been the wettest UK summer on record and indicates
future
climatic
shifts.
For
example,
a
number
of
high
altitude
butterfly species in Britain are observed to have moved north by an
average of around 6.6km and fish species are changing their depths
of breeding and occupation by between 50m-200m which can have
severe effects on population patterns and survival rates of young
(Bush, 2012). Climate change will also have wide reaching effects
on many species that have become specialised to a niche habitat.
These niche species may be reliant upon the plant life found there,
which may alter it’s own habitat boundaries in a different direction
as certain areas of the planet will warm faster than others. If a
species cannot adapt quickly enough or move with that which it
relies upon to survive, it will become extinct. There are many
vulnerable species at risk of extinction due to their niche hab itats,
small
numbers
and
limited
ranges
including
plants
which
have
23
much more limited ranges than animals . Loss of these species have
great
implications
potentially
for
future
undiscovered,
biodiversity
keystone
as
ecological
well
as
services
many,
(Naylor
2012).
Biodiversity is difficult to value in monetary equivalents and the
changes in composition that the environment will see may have
many
unforeseen
and
potentially
devastating
consequences.
Irreplaceable habitats may be lost and vital ecosystem serv ices
such
as
the
water
cycle
may
be
disrupted.
Climate
change
is
estimated to have severe effects on humans for numerous reason
including food production and water availability, and Waitrose is
one of the many food providers concerned as to the effects and
attempting to counteract them.
Volume of emissions of different GHG's
in the UK, 2010
2%
CO2
CH4
N2O
Others
9%
12%
77%
Figure
3.3:
Volumes
of
UK
2010
emissions,
showing
CO2
as
the
predominant gas. (UNFCCC, 2012)
Governments
are
required
to
reduce
the
outputs
of
greenhouse
gases, which contribute to heat retention in the atmosphere. Many
projects, plans and policies have been put into place to attempt to
combat these effects and slow the rate at which they are occurring
(Seyfang, 2009). The Kyoto Protocol identified key emissions to be
tackled by each ratifier but many have chosen to focus on CO2 as a
main contributing factor because a reduction in carbon emissions
24
can lead to beneficial knock-on effects such as a reduction in other
gases.
These pressures on government s, combined with increasing public
awareness
of
environmental
issues,
ar e
affecting
proposed
developments of many businesses, in terms of their future practices
and
areas
of
growth.
There
are
more
environmental
guidelines
regarding mitigation measures that can , or must, be used to reduce
environmental impacts. Many of these fo cus on climate change,
following
the
recommendations
by
bodies
including
the
IPCC
(2007) and advice formed in the Kyoto Protocol (1997). There is
also
increased
pressure
from
groups
such
as
Greenpeace,
and
public opinion is changing to a ‘greener mindset’ with more being
expected from companies’ contributions to tackling climate and
sustainability issues (Seyfang 2009, Jackson 2006). These actions
are expected to be immediate and many businesses are publishing
ways by which they aim to reduce their carbon f ootprint or foodmiles, such as Marks and Spencer’s ‘Plan A’ and Sainsbury’s aim
for sustainable fish stocks in 2010. Waitrose have had strong focus
on increasing the efficiency of their stores and have changed their
method of refrigeration to reduce the overall GHG emissions of
their stores and now aim to tackle other areas
(JLP Corporate
Responsibility Report 2010).
3.2 Agricultural Carbon Storage and sequestrations (CCS)
The 2011 DEFRA report into agricultural em issions concluded that
nitrous oxide (NO2) and methane (CH4) were the main contributors
of
GHG
emissions
from
UK
agriculture.
The
main
cause
of
agricultural nitrous oxide emissions is from synthetic fertilisers
added to arable soil, and methane emissions result from animal
digestion and manures. All carbon dioxide is deemed to result from
fossil fuel consumption for energy uses (UNFCCC 2012, DEFRA
2008). Total emissions for the agricultural sector have been falling
since 1990, and there are ongoing efforts to continue to reduce
these levels and DEFRA believes this will continue to happen, but
at a reduced rate. Potential for carbon storage to counteract these
25
emissions from energy consumption is currently being explored as
agriculture and land use currently contribute 9% of the UK’s GHG
emissions, and 14% of global emissions in 2002. Any reduction will
assist in minimising the overall effect of climate change and could
improve the effectiveness of the industry (DEFRA , 2011; OECD,
2002).
Volumes of agricultural GHG's released
2010-2011
Nitrous Oxide
9%
Methane
36%
Carbon Dioxide
55%
Figure 3.4: A chart to show the proportions
emissions produced 2010-2011. (UNFCCC 2012)
of
agricultural
This investigation wishes to investigate the potential for carbon
storage, as although not a major agricultural emission, it is the
largest globally and farmland has high potential for altering carbon
storage.
The
estimated
mostly
due
to
emissions
of
individual
different
reference
products
systems
or
vary
greatly,
selected
system
boundaries. Some studies compare different agricultural production
systems (Luo, 2010: Sparkes 2005) and focus only on part of the
process, while other surveys consider the who le life cycle (DiazHernandez, 2012). Per unit, (kg/CO2 per kg/product) there is a
diverse range between different agricultural practices with some
promise as methods of reducing or storing carbon emissions. For
the
purpose
of
this
component
examined
assessment
would
be
investigation,
in
terms
needed
of
as
carbon
storage,
many
wi ll
a
output
be
full
the
life
emissions
only
cycle
can
26
countered using a blanket approach for all GHGs (Robertson et al.
2000; Smith et al. 2001; Gregorich et al. 2005).
Figure 3.5 Economic potential of a number of land management
practices. (Fitton 2011)
This chart shows set aside has limited effectiveness at the lowest
financial inputs compared to agronomy and nutrient management,
but the greater financial inputs provide greater outputs.
Fitton
et
al
(2011)
compiled
a
number
of
investigations
into
sequestration of different types of cropland, and found there is a
wide range of values that could be achieved, with full poten tial
values
ranging
from
0.51
CO2
(tonnes
CO2/ha/year)
using
agronomy through to 3.30 CO2 (t CO2/ha/yr.) when the land is
converted to set aside.
3.3 Carbon Sequestration in Trees
As
the
earth’s
forests
currently
contain
more
carbon
than
is
present in the atmosphere, it is instantly clear how valuable a
resource in the fight against climate change that this biological
sink is (Harrison and Hester, 2010). Since the agricultural and
industrial movements in the UK of around 1750, there has been a
considerable decrease in the condition and total area of forest. As
27
agricultural practices have become more i ntensive with improving
technology
the
potential
for
these
sinks
to
hold
carbon
had
decreased, causing a steady rise in the greenhouse effect.
This
is
now
being
tackled
both
nationally
and
globally,
and
between 1994-1999 the total area of EU forests expanded by 3%,
the equivalent of 1Mha being afforested (European Commission,
1997).
Increases were highest
in
the
1970’s
due to
a trend of
planting large volumes of fast growing coniferous plantations, but
due to objections concerning wildlife effects and societal impacts,
these rates slowed from 40Kha/yr to 10kha/yr and are predicted to
drop to 8kha/year by 2020 (Nijnik, 2010). This is a shaky step
towards a strategy that may halt the increase in climate change
effects around the world and prevent many millions of people and
entire species being severely affected. The UK has been recognised
as
having
providing
leading
financial
initiatives
incentives
into
and
carbon
storage
having
bodies
strategies
such
as
by
the
Forestry Commission and SEERAD to coordinate efforts (Nijnik,
2010; Countryside commission and Forestry Commission, 1996 ).
The earth is currently covered in around 4 Gigahectares of forests
(30% of the total land area) and these are estimated to hold 120Gt
of carbon. Forests contain approximately 77% of carbon stored in
land vegetation; the majority in tropical and boreal forests, and
the remaining 17% in temperate forests such as those in the UK.
These account for 90% of the annual exchange of carbon between
the atmosphere and the land (IPCC 2007). Their growth is one of
the
few
natural
ways
of
removing
and
storing
CO2
from
the
atmosphere, making them an invaluable resource in the attempt to
counter climate change. Forests also play vital roles in the water
and GHG cycles, which is of particular interest in the UK for
sustainability (Seyfang 2009, Nijnik and Bizikova 2008). There is
much variation in woodland carbon storage within the UK, with
northern coniferous forests shown to hold twice as much carbon as
southern broadleaved woodlands (Forestry Commission 2009).
28
Biosequestration is the process by which carbon is stored in the
living material of plants and trees. As some trees can store this
material for decades or even centuries, it is considered a m id-term
storage solution. Short-term stores would consist of annual plants
such as nettles and long-term storage solutions would be inactively
held in the soil or by the accumulation of material into fossil
fuels.
Trees absorb atmospheric CO2 by photosynthesis and over their
lifetimes
they
absorb
more
carbon
than
is
re-released
(Nijnik
2010). The absorbed carbon goes to form the biomass of stems,
wood, branches, leaves and rooting system. Once the carbon is
incorporated into the tree a large proportion of it is lost in the
same year through root cell sloughing and the yearly loss of leaves
by deciduous trees as part of the natural lifecycle of the tree ,
providing
a
method
by
which
this
biomass
can
enter
the
soil .
Carbon in core wood is stored for long periods of time but exactly
how
long
growing
for
depends
conditions
and
heavily
any
on
forest
the
tree
species,
management
individual
present
(ECCP,
2005).
No
store
of
forest
carbon
is
viewed
as
permanent
due
to
the
eventual cycling of carbon that occurs as trees grow and then die
(Tipper et al, 2004). But if an area of woodland remains in place as
a permanent landscape feature, a level of carbon is permanently
stored in this area. By improving the rate stored and the area of
woodland designated as long standing, carbon sequestration levels
can be maximized. To do this the area would need the opportunity
to meet this full potential from good nutrient supplies, water and
amenable weather conditions. There are also chance occurrences,
which cause the loss of entire trees such as disease, or forest fires
that must be avoided when possible.
