CARBON SEQUESTRATION IN LANDSCAPES With reference to Carbon Auditing for the Landscape Industry.

Howard Wood B.Sc.(Hons.)

Landscape & Environmental Services Ltd.

The Carbon Cycle Plant respiration

Animal respiration

Factory and automobile emissions

CH4 Organic decomposition

Fossilisation

Root respiration

Oceanic absorption Sedimentation

UNDERSTANDING CARBON – A FEW FACTS • Conventionally Green House Gases are expressed as CO2 equivalent. • Man’s activity contributes to an annual increase of 6 500 000 000 tonnes of CO2 / yr. of which about half is reabsorbed by increased photosynthesis and by dissolution in the oceans. • A European citizen emits 16 t CO2 per year. • Methane is CH4 is 21 times more effective as a greenhouse gas than CO2.

• Nitrous oxide (N2O) produced in fertiliser manufacture is 300 times more effective as a greenhouse gas than CO2.

• It only takes a year for atmospheric gases to travel around the earth. • One unit weight of Carbon C is equal to 44/12 unit weights of CO2. • When talking about carbon we must accommodate the idea of carbon pools, sinks and fluxes. Carbon pool - A system having the capacity to accumulate or release carbon. Examples of carbon pools are forest biomass, wood products, soils, and the atmosphere. Carbon sink – A carbon pool that is increasing in size. A carbon pool can be a sink for atmospheric carbon if, during a given time interval, more carbon is flowing into it than out of it. Carbon flux - The transfer of carbon from one carbon pool to another.

• The IPCC (Intergovernmental Panel on Climate Change) recommends default values of 0.5 t of Carbon in dry organic matter. (Therefore 1 tonne of dry wood which contains about ½ t. C = 1,8t of CO2)

HOW IS CO2 STOCKED IN THE BIOSPHERE ? Plants are the starting point of the carbon cycle. They absorb carbon from the air as CO2 and incorporate it into their biomass (leaves, wood, roots, flowers, fruits) through photosynthesis : 6CO2 + 6H2O + Light Energy = C6H12O6 + 6O2 Cellular respiration returns CO2 to the atmosphere when organic molecules are oxidised for energy, (e.g. sugars C6H12O6 ) :

C6H12O6+6O2 ----------> 6CO2+6H2O+36ATP The cycle of photosynthesis and respiration maintains the balance of carbon dioxide and oxygen on earth. Plants are net producers of oxygen, hence we survive …

Terrestrial carbon is captured in : 1. 2. 3.

Trees & shrubs, The soil. Grass & other herbaceous plants,

CARBON MOVEMENTS IN FOREST ECOSYSTEMS Case study - Carbon cycle at the Montmorency Forest, Quebec, Canada, research by Laval University

http://ecosys.cfl.scf.rncan.gc.ca/dynamique-dynamic/carbone-carbon-eng.asp

The study site is a 1 ha. forest stand of Balsam Fir (Abies balsamea) and Black Spruce (Picea mariana). Precipitation is abundant both in winter and summer. The growing season lasts only three months.

The forest has been fixing carbon for 60 years, in wood, roots and plant litter. As long as it was growing, the forest was a carbon sink.

The quantity of carbon present in this ecosystem, (the carbon pool), is now stable.

Photosynthesis still fixes carbon, but an equal amount is released by the respiration of all the organisms (plants and animals) living in the forest. The carbon pool at the Montmorency Forest site contains 634 t CO2 /ha), distributed as follows:

Wood Leaves Roots Humus Mineral soil Total

kg C/m² t. CO2/ha. 4.50 165.0 1.50 55.0 1.30 47.7 3.00 110.0 7.00 256.7 17.3 634.4

% 26 9 8 17 40 100

% % % % % %

Carbon fluxes 36.6 t.CO2 /ha. enters the ecosystem each year through photosynthesis.