There is, amongst some, an assumption that all forests approach a
carbon saturation point upon maturity and they stop storing more
carbon (Fitton, 2011). When the individual trees die, some of the
biomass remains in the forest and is held in the soil, to be taken up
again by the trees or held there passively. This is a complex issue
29
as
afforestation
decomposition
can
and
release
the
soils
carbon,
beneath
the
due
to
canopy
also
deadwood
have
the
potential to lose carbon as the rooting systems of previous grasses
decompose (Gregorich 2005).
Current
evidence
shows
that
the
most
efficient
and
effective
method for balancing C storage and biodiversity is to allow forests
to reach maturity, ensuring they are of a good size, with good
wildlife
corridor
links
to
provide
good
species
circulation
and
adequate cycling of nutrients within itself (Naylor, 2012).
Figure 3.6 Showing the different rates at which different trees
sequester carbon in a number of European countries (tCha -1yr-1).
Coome, (2012) examines the complex relationship between carbon
storage and the lifecycle of a forest and shows how difficult it is to
predict future patterns of growth. This is because trees will alter
their growth patterns depending on the individual circumstances,
perhaps
due
to
old
stands
falling
and
allowing
great er
light
30
penetration or competition from new growth. It is concluded that
these
events
would
increase
without
sufficient
woodland
management.
Reforestation and afforestation are already showing their potential
as carbon sinks as well as some old growth forests due to the high
levels of carbon they store, (Coome, 2012). There is still a large
store with broadleaf woodlands in the UK able to store u p to
250tCha over their lifetime (FC, 2008). Levels stored each year
very greatly according to climate species and age of tree, but for
UK mixed species farmland it is estimated 3.2tCha -1yr-1 is stored
as demonstrated in Figure 3.6 (Crabtree 1997)
3.4 Methods for measuring car bon sequestration in trees,
This is still a particularly evolving field with much investigation
into a range of factors such as the amount of carbon an individual
tree will take on each year, to an entire rainforest’s potential for
carbon capture.
3.4.1 Satellite imagery methods
A
number
of
approaches
have
been
undertaken
for
mapping
forested areas to determine their annual growth and correlated
carbon storage. One was using satellite images to determine height
and volume of trees. This has been done successfully in a number
of areas in the UK including Wales and East Anglia (Balzter et al,
2003; Bateman et al 2009), but involved examinations of areas of
coniferous
plantations
where
planting
ages
were
known
and
dimensions were shown to have strong correlations to age. Models
can be made to study the reflectance of the canopy of a forest to
examine
the
density
and
health
of
a
forest
or
particular
wavelengths can be used to examine the volume of trees in the
forest, but these methods require advanced modeling skills and a
sizeable
data
set
with
which
to
conduct
it.
Due
to
the
heterogeneity of the sample this was not an option and due to the
time limits of the investigation, preventing a long -term image of
how much growth was really occurring.
31
3.4.2 Models using species coefficients
As many of the models in the UK have used satellite-monitoring
systems there is a deficit in figures available to calculate carbon
storage without use of satellite imagery. Due to the investigation
being non-invasive, the number of models available became rapidly
limited and the majority of co-efficients available with which to
calculate were based on American climates. A number of British
species were without exact coefficients, so those for the nearest
relative
were
used
(e.g.:
for
Sessile
Oak,
used
White
oak
coefficients). In an examination of German tree growth, American
coefficients
were
used
and
deemed
to
produce
relevant
figures
showing the transferability of this technique and its current usage
(Strohbach, 2010). This gives a fair basis for tree biomass based on
physical
created
calculations
would
allow
alone
that,
once
basic
physical
a
basic
inputs
to
spreadsheet
be
made
was
and
a
comprehensive carbon analysis to be undertaken.
3.4.3 Online modeling programs
There are currently a number of online c alculators available that
aim to calculate the net emissions of a site by examining
CO2
sources such as farm vehicles or fertilisers used and balance them
against CO2 storage undertaken by any areas of woodland. There
are little detailed inputs for these , and the final figure produced is
based on these figures. This method, for such a diverse site , was
deemed
inappropriate,
as
many
aspects
affecting
sequestration
efficacy need to be included in the model. These include; richness
of the soil, tree species and seeding density. These models do
however allow complex calculations to be carried out with minimal
knowledge required by farmers (Smith et al ,2008, COOL calculator
2012 , CALM calculator 2012).
32
The CALM and COOL online calculators are both useful tools for
rapid
calculation
of
average
results,
but
the
age
of
trees
is
required, which is unavailable for many areas of Leckford Estate.
In addition, these models did not consider the density of trees . A
rough
estimate
of
ages
of
the
trees
can
be
obtained
from
the
physical figures and management plans, but as the size of the trees
was not
thought
to be affected by age, more
condition
of
the
woodland, this was deemed not to be the most accurate method
available.
3.4.4. Selected Model
The final model selected to measure annual rates at which carbon
was being stored was chosen on the basis that individual trees
could
be
entered
and
analysed
separately
(Clark,
1986).
In
addition, as the exact age of each individual tree was not known,
this was a method by which the physical characteristics of the tree
could be taken into account and examined in situ. The dimensions
of the tree and density of the forest could be calculated and used
as an up to date representation of carbon storage. These figures
were initially examined using a model where coefficients were used
for each type of tree, but was based upon estimates of age rather
than the actual development of the tree , reducing the accuracy and
causing it to be disregarded.
Densely growing forests will have narrower trunks as the trees
compete for light, compared with than those sparsely planted trees
such as in the Parkland who have no such limits on the amount of
sunlight
that
they
receive.
For
this
case
study
a
method
was
required that accommodates the rich diversity in woodlands found
on Leckford estate and could accommodate the number of species
and range of densities found (Clark 1985).
3.4.5 Application of different models
The method selected could be implemented in the field without
destructive techniques
or knowledge of the age of the trees, a
requirement for online calculators. The site consists of many small
33
areas of woodland and removing areas of trees for examination
would severely damage the ecosystem. The method selected allowed
simplicity
of
the
model
to
be
understood,
repeatability
as
the
woodlands would be allowed to natural ly develop and accuracy
following from previous investigations.
Each
model
has
their
own
strengths
and
weaknesses
as
trees,
despite being the same age, will not always grow at the same rate
due to competition, differences in water, nutrient availability and
animal
activity.
examine
each
However,
tree
on
a
individually
large
and
scale
it
results
is
are
impossible
to
appropriate
if
average values can be used provided they retain accuracy (Shirima
et al, 2011) .
The
complex
models
available
for
large
areas
of
woodland
(Bateman, 2009) usually monitor the growth of for ests consisting
of one species as they are similar ages in a commercial forest.
These are useful models and show the most promise for the future
for scientific analysis, but they do not easily accommodate a range
of species at a range of different ages, as is the case at Leckford .
They are also not easily understood by those on the farm as both
the
modeling
skills
and
technical
knowledge
are
advanced
and
impractical for a basic assessm ent of carbon storage each year on
the small site.
Future
modeling
of
carbon
storage
is
more
complex
due
to
inclusion of climatic conditions and soil type. As the exact age of
each tree is unknown, more general calculations must be made
according to the current growth of the tree, but this makes it less
reliable. The figures represent the expected growth of the tree
provided that it continues to grow at a standard rate , along with
its neighbours. The complexities of woodland modeling mean that
stands could perish and competition from other trees could reduce
the
expected
particular
growth
year,
only
rate
as
but
a
these
likelihood
cannot
be
rate
( e.g.
predicted
1
in
50
in
a
year
probability) (Coome, 2012)
34
3.5 Soil Carbon Storage
Soil
is
recognised
as
a
significant
global
resource
for
storing
carbon, predominantly due to its volume. Carbon storage in soils is
a natural process occurring when atmospheric carbon dioxide is
fixed into soil, whilst some is held there in a relatively permanent
form. Sequestration implies both the process of capture and storage
of carbon in soils in this case. The CO 2 must be converted to
another chemical form to be held within the soil , usually organic.
Sinks can vary in size, potential and the duration that they hold
CO2. The Forestry Commission report that UK soils can hold up to
4
times
as
much
carbon/ha
as
a
UK
woodland,
making
it
a
potentially more valuable resource (FC, 2012).
There
are
a
number
of
differ ent
natural
pools
that
carbon
is
naturally stored in, with varying volumes of carbon that can be
stored within. Oceans have the most potential and there has been a
recent
shift
in
balance
between
the
atmosphere
and
biosphere
pools, the effects of this are currently hotly debated as to whether
the biosphere will grow to accommodate this increase ( Bateman,
2009)
Name of mobile pool
Quantity of carbon held
annually (Petagrams/ Pg)
Atm osphere
800
(600 before the 1750)
Biosphere
600
Soil
1,500
Ocean
39,000
Table 3.1: Quantity of carbon held in mobile pools
Terrestrial results are easier to implement as the mixing of layers
and the volume of which this occurs are much smaller, thus the
outcome of an application of BioChar is more easily predicted than
35
the attempted iron fertilisation of an area of ocean (Strohbach,
2010).
There
are
two
cycles
of
carbon
within
the
soil;
organic
and
inorganic. Inorganic occurs more rarely and involves the formation
of carbonates that are long-term deposits (Wilding et al, 2001).
Organic carbon is of far greater importance on a global scale as it
dominates
the carbon
volume
within
the soil,
although
it
is a
shorter-term deposit (Lal, 1997).
The
atmospheric
carbon
is
firstly
fixed
into
plant
material,
complex compounds that enter the soil when the plants die. These
compounds are broken down by the action of soil microorganisms ,
which re-release the carbon back to the atmosphere . Almost all
plant
material
entering
the
soil
will
be
cycled
back
to
the
atmosphere (Alvaro-Fuentes et al, 2012). The annual carbon volume
cycled
is
heavily
reliant
upon
plant
productivity.
On
a
global
scale, fixation of carbon within the soil is around 120Pg (1Pg
being equal to a gigatonne), with half being immediately returned
to the atmosphere after roots and shoots respire. The remaining
60Pg is able to enter the soil (Chapman, 2009).
Upon entering the soil, the material is broken down with the least
complex
compounds
being respired initially ,
and
more
complex
matter being broken down over long er periods of time. Macro- and
Micro-fauna break the pieces down into smaller sizes, which are
degraded chemically by fungi and bacteria. The rate at which this
occurs varies the soil surface to further down into the soil as the
components get smaller. The year’s deposition of organic matter is
not fully recycled over the following year as some pre-existing
carbon may be in a more degraded form . It could be many years
before it is all eventually recycled.
Naturally, the global cycle of carbon deposition and decomposition
is balanced (Chapman, 2009). Intensive farming has depleted the
organic
carbon
content
of
the
soil,
contributing
to
GHG
36
concentrations. With careful soil management it is hoped that more
organic carbon can be maintained in the soil and less intensive or
better-managed farming will allow it to remain there.
Some lignin and proteinaceous material from plant tissue is very
resistant to decomposition by the microbial biomass, which itself
forms 1-3% of the Soil Organic Material (SOM) (Wardle, 1992).
Melanins produced by some fungi add darkening pigments to the
soil, giving it a visually distinctive profile. Humi fication involves
the
random
organic
re-synthesis
matter
by
of
various
chemicals
bonds
condensation
of
the
deposited
reactions ,
forming
‘humus’. This gives the bonds a high resistance to decomposition
from further enzymic degradation. These compounds can also bind
easily
to
clay
protection.
particles,
holding
SOM
as
it
provides
physical
The humus allows more water to be held at surface
level and the surface is ideal for binding nutrients to, for easy
availability for
any plant
life, reducing the need for
synthetic
fertilisers.
The carbon content of the SOM is increased from the 42% found in
plant material up to around 58% (Hayes, 2001). This is a useful
store
provided
continue
to
agricultural
cause
rapid
practices
removal.
and
Not
soil
all
erosion
carbon
do
added
not
to
a
particular soil is mineralised or decomposed in a year, but if the
length
of
the
cycle
can
be
increased
this
w ill
provide
more
effective storage. Fresh plant material can have a turnover time
ranging from months to a few years, but also plays the valuable
role of providing soil cover which helps keep soil temperature low,
soil moisture high and soil disturbance to a minimum (dependent
upon the season) which will all assist in improved carbon storage
(Zhang, 2007). Any soil organic matter taken further down into the
soil and protected by this plant matter layer can have a turnover
time of decades if it is associated with the mineral fractions, and
the most highly humified material can reside beyond a thousand
years and is considered ‘passive’ or virtually inert. There is not a
clear layering system within the soil due to organisms such as
37
worms and other animals so age distributions are often uneven
within the soil.
Currently, soil and water erosion are causing significant lo sses of
soil carbon of 0.6Pg each year , and there must be alterations to
these figures to increase carbon storage (Hope, 1997). A n overall
storage increase relies on more carbon being deposited each year
than is decomposed. However , the overall decomposition rate is
directly proportional to the amount of material that is present, and
the equilibrium of the system means that it is self-regulating and
will eventually reach a balance again whether stores of carbon are
increased
or
decreased.
Increasing
the
inputs
of
carbon
will
increase the total store permanently, as although equilibrium will
be reached again, the initial store level will remain hig her.
There are two way of increasing the carbon sequestration in soils.
1-Increase the rate of carbon input
2-Decrease the rate of decay of material
Globally, ploughing of the soil due to increases in agricultural
land has led to huge loses of carbon storage. Over 50-100 years
50% of the soil carbon can be lost to the atmospheric climate, with
losses being 50-75% over 10-20 years in the tropics (Lehmann,
2006). In theory, if this ploughed land was allowed to revert to
being a semi-natural ecosystem, the soil may be able to restore its
original level of carbon, yet in practice it has proved that levels
are lower over the same period of time, and a longer restoration
period would be needed. (Lehmann, 2006)
Soil carbon
is always slowly
accumulating due to the inert or
passive faction forming with soil carbon, and some soil scientists
believe that a true equilibrium state is never reached (Hope, 1997).
With current anthropogenic pressures, this is unlikely, but it is
true that many soils have a greater capaci ty to sequester carbon
than their current levels reflect.
38
The
local
climate
of
an
area
is
also
a
strong
influence
in
determining soil organic matter levels as decomposition rates are
increased
strongly
by
increased
temperatures
and
decreased
moisture levels, both of which will alter in areas due to climate
change.
3.5.1 Management methods to improve soil carbon
One way of increasing inputs into the soil is increasing the plant
matter inputs into the system. In arable systems this would involve
using cover crops or ‘mulching’, which reduce the time the soil is
laid bare, reducing exposure and erosion rate and leaving these
mulches in situ to allows composting (Forbes, 2006). Grass lay
systems are particularly important as they generate more biomass
underground, so a higher volume of carbon is instantly accessible
within the soil (Carmela, 2011). Recently mechanized cutting of
materials, although increasing use of fossil fuels, has shown that
residues
are
Hernandez,
more
2010).
efficiently
Another
being
returned
to
source
for
potential
the
soil
(Diaz-
increasing
soil
carbon inputs by adding biomass is by the use of non-phytotoxic
wood chips which are resistant to decomposition.
There is much agreement that improving the overall fertility of the
soil will increase both crop yields and the proportion of carbon
incorporated into the soil (Chapman, 2009; Smith 2004, Forbes,
2006). A meta-analysis showed correlation between increasing soil
carbon after increased rainfall and the use of cover crops. It was
also controversially linked to adding artificial nitrogen fertilisers,
which carry their own carbon budget of 1 -2kg of carbon for every
kg
of
fertilizer
although
the
biomass
of
the
area
is
increased
(Chapman, 2009). This was only proven in temperate climates and
requires
further
investigation
stored and emitted.
increasing
as
to
the
net
balance
of
carbon
Carbon levels in the soil were reduced with
temperatures
as
well
as
decreasing
quality
of
soil
texture, often associated with exhaus ted agricultural land. Sandy
soils gained carbon more quickly, as they had lower initial levels.
39
Soils
that
identified,
would
and
accumulate
are
carbon
primarily
most
rapidly
agricultural
soils
need
to
be
with
sandy
structures (Smith, 2004).
Ecosystem
Carbon Density
Carbon Density (UK) t
(Global) t C ha-1
c ha-1
122-123
-
96-147
170-370
247-344
-
99-236
130-230
80-122
120-250
Wetland
643
230-390
Deserts
42-57
-
Tropical Forest
Temperate Forest
Boreal Forest
Temperate Grassland and
Shrubland
Arable
Table 3.2: The carbon holding potential of selected ecosystems,
globally and in the UK. (Chapman, 2009)
Arable soils, being highly cultivated, often have the lowest soil
carbon of all UK land classes ( table 3.1), with grassland and then
woodlands containing subsequently higher levels and semi natural
environments including wetlands having the greatest potential for
carbon storage as peat land has the potential of holding
1,000tCha
-1
up to
(Chapman, 2009). Wetlands have a global potential of
sequestering 0.1PgC each year and restoration is encouraged where
possible to improve this natural long-term sink.
UK potential for carbon sequestration by restoration is 3070TgCyr-1, England’s potential being 9Tg. The UK potential is
therefore 6.6% of the 1990’s level of emissions (Chapman, 2009).
This potential may not be realised as more investigations examine
which areas have the option of undergoing practices such as zero
till, as they are not applicable to all soils. However, gradual
increase in soil carbon storage by reducing tills is certainly an
option to most areas.
40
Additional organic inputs, such as garden cuttings or slurry, would
also increase carbon sequestration. Although normal practice in
the UK, this may not occur elsewhere in the world due to the use
of these products as fuel. The UK has previously relied on timber
as a fuel resource and before the agricultural revolution, common
grounds were designated for providing fuel from peat or wood. The
shift to the agricultural revolution led to decreased areas of peat
and woodland available for carbon storage and the increase in
fossil fuel consumption alongside the global trend ( Wu, 2009).
As the human population has increased, so has the need for food
with which to support it. Tillage is the practice of ploughing or
cultivating the soil that has increased globally as more areas are
used for food production. This disturbance of the soil exposes the
contained SOM, which had previously been sheltered by the soil’s
mineral component. These changes in temperature, moisture and
increased
aeration
lead
to
stimulation
microbes,
increasing
soil
containing
the
decompose,
carbon
of
respiration,
the
any
and
carbon
detritivores
the
is
and
compounds
gradually
re-
released to the atmosphere more rapidly than the natural cycle . A
single ploughing of the soil can lead to 11% of the SOM being
removed, and continued tilling will increase this ( Smith, 2004).
The practice of ‘reduced tillage’ involves decreasing the number of
ploughing incidents, or ‘tine’ which involves ripping the soil using
discs, proven to be less destructive than previous methods (REF).
Ploughing
the
soil
repeatedly
can
reduce
soil
carbon
by
27%
whereas by using reduced tilling methods only 6% of the SOM
carbon
is
lost
(FAO,
2006a).