Tree respiration releases 18.3 t.CO2/ha./yr. (50% is root respiration - energy needed to absorb nutrients from the soil.) 2,2 t.CO2 /ha./yr. or 6% of the carbon fixed by photosynthesis accumulates as biomass in trunks and roots; the quantity of carbon in the leaves and branches of mature trees remains stable. 16,1 t.CO2 /ha./yr. makes its way into the plant litter (dead leaves, branches and trees) and the soil (roots). In the soil, respiration by the decomposers 16,1 t.CO2 /ha./yr.

is

Conclusions : Soil carbon pools are in equilibrium because the amount of carbon released into the atmosphere (respiration) is equivalent to the quantity fixed in the plant litter.

In this type of forest, vegetation represents the only carbon sink. However, it is not very efficient, accumulating barely 2,2 t.CO2 /ha./yr. Overall, equilibrium has almost been achieved, but could be disrupted by a disturbance, such as fire or insect infestation, that could cause the site to become a major carbon source.

TUFTS UNIVERSITY (U.S.A.) website The Tufts University in the U.S has published figures for carbon capture in forests. http://sustainability.tufts.edu/?pid=74 “From: Forests and Global Change, Vol. 2, Forest Management Opportunities for

Mitigation of Carbon Emissions. Neil Sampson and Dwight Hair, Washington, 1996.

Northeast, maple-beech-birch forests

25 year old forest : 12,000 lbs of carbon / 25 = 480 lbs of C per acre per year x 44/12 =1,760 lbs of CO2 per acre per year = an average of 2.52 lbs of CO2 per tree per year. 120 year old forest : 128,000 lbs of carbon / 120 = 1,066 lbs of C per year per acre x 44/12 =3,909 lbs of CO2 per acre per year = an average of 5.58 lbs of CO2 per tree per year.

Tree density varies, and we used an average of 700 trees per acre (this number was taken from DOE's "Sector-Specific Issues and Reporting Methodologies Supporting the General Guidelines for the Voluntary Reporting of Greenhouse Gases under Sections 1605(b) of the Energy Policy Act of 1992"

Tonnes of CO2 / ha. / yr. CO2 capture in forests 12.00

11 t.

t. CO2 / Ha. / yr

10.00

2 t.

8.00 6.00 4.00 2.00 0.00 Broadleaf forest Broadleaf forest Pine forest 25 Pine forest 120 25 yrs 120 yrs yrs yrs

THE SOIL “Soil organic carbon is the largest reservoir in interaction with the atmosphere”

(United Nations Food & Agriculture Organisation)

On Earth : • 650 gigatons of carbon is stored in vegetation, • 750 gigatons in the atmosphere, • 1500 gigatons (1,5 x 1012 t) of carbon stored is contained in organic topsoil.

"Enhancing the natural processes that remove CO2 from the atmosphere is thought to be the most cost-effective means of reducing atmospheric levels of CO2.“

(US Department of Energy)

The soil stocks carbon as humus. Humus is formed by the action of the micro-fauna, fungi and bacteria on plant residues.

Humus can stay in the soil for thousands of years. Organic carbon is sequestrated naturally when climatic conditions are favourable. (T < 25°C and adequate precipitation).

Moorland peat

Peat = 40 – 45 % Carbon

Organic matter originating from leaves & roots of grasses indicates the important role that surface vegetation plays in carbon sequestration.

The maths behind Soil Carbon

Example : • A 1 hectare park or field (10,000 m²) • The topsoil is 32 cm deep • Soil density = 1.5 tonnes per cubic metre • Soil mass per hectare = 4,800 tonnes • 1% change in soil organic matter = 48 tonnes • Which is about 28 tonnes of Soil Carbon • This 1 ha. park will sequester an extra 100 tonnes of atmospheric CO2

How is it possible to enhance the natural processes that remove CO2 from the atmosphere to the soil ? This was the starting point for the TOP GREEN research station at Les Alleuds, France to look at the way turf grasses respond to carbon sequestration because they have a high density foliage cover and dense root systems. “Grasses have fibrous root systems with an average dry root mass of 1,5 kg per m², which represents about 70% of the total plant mass.” Effect of management intensity on sward productivity of a permanent meadow Stypinski P. Mastalerczuk G. 2002

FIBROUS ROOTS - DO THE MATHS !! 1.5 kg of fibrous roots per m² (dry organic matter) = 15 000 kg or 15 tonnes per hectare, = 7 500 kg carbon,

= 7 500 x 44/12 kg CO2, = 27.5 tonnes of CO2 captured and pooled in the grass roots per hectare.