By
reducing
tilling
there
is
the
potential to increase Carbon by 2.1t ha -1 and the absence of tilling
would increase this further . Conservation tilling or mulching is a
slightly altered practice involving leaving plant residues on the
surface to retain moisture. Implementation of this practice in the
UK has proven to be limited with only 3% of the total arable land
adopting these practices in 2010 (Chapman, 2009)
41
By
enhancing
natural
processes
of
carbon
storage,
we
hope
to
create a more sustainable way by which companies and farmers can
produce enough food to support the growing population in the long
term (OECD, 2002, FAO, 2006b). Projections of 20 billion people
by 2050 means that radical changes are needed in the way food is
produced, as increased emissions may result in land becoming unfit
due to microclimate changes.
Globally
soils
have
lost
around
66
(+/-
12)
Pg
carbon
since
widespread cultivation led to forest removal and soil degradation
(FAO, 1998). It is still possible for similar amounts to be restored ,
but the need to sustain the current global population makes this
almost impossible unless new methods are developed. 0.4-1.2PgC
could be restored globally each year from the implementation of
zero till agriculture, representative of around 7% of global fossil
fuel emissions (FAO 2006a). Agricultural practices are becoming
more
intense
and
as
more
synthetic
fertilisers
are
added
to
stimulate plant growth, there is less need to ensure the quality of
the soil remains.
Soils
can
also
produce
other
greenhouse
gases with
significant
volumes of methane being produced by wetlands and peatlands but
the direct use of nitrate fertiliser has been shown to have the
largest
production
of
other
GHGs
in
Nitrous
Oxide
emissions.
Methane is 20x more effective as an insulator and nitrous oxide
300x more so in global warming terms than CO2. Again it is the
overall
effect
volumes
(FIGURE
that
are
3.2).
released
A
whole
which
contribute
lifecycle
analysis
the
largest
must
be
undertaken including other GHG emissions and fossil fuel usage to
be able to fully recommend practices for individual sites
Conservatively achievable levels give the UK a bleak picture as
although, theoretically, the UK is able to store 30-70TgC each year
using best practices, realistically only 4-6TgC is estimated using
achievable practices. In terms of actual targets, this is lower again
at around 1-2Tg of Carbon each year, as the greater population
42
density in the UK imposes constraints on available land and its
utilisation (Cannell, 2003).
There is little beyond a basic financial incentive for farmers to
increase the carbon storage of their soils and woodlands, and little
knowledge of new and sustainable beneficial ways by which to do
it. This soil sequestration potential could be reached after 50-100
years and due to the cycle of decomposition equaling the rate of
SOM formation, the rate at which this can take place will mean
strategies have decreasing benefit over time, as the cycle naturally
reaches an equilibrium. Other strategies need to be examined to
allow this to continue as a viable sink beyond 50 years and is an
attractive, cost effective option.
By taking arable soils out of cultivation a substantial increase in
soil carbon will occur, as shown by the correlated increases due to
set aside (Bell et al 2011). The exact rate and potential volume is
difficult to quantify but is still encouraged by the UNFCCC.
Hester and Harrison (2010) comment that all avenues need to be
explored, and carbon sequestration in soil will be only one of many
strategies aiming to reduce the current GHG burden of atmosphere,
but it has potential if it can gain enough backing. The FAO agree,
stating that agricultural soils, hold the potential to be one of the
largest global carbon reservoirs and hold potential for rapid carbon
storage due to rapid initial rates of sequestration in both soil and
woodlands.
3.5.2 Methods for measuring soil carbon
There are a number of techniques available for soil sampling both
the
organic
and
inorganic
carbon
content
of
soils.
This
investigation would focus on the organic content of soil, being
most
easily
sampling
altered
being
by
improved
available
and
practices.
the
Without
equipment
destructive
available
for
ionisation of samples the available tests available were reduced.
43
A basic Loss on Ignition (LOI) test was deemed sufficient to show
current health of the soil in terms of carbon content, and analyse
the composition of the soil, evaluating the types of soil. Whilst
this test, having errors in percentage content of between 1 -2% is
not the most accurate measure for SOM, it would be sufficient for
the purpose of this study in measuring relative levels held in the
soils.(Matthiesen et al, 2005)
The LOI method is used in a number of papers (Konare, 2010,
Smith, 2004, Reeuwijk 2002) and has been shown to have good
results and can be used in conjunction with a correction factor
where one is know (Konare, 2010), which was not applicable in
this case.
Critical analysis of methods
As some of the fields on site were particularly large and will vary
in composition, a range of samples is recommended to be taken,
allowing an average of the field to be taken ( Smith, 2004). As such
a wide range of lands uses and soils types are present, the decision
was made to sample as wide and diverse an area as possible, over
replicates within a field due to the restricted time frame. This
would enable better understanding of the wider picture of intrafield dynamics, which was of more importance to the investigation
than inter-field changes.
Samples were determined to be needed of the topsoils and sub soils
as these will differ greatly in composition. Topsoils receive plant
biomass
inputs
from
woodlands
and
grasslands,
but
suffer
increased rates of aeration in agricultural soils. By using LOI and
repeatable site measurements, this method provides a framework
for that which can be repeated in the future on the site.
Conclusion
44
Soil carbon is a valuable potential resource and, any methods by
which it can be restored would be beneficial. Even from this initial
investigation,
changes
can
be
suggested,
making
instant
improvements for a number of UK agricultural soils. The effects of
these changes can then be examined to see which are giving the
most improvements and adjustments can be made if a particular
soil type is less efficient at retaining soil carbon. Any increases in
carbon capture will have an immediate and worldwide effect as the
global atmospheric carbon dioxide level will be decreased by any
removal of carbon, no matter where it occurs.
Methods
Initial investigation of site.
An initial investigation of the site allowed the full scope of the
diversity and range between areas to be defined. It was decided
that the areas of permanent and designated woodland, as defined
by
the
GIS
Mastermap
of
the
site
(Appendix
1),
were
to
be
investigated for their current carbon storage as they are long -term
storage methods, which can be modeled for future carbon storage.
Another long-term storage component that was examined was the
soil on site (Appendix 2). The soil would be modeled over a longer
period of time, and again components enhancing carbon storage
could be identified and recommended. Le ckford Estate consists of
mostly Grade 3 agricultural soil that is fairly poor and does not
return
particularly
seemed
typical
of
high
most
yields.
Upon
agricultural
examination,
soils,
light
in
the
fields
colour
and
demonstrating little structure.
Leckford
contributes
gases
other
than
CO2
to
the
atmosphere,
which are calculated using carbon equivalent factors to gain a full
understanding of the GHG contributions of the site. This is beyond
the
scope
of
the
investigation
although
it
is
accepted
as
an
important area for future investigation.
45
It was decided to exclude hedgerows, undergrowth and windbreaks
from the woodland investigation and the different methodologies
that would need to be used would complicate the investigation and
was too much to investigate for the time available. To enable a
clear
and
focused
investigation
to
take
place ,
allowing
for
a
comprehensive understanding of the cycle taking place on site. 77%
of biological carbon storage is carried out by forests, giving an
excellent impression of a large proportion of the sequestration that
occurs each year (FAO 2006a).
4.2Woodla nd Sam pling Materials and Methods
4.2.1 Study area
Leckford Estate is located near Stockbridge, Southampton in the
UK (51:07:60N, 01:28:02W). The climate lies in a temperate zone
with a yearly temperature average of 11 °C, 700mm rainfall and
1550-1600 sunshine hours (Met Office, 2012). The natural climatic
forest
of
the
area
is
broadleaved
deciduous
woodland,
predominantly Oak and Ash (Leckford Management plan 2008).
On the site there are a diverse range of woodlands, many of which
have been planted with species not common to the UK. A summary
table
of
location
and
composition
of
these
sites
is
found
in
Appendix 1 and 1.1.
4.2.2. Sampling design and data collection
A stratified non-random sampling design was undertaken during
May and June 2012. Summer sampling allowed an establishment of
which
trees
were
living
and
assumptions
were
made
that
they
would survive until the next growing season. As leaves and buds
had emerged, allowed easier identification of species.
46
Woodland sites were selected sub-divided up if there were visually
distinct
areas
of
vegetation
or
class
designations
according
to
MasterMap. The sampling covered all ar eas of woodland on the site
but excluded hedgerows, deadwood and any undergrowth in the
form of shrubs or annual plants. These factors play a vital role but
were scoped out of this investigation due to time constraints .
The plot was subjectively selected as a representative sample of the
woodland and a 300m2 (30x10m) belt transect was used due to the
row
planting
structure
to
present,
be
and
explored
allowing
more
a
easily
gradient
than
a
of
the
forest
circular
plot
(Ravindranath & Ostwald, 2010; Guner et al, 2012). The species or
genus of the trees was determined and diameter at breast height
(DBH) was measured as set out by Ravindranath & Ostwald (2010)
following the protocol for estimating the above ground biomass as
far as possible without removing the tree.
4.2.3 Woodland Biomass Calculation
To calculate the biomass, the method set out by Clark
et al (1986)
was undertaken using allometric coefficients based solely on DBH
and height. These figures were slightly less accurate as they were
American, but still provided an accessible method that could be
adapted to all the tree species found and showed physiological
relationships between DBH, tree volume and wood density.
Bunce (1968) found that the growth of species altered according to
site conditions, so transects and multiple woodlands would allow
discovery of the different physical characteristics of specimens
potentially planted at the same time. To calculate the
characteristics, basic formula and coefficients were used for each
species. A number of different formulas were available for each
species (Jenkins 2003) but some equations excluded the tree stump
and others avoided the root system. The method generalises
characteristics but makes a full estimate of the tree carbon, rather
than only some of the tree as was seen by other equations ( Jenkins
et al, 2003) . This use of the same basic formu lae was
47
recommended, allowing use by a wider range of those involved in
carbon sequestration in the future (Pastor et al (1994), Jenkins et al
(2003).
A full list of coefficients used is found in Appendix 3
The carbon content of trees was assumed to be 50% of the biomass
(Crack 2002, Hutyu et al 2011, Jo 2002) and the rooting systems
were assumed to by an additional 25% of the aboveground biomass
(Jo and Mcpherson 1995, Novak and Crane 2002)
Formula for biomass calculations taken from Clark
et al (1986)
E q u a t i o n 1 : A G V = C1((D2 )C 2)H
AGV= Above Ground Volume of tree
C1= Coefficient of wood storage in trunk and stems , based on
species of tree
C2= Coefficient based upon age of tree; younger trees store at a
faster rate than older trees
D= Diameter in Inches of tree
Equation 2: TV= AGV*1.25
TV= Total Volume, including the rooting system
Equation 3: DB= TV* C3
DB= Dry Biomass
C3= Coefficient linked to species storage of wood
Equation 4: TC= DB*0.5
TC=lbs of carbon sequestered in tree.
4.2.4 Trial sample
This initial investigation enabled a determination in the difference
of each area in terms of composition of ages and species. Transects
48
of
5x10,
10x10,
20x20,
10x30
30x30m2
and
were
undertaken,
concluding that a 10x30 transect allowed the best balance between
representation of the trees in the area and time efficiency. The
transect size was larger than some recommended due to the high
variations found within these small woodlands from the edges to
the centre and this sample gave good representation of the area.
4.3Measurement validity + reliability
The
basic
physical
measurements
of
the
DBH
and
height
were
representation of the composition of the area. Modeling of these
values
as
to
the
carbon
stored
was
an
interpretation
of
the
measurements using coefficients, which although the suitable found
for this method, were based upon American species and climates.
Tree age was calculated by examining the width of the trunk and
assumptions were made that trees grow at a steady rate according
to their species, and according to the density of the woodland
(Jenkins 2003), a formula is found in Appendix 3.
Data collection
o
Visual
taken
identification
from
of
height
was
undertaken
with
advice
(http://www.rfs.org.uk/learning/measuring -
trees#volume) but there was a problem with the initial method
using trigonometry, due to sloping ground and the close canopy of
some areas of woodland.
Despite the problems encountered the
results are thought to representative of the heights of the trees.
This
method
had
to
be
subjective
but
was
done
by
the
same
individual, reducing errors between sampling. A visual assessment
was carried out
as to whether the tree
was s in a densely or
sparsely planted area by examining if the trunks were more than
two feet apart (Nowak and Crane, 2002). If a tree had two trunks,
it was examined as two trees due to the method of measuring the
physical volume of the trees.
Data analysis
Calculations were entered into the model and used to calculate
carbon content, by estimating dry matter from total volume using
49
coefficients (E.g. Oaks have around 27% water content, Birches
31% and willows 41%). This enabled comparisons of the hardwood
and
softwood
content
of
trees
and
different
growth
patterns
according to the age of the tree. Adapting for climate meant the
figures
should
have
been
altered
although
by
how
much
was
indeterminable and therefore not carried out.
Older stands have been shown to store less carbon than younger
trees and 25- 125 year old trees will store significantly different
proportions of carbon and so rates of storage were calculated based
upon estimated age of the trees (Coome et al 2012).
Future growth was calculated for each area over 1, 5, and 10.
Older stands were estimated to contribute little in future growth,
whilst young saplings of around 15 years contributed the largest
increases. Managed thinning in identified areas such as Sycamores
and Abbas Gardens was accounted for. This is expected to occur
over the next 5 years, and growth w ill have begun to recovered in
10 years. Death rates and animal activity would still have an effect
of reducing overall carbon storage but was not quantifiable. It was
minimised in idealised management situation and taken as similar
values to the present in the no change scenario . Events such as
disease and storms are a distinct possibility in the next 10-20 years
and would have devastating effect, as a number of trees were based
on thin soils and slopes, but in the next twenty years, the number
and extent of these events is so uncertain that it has not been
accounted
for.
This
is
a
decision
that
may
make
the
modeled
carbon stored artificially high, but without knowing how much to
reduce it by, this remains.
Soil Sam pling Materials and Methods
Study area
The soil samples sampled a range of different soil types and land
uses
on
the
farm
including;
orchard,
arable,
woodland
and
grassland.
50
Sampling Design and Data collection
Selected sample sites were used, as the study wanted to ensure a
range of samples was taken in the time frame allowed. As samples
were taken at Leckford and had to be transported back to UEA,
Norwich for storage and analysis, this greatly limited the number
available to be taken. Because of this, grass areas between the
orchards and set aside at the sides of fields were not taken and
take a particular focus; the effect of woodland management on
soils and the effect of tilling practices . These grass areas would be
important for an overall understanding of the relationship between
the arable land and grass land and assist in explain ing their role in
soil carbon storage compared to natural areas such as the peatland.
This was focused to ensure sampling could take place over 1 day
and
degradation
Further
of
previous
restrictions
were
samples
in
the
taken
peaty
would
areas
su ch
not
as
occur.
Charity
Meadow and Water Garden, as Charity Meadow site is designated
as a SSSI (Site of Special Scientific Interest) and the Water Garden
management
team
were
keen
to
avoid
disruption
to
rooting
systems.
Allowing
the
sample
to
be
representative
of
a
wider
area
was
advised (Hodgson 1978) and is encouraged for future, more focused
study. But the samples obtained would give a greater impression as
to the affects of wider spread soil and climate effects, rather than
the smaller effects of interfield mixing.
A
transect
sample
was
take
from
woodlands
through
to
arable
fields next to them at the ‘Vicars Cross’ and ‘White Gate and
Owens Wood’ sites, to determine the effects of land use across a
short distance on the same type of underlying soil
The vineyard site was sampled, having experienced a change of
land use from arable in 2009 and would examine the relationship
between the two land types. No arable sites experienced radical
land use change in the last 20 years due to the site examining longterm
outputs
from
these
areas.
Therefore,
despite
the
soil
composition changing uniformly across the site due to implemented
51
use of fertilisers and then increased use of manure, the topsoil will
represent
the
most
examined
separately
recent
to
processes
see
the
and
the
historic
subsoil
legacy
of
will
be
previous
practices.
Sampling methods
As many soils were dry and had granular structures , soil cores
could not be taken
from
most
sites.
Subjectively
samples were
taken from representational parts of soil, the center of the area if
possible to reduce effects from mixing at the side and different
composition
of
the
woodlands
at
the
edges.
Any
detritus
was
identified and samples were taken. Topsoil extraction was sampled
by visual assessments as to where the horizons met, as there is not
a standard depth between the two horizons and it is often distinct.
Subsoils were selected after a visible change in colour/texture was
identified. This was around 10-12 inches deep in agricultural areas
and shallower (3-4 inches) in woodlands due to the comparative
lack of mixing. The chalky fragments made it difficult to sample to
the required depth in some of the arable and orchard fields .
Not being able to sample destructively as Leckford is a working
farm and avoiding affecting biodiversity of the woodlands led to a
small core being extracted of 5 inches wide and as deep as required
by the subsoil strata, rather than a sampling pit of 1m x 1m x 1m
which would allow full extraction of samples and clarification of
the layers present. Visual analysis of soil was undertaken as to
colour, texture and structure ( Reeuwijk, 2002)
Data collection and procedures
Samples were stored in cling film to minimise moisture loss during
transportation. A 10-20 g of sample was sieved so particles of
0.2cm remained as many large chalk fragments were present this
ensured representative results and prevented distortion of results
by
large
mineral
deposits.
Scales
were
accurate
to
0.01gThe
samples were heated in an oven for 15 hours at 105degrees after
52
being checked to ensure all were completely dry (Konare 2010).
Samples were then incinerated in a furnace at 450 degrees for 10
hours to ensure all organic matter was burnt
Equation 1: MC (% weight) = ((B -C)/(C-A))*100
Equation 2: LOI (% Dry Weight)= ((C-D)/(C-A))*100
A=Weight of crucible
B=Weight of crucible+soil
C=Weight of crucible +soil
D=Weight of crucible + soil LOI
LOI= Loss On Ignition
MC=Moisture Content
Data Analysis

The results were analysed for carbon content and differences
between land uses and top and sub soils.

Calculated Ctha-1 by using the protocol as set out by (Reeuwijk,
2002)
53
5. Results
5.1 Woodla nd Results
Appendix 6 is a copy of the physical data collected for trees in the
Parkland area. It demonstrates the data collected for an area 625m2
and in comparison to the Water Garden b) sample (Appendix 7,
area 300m2) it is clear as to the vast differences in physical data
collected.
Dbh and height of trees in Vicars Cross
Diamter at Breast Height (cm)
250
200
R² = 0.9548
150
100
50
0
0
20
40
60
Height (feet)
80
100
120
Figure 5.1 Height and DBH of trees sampled at ‘Vicars Cross’
54
Diameter at Breast Height (DBH)
DBH and height of trees in Water
Garden b)
200.00
R² = 0.8664
160.00
120.00
80.00
40.00
-
20.00
40.00
60.00
Height (feet)
80.00
100.00
Figure 5.2: Height and DBH of trees sampled at ‘Water Garden b)
Figures 5.1 and 5.2 demonstrate the difference in composition
between just two sites as to the height and DBH. Figure 5.2 shows
a spread of mostly young saplin gs and trees becoming thicker as
they age proportionally more than they gain height. Figure 5.1
shows far fewer trees present in the sample, and a split between
young sapling and mature, thicker trees.