HOW DO FORESTS AND GRASSES COMPARE FOR CAPTURING CO2 ? In trees, carbon is mainly locked in the trunks as lignin with a ratio of 80 : 20 above ground to below ground biomass.

In grasses, carbon is in the fibrous roots, invisible to the naked eye, representing an underground biomass of 70 – 90%.

RESEARCH ON MEADOW AND PASTURE GRASSES. Management

sequestration (tons C/acre/yr)

Conversion of cropland to perennial grassland

0.07-0.54

Introduction of earthworms

1.05

Manure or fertilisation

0.03 – 2.0

Rotation with meadows / cover crops

“minor” to 1.1

Use of improved grass species

1.36

References Haynes et al. (1991); IPCC (1996); Mensah et al. (2003); Tyson et al. (1990) Conant et al. (2001) Lal (2003), citing Ridley et al. (1990), Dersch and Bohm (2001), Malhi et al. (1997), Kundu et al. (2001), and Uhlen and Tveitnes (1995) Lal (2003), citing Curtin et al. (2000) and Uhlen and Tveitnes (1995); ISCC (2003) Conant et al. (2001)

1.36 tons of C = 4.99 t CO2 / acre /yr = 12.33 t CO2 /h./ yr

Research on carbon capture & sequestration for grass species has been carried out in turf grasses by TOPGREEN for : • • • • • •

Rye grass, Hard Fescue, Red Fescue, Agrostis stolonifera, Smooth Meadow-grass, a mix with micro-clover

Turf grass carbon sequestration field trial conditions • Autumn sowing 2005 • Samples 12/03/2008 (30 months) • 5 species & 1 clover mix • 3 samples per species, total 18, • 10cm de diameter samples to 20cm depth (= 1570cm3) • Identical plot management • Each sample dived into 3 parts to investigate soil, root and leaf carbon contents. • Pre-trial soil organic matter measured at 1,62% = 77,6t of C0²/ha sequestered in the soil.

CO2 content of control sample without grass cover 1m3 of soil with 1.62% of organic matter

units

x Density 1,5 1 500 000 grams x 1.62 % Organic Matter (from soil analysis)

24 300 g./ m²

Divided by 1.72 (proportion of carbon in organic matter)

14 128 g./C/m²

x depth (soil analysis)

2 119 g./C/m²

x 44/12 (convert C to CO2)

7 769 g./CO2/m²

Convert to t / H.

77,69 t./CO2/ha.

Tonnes of CO2 per hectare in turf grass

CO2 CO2 CO2 total CO2 soil leaves roots plant Eurospace Eco-trifolium

9.92

13.62

115.51

91.92

4.42 20.60

25.01

116.93

Hard Fescue

112.97

3.46 14.17

17.63

130.60

Rye grass

126.18

4.56 11.61

16.17

142.34

Agrostis stolonifera

129.20

5.48 15.96

21.44

150.64

89.53

6.17 47.26

53.44

142.96

Smooth Stalked Meadow Grass

Red Fescue

101.89

3.70

CO2 total soil & plant

Tonnes of sequestrated CO2 per year (soil) and captured (roots & leaves) in turf grasses

35.00 30.00 25.00 20.00 15.00

average

10.00 5.00 0.00 Eurospace Eco-trifolium

Smooth Meadow Grass

Hard Fescue Rye Ray grass

Agrostis Red Fescue Average stolonifera leaves roots soil

Compared annual sequestration rates between forests, meadows and turf grasses 14.00 12.00

8.00 6.00 4.00

maxi 2.00

TURF GRASS

t. CO2 / Ha. / an

10.00

mini

0.00

Broadleaf forest 25 ans

Broadleaf forest 120 ans

Pine forest 25 ans

Pine forest 120 ans

Natural meadow

Average Grass species

CO2 SUMMARY OF TURF GRASSES

Leaves stock 3.7 – 6.2 t. CO2 / ha Roots stock 4 – 27,5 t. CO2 / ha. together they transfer

in to the soil, 5.6 – 20.6 t. CO2 per year

Observations for the turf grass results : 1. Can we assume the carbon content to be proportionally sequestrated in the 2½ year span, ? probably not (the first 6 months from

October to March 2005 is not a representative growing period = seeding + winter).