55
Water Garden b) unmanaged woodland
Proportion of Carbon Dioxide
stored by each wooded area
Parkland
Nursery Wood
Riches Plantation
Water Garden a) Managed garden
Wood Next to Vineyard
Abbas a) managed garden
Dairy Processing Woodland a) newly planted area
Verlynch
Strattons Wood
Money Bunt Wood
Top Plantings
Oil Well Forest b) Mixed
Bowshers Wood
Owens Wood and White Gate Wood
Sycamores
Lone Barn Wood
Abbas b) unmanaged woodland
Little Plantings
Chilcombe Wood
Vicars Cross
Charity Wood
Somertons Wood
Octagonal Wood
Willow Wood In Chicken Enclosure
Dairy Processing Woodland b) established area
Plantation Next To Octagonal Wood
Oil Well Forest a) Deciduous
Figure 5.3: A diagram illustrating the numerous woodland sites
present on Leckford Estate and the role each plays in carbon
storage.
Figure 5.3 illustrates that there are two areas contributing just
over a third (37.9%) of the total carbon storage of the site. This is
due primarily to their size and consisting of predominantly mature
woodland. As shown by 5.4, thi s trend will continue for the next
ten years, but storage in other areas such as Bowshers wood and
Water Garden b) are predicted to increase, increasing the
contribution. All areas were predicted to increase in carbon
storage, except Oil Well Forest b) as the coniferous trees present
to act as shelter for the developing beech trees will die and
56
expected to remove 7% of the carbon store. But as seen in
Bowshers wood, which has lost most of its coniferous stands, the
rate of potential increase is large as new saplings quickly store
more carbon. This is reflected in rapid sequestration rates in the
Plantation next to Octagonal Wood and Dairy Processing
Woodland b) as the clearings in the Plantation allow growth of new
trees and the planted saplings in the Dairy Processing Woodland b)
establish quickly and begin sequestering.
Areas with pre-existing large sequestrations of carbon are not
expected to increase carbon storage very much with the Parkland
and Verlynch sites both expected to increase their carbon stor age
by 3%. The greatest proportional increases were seen in the
‘Oilwell forest b) Mixed’ and ‘Dairy Processing Wood b)’ (178%
and 115% respectively) due to the rate of growth seen by saplings.
Tonnes of carbon stored /ha
Modelled sequestration of carbon storage
/ha
250.00
200.00
150.00
100.00
50.00
0 year
0.00
1 Year
5 year
10 year
Area of woodland
Figure 5.4 Modeled expectations from the present for 1, 5 and 10-year
projections dependent upon current physical characteristics of site.
57
0%
Orchard 5 Sub
Orchard 5 Top
Orchard 16 Sub
Orchard 3 Sub
Vineyard Sub
Arable C13/C14 Sub
Orchard 15 Sub
Vineyard Top
Riches Plantation Top
Arable Next to Orchard 5 Sub
White Gate Wood Sub
Orchard 3 Top
Orchard 16 Top
Arable Next to Vicars cross Sub
Orchard 15 Top
Oilwell Deciduous Woodland Sub
Dairy processing, Young woodland Sub
Arable C13/C14 Top
Arable Next to Vicars cross Top
Watergarden Sub
Arable on Clay (C3B2) Sub
Oilwell Mixed Woodland Sub
Arable on Clay (C3B2) Top
Oilwell Deciduous Woodland Top
Arable Next to Orchard 5 Top
White Gate Wood Top
Vicars Cross Sub
Riches Plantation Sub
Watergarden Top
Charity Meadow Sub
Vicars Cross Top
Dairy processing, Young woodland Top
Charity Meadow Top
Nursery Wood Sub
Oilwell Mixed Woodland Top
Nursery Wood Top
Lone Barn Wood Top
Lone Barn Wood Sub
5.2 Soil Results
Soil compositions ranked by organic matter
content
% Mineral content
Water content (%)
Organic matter (%)
100%
80%
60%
40%
20%
Figure 5.5: Graph of soil compositions by % weight of water,
mineral and organic matter content.
58
tCha and SOM% in Subsoil
Tonnes of carbon per heactore
350
R² = 0.8812
300
250
200
150
100
50
0
0.00
5.00
10.00
15.00
20.00
Soil Organic Matter %
25.00
30.00
Figure 5.6: Subsoil tCha-1 and SOM%, showing a direct positive
correlation in deeper soils.
Tonnes of Carbon per heactare
tCha and SOM% Topsoil
300
250
R² = 0.5137
200
150
100
50
0
0.00
5.00
10.00
15.00
Soil Organic Matter %
20.00
25.00
Figure 5.7 Topsoil tCha-1 and SOM% showing a polynomial
relationship, with lowest and highest tCha -1 showing different
relationships with SOM%
Figures 5.7 and 5.6 show clear differences in the practices taking
place on topsoils and subsoils. Subsoils are well-settled and
accumulated high levels of SOM and thereby tCha -1 follow at an
expected rate as compaction is more uniform. Topsoils, suffer
different compaction levels, plant matter inputs and mixing with
the external air.
59
Topsoil and Subsoil percentage volumes of soil
samples
30
25
20
15
10
Lone Barn Wood
Nursery Wood
Oilwell Mixed…
Charity Meadow
Dairy processing,…
Vicars Cross
Watergarden
White Gate Wood
Arable Next to…
Oilwell Deciduous…
Arable on Clay…
Arable Next to…
Arable C13/C14
Orchard 15
Orchard 16
Orchard 3
Subsoil Organic matter (%)
Riches Plantation
0
Vineyard
Topsoil Organic matter (%)
Orchard 5
5
Figure 5.8: The differences between topsoil SOM and subsoil SOM.
Subsoils are shown to contain less SOM in most soils but mature
woodlands and arable fields based on clay. In the dense woodlands,
soil has been accumulating over many years and the clay particles
in the arable field provide excellent protection.
50.00
Average Organic and Water contents of
soils by land use
40.00
30.00
20.00
10.00
0.00
Arable
Orchard
Average organic content
Coniferous
Broadleaf
woodland
Average water Content
Mixed
Broadleaf and
Coniferous
woodland
Grassland
Figure 5.9. Average Organic and Water contents of differen t land use
categories by Leckford Estate,
60
Figure 5.9 shows the expected general positive relationship
between water content and organic matter. Woodlands contain
more water content as the forest floors are shaded and contain
detritus material as a cover and the peaty grasslands were
waterlogged and had high initial water tables.
tCha for top soils and subsoils of different
land uses
Coniferous
Peat Grassland
Broadleaf
Mixed B and D
Arable on Clay
Arable
Orchard
Gleyed Soil
0
50
100
Topsoil Tcha
150
200
250
300
350
Subsoil tCha
Figure 5.10 The Topsoil and Subsoil Carbon storage values for
different land use categories on Leckford Estate. Error bars were
calculated using 1 S.E.D.
The above figure (5.10) shows the differences in tCha -1 stored
within each land use on the site. As the gleyed (waterlogged)
grassland soils contained much water, their bulk density was very
low and so was to proportion of carbon held. Orchard soils
contained lower levels than arable soils, due to lower inputs of
61
manure and fertiliser, arable crops provide a cover for the soil
whilst growing and can reduce temperature and moisture changes.
Predominantly coniferous woodlands such as Lone Barn Wood and
Vicars Cross were shown to have the greatest carbon storage, and
other woodlands were also high.
Discussion
Analysis of results
Woodlands
Some sites were large and diverse enough to be split into two
different areas of woodland , which would be assessed separately.
These
areas
have
been
kept
separate
for
the
consideration
of
carbon that they store, as the recommended management plans for
each area would also be different.
The figures for the model are generally similar to those thought to
be
produced
by
woodland
areas
(Chapman,
2009).
This
demonstrates the accuracy of the method, although the figures for
each area differ slightly due to their physical nature. The figures
are subject to change due to different coefficients available and
predictions for survival rates of the trees, but are accurate enough
to establish tailored management plans for each area.
Carbon sequestered per area
The largest areas were found to store most carbon, but some more
efficiently
than
others.
As
shown
by
figure
5.3
two
areas
contribute more than 37% of the total storage, but the Parkland is
largest area and contributes proportionally less. This shows great
differences in efficiency between areas, which cannot be tackled in
areas such as the Parkland and Water Garden as their aesthetic
value is so great to the Estate. The current amounts sequestered
each year are comparable with figures found for the UK in the
62
literature
but
with
application
of
the
model,
these
changed
according to the current stages of development of t rees, with areas
with
young
carbon
saplings
storage
each
expected
year
and
to
experience
more
mature
larger
areas
increases
of
in
woodland
reaching carbon storage saturation level .
IMAGE A: Oilwell Forest (b); Mixed woodland.
IMAGE B: Oilwell Forest (a); young broadleaved woodland
The difference between the two images above was clearly reflected
in the model reflecting the physical differences in the size and
measurements of the trees. The difference in undergrowth was also
noted and is discussed in the soil results analysis.
63
IMAGE C: Water Garden (a).
Differences between the two nearby parts of the water garden were
clearly shown by the model, but the effect of density and grass
management were particularly prominent here.
IMAGE D: Bowshers wood.
Image D had been planted in a similar fashion to Image A but is
more mature, shown by the large amounts of deadwood on the
forest floor, radically reduced numbers of conifers and increased
light penetration through the canopy.
Bowshers
wood
and
the
Oilwell
Mixed
wood
(a)
are
both
at
different stages of the same planting scheme. The Oilwell Mixed
wood
currently
contained
more
carbon
stored
in
trees,
but
64
Bowshers wood has more potential for younger trees as clearings
have
been
created,
reflected
in
the
10-year
model
forecast
for
carbon storage.
Soils
The underlying bedrock of the site is predominantly chalk and
there are particularly shallow soils in some of the arable areas
making it difficult to calculate the full carbon potential of the site.
The condition of the soil was used in conjunction with estimates to
produce a figure for the current carbon storage of the site. This
was held against the potential for the increasing in organic matter,
and therefore carbon content, of the soil by careful management
practices.
The
soils
were
collected
after
6
days
without
rain
under
fair
sunshine, so water content of topsoil was lower than expected,
although this should not have affected the organic matter content
nor the water content of the sub soil. Only one sample was taken
per site due to time constraints and the distance that would have to
be travelled to collect more samples.
The soils had values at the bottom end of the C-storage averages
predicted for the UK, and this may be due to the comparatively
high
rainfall
and
low
sunshine
the
area
receives.
Only
the
coniferous areas showed high current storage, but all areas showed
much potential with the use of mulches on agricultural soils.
65
Top Soil and Sub Soil
Image E: Topsoil (L) and subsoil (R) of the Oil Well Mixed woodland.
Image E Shows how the leaf litter from the forest has caused large
build ups of humic acids reflected in the darker appearance of the soil.
As expected, there was a difference in Soil Organic Content (SOC)
and water content between top- and sub- soils. The average water
content was highest in the sub soils, as water is leeched down into
the
deeper,
covered
soil
and
much
of
the
remaining
water
in
surface soils is evaporated or absorbed by plant life . The highest
average soil organic content was found in the surface soil s, which
is due to the addition of manure and fertilisers to the soil. There
were high levels of manure found in the clay soils near White Gate
and Owens woods, which added to the structural integrity of the
soil and allow for more nutrients and water to b e stored amongst
the minerals.
66
Detritus
Image F: Detritus samples from Oil Well Forest b) (L) and Lone Barn
Wood (R)
Some
areas
benefits
providing
had
the
significant
soil
the
in
soil
many
with
detritus
ways.
shade,
covering
One
of
reducing
the
these
the
floor,
is
which
continually
potential
for
evapotranspiration. In the woodlands where there was little grow th
on the forest floor, due to a thick canopy reducing ground light
levels, there was much detritus found as leaf litter accumulate d.
This provides a barrier against oxidation of the soil and removal of
water, allowing rich soils to develop with high organic soil carbon
contents.
Image G: Showing Topsoil (L) being particularly hard and of poor
quality. Difficult for roots to break through.
67
Image H: The soil core taken from Charity Meadow.
Land use and how it affects SOM content.
Land use strongly influences carbon content of soil, with arable
and
orchard
woodland
soils
and
showing
grassland
soils
significantly
(P
value
different
<0.01).
values
This
was
to
in
accordance with expected values (Hester and Harrison 2010, Fitton
et
al
2011)
and
confirms
that
the
repeated
tilling
of
soil
and
intensive use of the land is reducing available soil carbon. Orchard
soil carbon levels were slight ly higher than arable soils, indicating
grass strips between rows of trees provides useful soil cover and
aids in SOM storage. “Set-aside” around the edges of fields also
yielded higher carbon values.
68
Image I: Comparison of soil samples. (L) Arable soil next to Vicars
Cross (Top) with Water Garden (BOTTOM). (R) Vicars Cross Woodland
soil (Top) with soil from the arable field adjacent to it (Bottom)
Image J: Soil samples taken from Leckford Estate as they were
extracted from the soil.
69
Image K: Soil samples from Leckford Estate after removal of water
content
Image L: Soil samples from Leckford Estate after removal of organic
content.
The last three images show clear changes in the appearance of the soil
as is initially dried and organic matter is burned off, leaving some soils
a pale grey and some high clay content soils a dark red.
70
Analysis of investigation methods
Firstly, the results obtained from the investigation regarding the
carbon stored in each area of woodland have produced rad ically
different figures after a detailed investigation. This investigation
of the individual trees allowed each area to be considered in detail
according to
its size and current health and development. The
model also allowed for areas as different as the parkland and the
willow crop in amongst the chicken farm to be considered on their
own merits as the density, average size and age of the trees were so
very different. A blanket model if used online would have produced
figures
of
around
245
tonnes
of
carbon
per
year
for
the
site,
compared to the 224 tonnes obtained by the model used in this
study. This figure was generated by the “CALM” calculator, and
measure coniferous or broadleaved woodlands based around thr ee
age brackets: 0-10 years old, 10-20 years old and older than 20
years. This did not allow for the density, health or composition of
the woodland to be considered. This model considers a hectare of
the Parkland, with a density of just 4 trees for every 3 00m sample
site and a carbon storage of 0.56tCha-1 in 2012, the same as the
much denser and less heavily managed area of the Sycamore, which
had a carbon storage of 4.45tCha-1. It did, however, allow for
measurements of management under the HLS program, which have
been used as the basis for changes in future modeling to prevent
approximation
of
figures
according
to
American
models.
The
CALM calculator over-estimated the volume of carbon available
due to the inability of understand the mix of trees.
As this investigation’s figures were so different and reflected the
true
state
of
the
woodlands
in
each
area
rather
than
just
representing an average value, these figures give more value when
analyzing strategies.
The model used was limited as it could not use the ages of trees,
but it can however compare what carbon already exists in the area
of forest to how much is being stored each year . It was extremely
71
difficult to fit the data to a pre-made model, thus much literature
was consulted to produce as accurate figures as possible to fit the
available data. This remains an evolving field so further studies
are
encouraged
on
the
carbon
sequestration
of
the
woodlands
currently in place on Leckford, once ages of the trees become more
accurately determined. This is as the more accurate figures that
will inevitably come perhaps even tailor-made to the local climate,
can be inserted and referenced against this previous model. Many
of
the
available
figures
are
aimed
at
growth
rates
based
in
America, and in many of the wo oded sites on the Estate, the exact
age of the trees was unknown.
Limitations
There were a number of limitations associated with this study due
to
its
nature
interpretation,
differences
and
as
an
but
can
evolving
the
be
basic
field.
data
inputted
into
Models
shows
leave
great
future
much
for
physiological
models
for
further
comparison.. It is difficult to predict deaths and unexpected severe
weather events can restrict growth for decades as old stands are
reduced and new growth will take time to establish ( Coomes et al,
2012).
Coomes also estimates that increases in severe weather events will
increase the number of old stands falling, seen on the Es tate after
a number of severe storms occurring in 1987 and 1990. According
to
the
Woodland
Management
plan
some
significant
felling
occurred and replanting had taken place (2012).
There was no method found to allow farmers to access a simple,
straightforward
model
by
which
exact
measurements
could
be
gained. Generalisations for co-efficients to gain a general picture
of carbon volume storage are potential options, and these figures,
whilst
not
completely
accurate,
can
give
an
impression
of
the
general storage of each area.
72
This investigation has not found a simple, or even an completely
accurate measurement but shows areas for further research due to
the positive findings.
Recommendations for future research a nd ongoing
proj ects
Most of the aims and objectives were met of the investigation. The
orchards were not considered woodland as they were on a 25 year
cycle and will be relatively inert in terms of carbon storage cycle.
Due to the short time frame this was not pursued, by the orchards
can be addressed using the calculations available as the age of
these sites is well documented. The w illow storage was examined
as a comparison of a quick growing tree, although it has known
negative influences on water tables. Hedgerows will certainly be a
significant
mid
to
long-term
storage
of
carbon,
and
are
recommended for investigation.
In accordance with management plans produced for the farm in
2008, priorities have been for the promotion of biodiversity due to
a number of rare species (predominantly birds) found on the site.
This
aim
Stewardship
is
combined
agreement
with
(HLS)
a
with
Higher
Level
Natural
Environmental
England
to
remove
alien species such as Sycamore and invasive Willow. This will
allow
thinning
of
the
woodlands
and
natural
resurgence
of
undergrowth and young saplings, although it will take a number of
years before the initial carbon hel d in the area is replaced.
This is a major difficulty in aiming to store large amounts of
carbon in an area, as the most efficient ways of storing large
volumes of carbon would be by planting a rapidly growing species
such as Sitka Spruce, which can sequester around 10tCha-1yr-1 for
a period of about 30 years (Murray, 1995). It would however have
major effects on the soil carbon and biodiversity of the area and
these balances need to be assessed. For this type of farm, the
continuation of promoting native species is encouraged to produce
73
large
long-term
storage,
if
at
slower
rates
as
the
social
and
landscape benefits would assist in the success of the scheme.
7. Conclusion
In conclusion, this project highlights the need for careful analysis
of individual woodlands at a local scale in the UK due to the
significant difference in results and physical composition for each
area
examined.
The
differences
between
each
site
have
been
identified and shown to contribute largely towards their varied
carbon storage levels year on year. As these areas differ so greatly,
individual management plans to not only enhances carbon storage,
but
also
healthy
enhance
the
ecosystem
is
ecology
likely
to
and
biodiversity
store
more
are
carbon,
vital,
due
to
as
a
the
increased biomass it can support.
The different conditions of the soil across the site show typical
degradation
of
SOC
deprivation
of
the
due
soil
to
of
agricultural
regeneration
practices
periods
and
the
necessary .
Compared to average agricultural soils the values were higher in
the topsoils than expected in the subsoil, due to the lower intensity
of tilling practices and having much manure adage creating higher
volumes of organic input raising the base level of SOM.
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Appendix
Appendix 1
GIS map of Leckford Estate
80
Appendix 2
MasterMap and OS Data of Trees sites sampled on Leckford Estate ,
using landuses designated by MasterMap.
Appendix 3
MasterMap and OS Data of Soil sites samples on Leckford Estate.