2. What happens to carbon sequestration with soil depth?, (We need to confirm a probable

decreasing sigmoid curve.)

3. The carbon in the plant tissue was removed by mowing, what happens when it is not.

4. Have the grass roots reached a maximum root density in only 2½ years, probably not ?

THE ENVIRONEMENTAL BENIFITS OF GRASSES.

Grasses fulfil a more complex role in the urban ecosystem : • Grasses help prevent soil erosion, • Grasses filter dust and particles from the air, • Lawns filter water into the water table thereby avoiding excess runoff and flash flooding, this is aided by increased earthworm activity, • Grass regulates, along with other plants, the temperature gradients in towns and cities, • Grass acts as a filter absorbing rather than reflecting noise, 1 ha. of grass produces enough O2 for 150 people to breath, Société française des gazons.

THE TEMPERATURE GRADIENT IN CITIES

The creation of ”coolspots” for the inhabitants is an efficient way of reducing the effects of global warming in towns & cities. 7 – 10°C difference

town countryside

water

town park

WHAT ARE THE CO2 EMISSIONS OF LANDSCAPE MAINTENANCE OPERATIONS ? This is a question currently being investigated by the Carbon commission of the Société Française des Gazons in France, with the participation of Landscape & Environmental Services Ltd. Green keepers and managers of golf courses, football pitches, highway authorities and public parks have been participating in a nationwide study to determine carbon footprints in the landscape industry.

Is your Landscape maintenance

CO2

?

Or

? CO2

If so where ?

Case study : A carbon audit of Romsey War Memorial Park, Hampshire.

Landscape & Environmental Services Ltd.

Romsey War Memorial Park

Flower beds Shrub beds Hard surfaces Play area Bowling Green Tennis courts Bowling Club Grass area Trees Total

m² 152 469 2016 658 1500 1000 5795 14153 69 (nb) 19948

Shrub beds nb. Shrubs 47 65 48 84 132 98

Kg. CO2 in shrubs kg above roots CO2 ground 33.09 1 166 389 15.71 766 255 9.80 353 118 5.50 347 116 1.60 158 53 0.15 11 4 Total 2 801 934

total 1 555 1 021 470 462 211 15 3 735

Hedges The hedges stock 4 486 kg / CO2 eq. Because they are cut each year, most biomass is removed with only a negligible biomass is being added.

The carbon emissions through maintenance almost certainly outweigh CO2 sequestration.

Lawns Based on the information received the grass varieties in place are over 30 years old. Based on research data we estimate that parkland amenity grass has an intermediate carbon content between meadow grassland and turf grass.

Taking into consideration sward density and carbon sequestration from the soil samples in the soil under the grass the lawn carbon content is calculated for the : leaves = 3 220 kg.

(cutting height = 5cm), roots = 16 915 kg

Soil analysis A soil analysis showed a S.O.M. (soil organic matter) of : • Control – 10%, • Borders – 10.4%, • Lawns – 16.2% The control sample was taken from a zone without vegetative cover. The difference between the lawn and control soil samples is explained by carbon sequestration of the grasses. The annual sequestration rate for the shrub borders soil remains undefined because of added mulch. SOIL

shrub borders lawns

m²

469 14153

Pooled Sequestration t. CO2 t. CO2 / yr 11.01 241.53 5.69

Trees

An existing tree survey was used as a basis for calculations. Samples trees were remeasured for height and d.b.h (diameter at breast height). From the calculated biomass the the carbon content was assessed for different species using either allometric equations or IPCC default data.