81
Appendix 4
Clark’s (1986) Coefficients Used and Tree age Formulas
Coefficients
Species
Ash
Other Hardwood
Beech
Birch,
Cedar, Red
Cherry, Black
Cherry, white
Equations
m=.1063 dbh
2.4798
m=.0617 dbh
2.5328
m=.0842 dbh
2.5715
m=.0629 dbh
2.6606
m=.1019 dbh
2.3000
m=.0716 dbh
2.6174
m=.1556 dbh
2.1948
82
m=.0792 dbh
2.6349
m=.0622 dbh
2.4500
m=.0629 dbh
2.6606
m=.0792 dbh
2.6349
m=.0554 dbh
2.7276
m=.0579 dbh
2.6887
m=.1617=dbh
2.1420
m=.0910 dbh
2.5080
Flowering dogwood and Hawthorn
Yew
Elm, American
Hornbeam
Oak, chestnut
Oak, white
Other Coniferous
Maple, Red
Tree age formula,
Tree age= DBH(cm)/ average growth rate.
Average trunk growth rates used (girth) per year (cms) Clark (1986)
Softwoods- 2.5
H ardwoods-1.5
Pine -7
Other conifers-1
Yew 0.7
Appendix 5
Physical data collected from the Parkland sample site.
Subdivision Name
Prunus
Avium Plena
A
(Cherry)
Scots Pine
Prunus
Avium Plena
(Cherry)
Japanese
Maple
Tree Type
Tree
Height
Dense
forest?
Width
(cm) at
150cm
high
H
32
N
125
C
35
N
174
H
37
N
174
H
7
N
12
83
Eucalyptus
Japanese
Maple
Japanese
Maple
Japanese
Maple
H
48
N
406
H
10
N
26
H
25
N
51
H
12
N
38
Appendix 6
Physical data collected from the Water Garden ) site
Subdivision
B)
Dense
forest?
Y
Y
Y
Y
Y
Y
Width
(cm) at
150cm
high
7.00
17.00
116.00
3.00
8.00
131.00
Name
Rowan
Sycamore
Alder
Rowan
Sycamore
Rowan
Tree Type
H
H
H
H
H
H
Tree
Height
9.00
20.00
55.00
9.00
15.00
90.00
Flowering Dogwood
Rowan
Alder
Rowan
Rowan
H
H
H
H
H
20.00
14.00
23.00
10.00
16.00
Y
Y
Y
Y
Y
16.00
7.00
35.00
5.00
8.00
Coppiced Alder (6 trunks)
Sycamore
Hawthorn
Sycamore
H
H
H
H
60.00
26.00
12.00
7.00
Y
Y
Y
Y
94.00
18.00
8.00
7.00
Sycamore
H
16.00
Y
11.00
Coppiced Sycamore
H
23.00
Y
19.00
Coppiced Sycamore
Hawthorn
Rowan
H
H
H
10.00
12.00
5.00
Y
Y
Y
6.00
11.00
6.00
84
Alder
Sycamore
Alder
Sycamore
Alder
Sycamore
Sycamore
Hawthorn
Sycamore
Rowan
Sycamore
Alder
Coppiced Sycamore 2
shoots
Sycamore
Sycamore
Sycamore
Sycamore
Rowan
Hawthorn
Hawthorn
Beech
Sycamore
Sycamore
Hawthorn
Alder
Sycamore
Sycamore
Alder
Coppiced Beech 8 Shoots
Alder
Sycamore
Sycamore
Sycamore
Alder
Hawthorn
Rowan
Hawthorn
Sycamore
Holly
Dogwood
Sycamore
Hawthorn
Hawthorn
Hawthorn
Hawthorn
H
H
H
H
H
H
H
H
H
H
H
H
40.00
28.00
28.00
28.00
40.00
16.00
15.00
15.00
10.00
11.00
28.00
38.00
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
74.00
28.00
102.00
30.00
83.00
13.00
12.00
18.00
10.00
3.00
15.00
87.00
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
30.00
10.00
8.00
29.00
29.00
80.00
12.00
8.00
30.00
20.00
31.00
25.00
50.00
33.00
16.00
45.00
18.00
45.00
24.00
15.00
20.00
40.00
8.00
50.00
7.00
25.00
4.00
20.00
30.00
8.00
10.00
15.00
7.00
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
20.00
12.00
7.00
20.00
22.00
191.00
8.20
5.00
31.00
25.00
30.00
30.00
90.00
24.00
15.00
80.00
18.00
120.00
24.00
12.00
16.00
104.00
6.00
94.00
4.00
23.00
2.50
20.00
26.00
2.50
5.00
11.00
1.00
85
Hawthorn
Sycamore
Hawthorn
Alder
Rowan
Alder
Hawthorn
Sycamore
Sycamore
Sycamore
Sycamore
Sycamore
Hawthorn
Sycamore
Rowan
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
12.00
13.00
12.00
30.00
70.00
40.00
8.00
10.00
8.00
15.00
25.00
30.00
4.00
18.00
30.00
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
7.00
10.00
12.00
90.00
168.00
70.00
5.00
7.00
4.00
10.00
18.00
27.00
2.00
10.00
35.00
Appendix 7
A summary of the soil calculations, full data set on request from
[email protected]
Location
Land Use
Topsoil/
Subsoil/
Organic
matter (%)
tCha
Water content
(%)
Arable Next to
Orchard 5
Arable
Top
10.91
160
15.87
Arable Next to
Vicars cross
Arable
Top
9.47
149
9.64
C13/C14?
Arable
Top
9.36
155
4.59
Arable on Clay
(C3B2)
Arable On clay
Top
10.03
161
7.69
Lone Barn Wood
Coniferous
Top
19.53
258
24.06
Vicars Cross
Coniferous
Top
13.41
192
17.76
Watergarden
Gleyed soil
Top
12.57
47
78.56
Oilwell Mixed
Woodland
Mixed B +D
Woodland
Top
16.62
198
31.56
86
White Gate Wood
Mixed B +D
Woodland
Top
11.64
159
21.65
Oilwell Deciduous
Woodland
Mixed Broadleaf
Woodland
Top
10.26
149
16.70
Dairy processing,
Young woodland
Mixed Broadleaf
Woodland
Top
13.92
218
9.83
Riches Plantation
Mixed Broadleaf
Woodland
Top
7.29
105
17.51
Nursery Garden
Mixed Broadleaf
Woodland
Top
17.07
144
51.54
Orchard 5
Orchard
Top
4.76
74
10.87
Orchard 15
Orchard
Top
9.18
144
9.94
Vineyard
Orchard
Top
6.71
111
4.97
Orchard 16
Orchard
Top
8.08
133
5.35
Orchard 3
Orchard
Top
7.75
128
5.02
Charity Meadow
Peat Grassland
Top
14.10
128
48.04
Appendix 8.
A summary of the forest calculations and models. Full data set on
request, as above.
Woodland
name
Water
Garden a)
Managed
garden
Water
Garden b)
unmanaged
woodland
Density
of trees
in
300m
12
80
Area of
woodland
(m2)
Total
Carbon
(Tonne
s)
stored
in area/
annum
32,623.51
7.58
112,046.91
61.38
Estimated
storage using
CALM
calculator
values
9.70
33.30
Current
area
storage
Area
Area
storage storage
in 10
in 10
years:
years:
with
current
manag practices
ement
578.22 605.29
605.29
2,227.91
2,504.71
2,582.1
7
87
Nursery
Wood
16
Parkland
4
Vicars Cross
Verlynch
Little
Plantings
Sycamores
Money Bunt
Wood
Chilcombe
Wood
Lone Barn
Wood
Top Plantings
Plantation
Next To
Octagonal
Wood
Octagonal
Wood
Riches
Plantation
Abbas a)
managed
garden
Abbas b)
unmanaged
woodland
Willow Wood
In Chicken
Enclosure
Charity Wood
Owens Wood
and White
Gate Wood
Wood Next to
Vineyard
Oil Well
Forest a)
Deciduous
Oil Well
68,932.49
19.27
20.49
1,015.72
1,062.85
1,084.5
4
166,205.92
15.40
49.40
1,793.82
1,848.82
42
23
19
8,949.74
15,519.77
13,931.11
3.67
7.69
2.61
2.66
4.61
4.14
134.92
338.18
175.17
1,848.8
2
148.01
349.31
184.50
42
31
6,415.93
22,073.85
3.99
7.67
1.91
6.56
206.93
290.18
208.36
317.57
208.57
317.57
23
19,029.29
2.54
5.66
152.43
188.75
188.75
33
12,155.54
5.40
3.61
196.66
206.30
206.30
24
38
18,588.52
4,915.23
5.33
1.08
5.52
1.46
276.52
19.19
295.56
36.56
295.56
32.90
45
10,670.75
2.11
3.17
67.45
74.98
74.98
59
28,606.70
11.31
8.50
621.08
653.39
594.59
7
20,192.60
4.50
6.00
409.20
414.15
414.15
72
20,286.37
8.91
6.03
189.09
220.91
220.69
271
33,697.41
4.83
10.01
44.39
61.64
55.47
42
34
11,057.65
23,160.92
4.04
6.47
3.29
6.88
107.15
210.43
121.57
233.55
108.20
221.87
27
19,223.91
6.87
5.71
423.52
425.65
421.39
145.05
349.66
184.50
37
10,469.00
0.53
3.11
18.58
39.96
37.56
35
15,469.00
7.68
4.60
247.90
230.24
225.64
88
Forest b)
Mixed
Bowshers
Wood
Dairy
Processing
Woodland a)
newly
planted area
Dairy
Processing
Woodland b)
established
area
Somertons
Wood
Strattons
Wood
46
21,139.97
11.03
6.28
213.26
252.65
257.70
49
58,586.76
4.55
17.41
345.07
484.98
421.94
20
14,822.13
1.56
4.41
37.03
54.10
51.94
38
8,419.75
1.84
2.50
102.36
108.93
108.82
20
16,859.15
4.83
5.01
292.84
310.09
308.54
Total
224.68
241.93
11,474.01
10,735.1
7
11,742.
54
89