Core samples were taken for dendrochronological analysis to determine increment growth rates and calculate the annual increase in biomass. By cross checking the probable projected growth rates with allometry tables it was possible to estimate future annual C02 sequestration for trees. It was noted that annual increment growth rate lowered for a long period from about 1956 – 1970, the cause remains unknown, (frequent heavy tree pruning on certain species, roots cut when putting in footpaths or environmental factors ?)

35 yr. CO2 set back

The sequestration of CO2 above is represented as a yearly average for the life of the tree. 55 years ago a dramatic event slowed tree growth, setting back the annual carbon sequestration rate for 35 years.

Nb. 2 6 20 5 4 5 3 2 2

20

69

Species Fagus sylvatica purpurea Prunus cerasifera 'Pissardii' Tilia cordata Tilia platyphyllas Metosequaia glyptostroboides Prunus avium Tilia x europaea Cercidiphyllum japonicum Salix babylonica Laurus nabilis Nyssa sylvatica Alnus glutinosa Aesculus x carnea Cratoegus crus-gallii Aesculus hippacastonum Prunus sargentii Betula papyrifera Pinus muga Zelkava carpinifolia Picea abies Pteracarya fraxinifolia Quercus robur Acer griseum

height cm dbh stocked range m range CO2 kg

probable av. yearly increase CO2 1 - 5y

10 - 15 10 - 15 10 - 20 3-5 5 - 15 5 - 15 12 - 15 9 - 12 12 - 15

6 - 60 10 - 36 30 - 68 5-8 10 - 15 6 - 36 45 - 50 25 - 30 30 - 60

5 017 6 977 64 476 127 281 2 796 7 184 1 417 3 653

93 309 1 469 10 22 124 137 81 158

5 - 15

6 - 30

3 475

191

95 401

2 593

SUMMARY OF CARBON SEQUESTRATION IN ROMSEY WAR MEMORIAL PARK annual sequestration m² CO2 content kg CO2 kg / yr Shrub beds 469 m² 3 735 negligible (pruning) Soil (shrub beds) 469 m² 11 010 Lawns 14 153 m² 20 135 Soil (lawns) 14 153 m² 241 530 5 690 Soil (background level) 14 622 m² 402 471 Trees 69 95 401 2 593 Hedges 295 m 4 486 negligible (pruning) 778 768 8 283

ROMSEY PARK CO2 MAINTENANCE EMISSIONS

CARBON EMISSIONS

A questionnaire relating to energy consumption, fertiliser & pesticide use was sent to and returned by the park’s department. It should be noted that the Park’s department has adopted a 0% pesticide use and no nitrogen fertiliser is used in the park.

Park machinery Mower Strimmer Hedge Cutter Leaf Blower Chain Saw Rotovator Oil changes

kg. CO2. yr % of total 575.25 37.8% 28.24 1.9% 22.60 1.5% 65.90 4.3% 7.53 0.5% 15.34 1.0% 59.00 3.9% Total 773.86 50.9%

Transport Pick-up Supervisor Van & Grass cutting Trailor General gardening Mulch imports Leaf sweeping Snow clearing Tree surgery General Pruning Hedge cutting Road sweeping Waste removal Total TOTAL

82.41 98.79 145.28 3.29 6.59 3.29 38.74 13.17 6.59 39.52 309.94 747.62 1521.48

5.4% 6.5% 9.5% 0.2% 0.4% 0.2% 2.5% 0.9% 0.4% 2.6% 20.4% 49.1%

CONCLUSIONS Romsey War Memorial Park, has a carbon pool of 778 tons of C02 eq Annual sequestration = 8.2 tonnes / yr. Carbon emissions = 1.5 tonnes / yr. Exclusion Office / administrative (carbon) overheads

Reducing carbon emissions is part of a more general sustainable landscape management approach which would include many other factors, reduced pesticide use and alternative weed killing techniques, recycling biomass, the creation of urban meadows, ISO 14001 …. … which was put into place for Lyon city park’s department.

A last thought about the consequences of global warming …

………. And in 2012 ?

Petagrammes per year

8 6

4 Carbon emissions

2

Carbon absorption

1750

1800

1850

1900

1950

0 2000

THANK YOU

Howard Wood

. Landscape & Environmental Services