Technical Information

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Licensed under Creative Commons Attribution 3.0 Australia. © Crown in right of the State of South Australia.

Technical Information

How much carbon is stored in our trees?

This document describes the sources of information, advice, methods, indicators and data processing procedures used to develop the report cards. Reliability of data, as well as metadata attributes, are also described.

State NRM Plan Guiding Target:

Maintain the productive capacity of our natural resources.

State NRM Plan Representative Measure:

Total carbon sequestered (above ground and in soil).

Data collection period:

2012.

Expected frequency of reporting:

Annual.

Data sources:

1. Department of Environment, Water and Natural Resources (DEWNR).

Indicators used:

1. Estimate of carbon stored in remnant woody native vegetation (tonnes of carbon per hectare and total tonnes).

2. Current extent of remnant woody vegetation in private and public lands (hectare, excludes non-woody vegetation for example herbfields, grasslands, sedgelands, low shrublands and very sparse tree/shrub plant communities).

Methods of data collection and processing:

The above-ground carbon storage (as standing biomass - total tonnes of C) of remnant vegetation is based on land use and vegetation mapping and the application of models developed for estimating the amount of carbon stored by revegetation (Hobbs et al. 2013).

The spatial models of carbon in remnant vegetation (Hobbs et al. 2013) are based on 37 surveys of remnant mallee and woodland vegetation across a rainfall gradient 333 – 843 mm/year (32 sites in a “transect” from Mt Lofty to Upper Yorke Peninsula; and 5 mallee and woodland sites in the South Australian and Murray Darling Basin and South East NRM regions). Surveys include destructively sampling woody trees and shrubs (including Atriplex sp.). For details on survey methods see DEWNR technical report (Hobbs et al. 2013). Estimates includes only remnant native woody vegetation greater than 2 meters. Estimates do not include roots, plant litter or small shrubs. The models have been applied to arid areas of the SA Murray-Darling Basin, Northern and Yorke, and Eyre Peninsula NRM regions according to vegetation type and extent, but confidence in estimates are lower than the non -arid areas.

Results are spatially constrained to the lower NRM regions and the limits of South Australian soil mapping.

Data presented are elemental carbon weights. To convert to a carbon dioxide emissions equivalent carbon mass should be multiplied by 3.67 to account for the additional molecular weight of oxygen.

Methods to calculate trends and current condition

Current levels of carbon are a modelled estimate based on the area of remnant woody vegetation (excludes non-woody

vegetation for example herbfields, grasslands, sedgelands, low shrublands and very sparse tree/shrub plant communities). Trends in the area of vegetation is considered to be stable according to the relative extent of vegetation cleared since 1991, when native vegetation was protection by legislation. Note that this does not account for fire and climate – as noted in the report card.

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The current condition (where we are at), classified as good (>66%), fair (33-66%) or poor (<33%), is based on the percentage of carbon compared to historical stocks (pre 1750). Scores are related to historical clearance and do not reflect recent NRM investments.

The amount of vegetation that is cleared from agricultural areas is higher than in non-arable areas, for example 94 per cent of vegetation remains in the arid areas of the Northern and Yorke NRM region, but only 26 per cent of vegetation remains in the southern area. Agricultural areas typically have more carbon per hectare (larger and denser trees hold more carbon), so the level of remaining carbon stocks is lower than remaining vegetation extent.

Future reporting measures:

Future report cards should include carbon stock estimates for the SA Arid Lands and Alinytjara Wilurara NRM regions. Although the amount of carbon in vegetation on the arid areas is relatively small per unit area, the large areas involved means that total carbon can be large. How much is retained over time is highly dependent on the intensity of grazing. Estimation by remote sensing is feasible and should be explored over time.

Carbon in revegetated lands is an important aspect in terms of tracking carbons stocks, and maintaining productive capacity of our lands. To calculate carbon in revegetated lands there needs to be a reliable record of revegetated lands on private and public land, the area, the species planted and the methods of planting. This information should be collected through NGOs such as Greening Australia, Trees for Life, that has a vested interested in revegetation.

The following government agencies contributed to this report card:

DEWNR.

The following non-government agencies contributed to this report card:

None.

Key stakeholders:

NRM Council, NRM Boards, agricultural land owners/managers, Primary Industries and Regions SA (PIRSA), agricultural industry groups, DEWNR.

Information reliability scoring:

Information is scored for reliability based on average scores given for information currency and applicability, and its level of spatial representation (Tables 1–3).

Table 1. Information currency Reliability Criteria

5 Information up to 3 years old 4 Information up to 5 years old 3 Information up to 7 years old 2 Information up to 10 years old 1 Information >10 years old

Table 2. Applicability of the information Reliability Criteria

5 All data based on direct indicators of the measure 4 Most data based on direct indicators of the measure 3 Most data based on indirect indicators of the measure 2 All data based on indirect indicators of the measure 1 Data are based on expert opinion of the measure

Table 3. Spatial representation of information (sampling design)

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Reliability Criteria

5 Information is collected from across the whole region/state (or whole distribution of asset within the region/state) using a stratified sampling design

4 Information is collected from across the whole region/state (or whole distribution of asset within the region/state) using a sampling design that is not stratified

3 Information is collected from an area that represents less than half the spatial distribution of the asset within the region/state

2 Information is collected from an area that represents less than 25% the spatial distribution of the asset within the region/state

1 Information is collected from an area that represents less than 5% the spatial distribution of the asset within the region/state or spatial representation unknown

Based on tables 1, 2 & 3 above, respectively, the information relating to carbon stored in soil in this report card has a reliability score of (5+3+3)/3 = 3.67 rounded to 4 (Very good).

This report card is linked to the following report cards:

1. How much carbon is stored in our soils?

2. How many South Australians understand the causes and consequences of climate change?

3. How many climate change adaptation plans have been completed?

4. How good is the scientific understanding of the causes and consequences of climate change?

5. How much of our agricultural land is protected from erosion?

6. Is soil acidity decreasing in our agricultural areas?

7. Is soil fertility improving in our agricultural areas?

8. Is water-use efficiency improving in our agricultural areas?

9. Are the extent and connectivity of our native vegetation improving?

10. Is the condition of our native vegetation improving?

11. How much of our native vegetation is protected?

Metadata description:

Project/Dataset name: Data provided 1/10/2013

Abstract/description Dataset is a summary of the carbon stored in native remnant woody vegetation by NRM region.

Data types Spreadsheet

Organisation/ DEWNR business area that

sponsors/holds/manages the data

DEWNR

Date range 2012

Study area South Australia’s agricultural areas.

Data format Excel spreadsheet

Data distribution rules Licensed under Creative Commons Attribution 3.0 Australia Is the dataset source data (raw),

value-add data

(analysed/summarised) or final indicator/score data?

Value-add

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Photo credit details:

Owner: DEWNR.

Scientific literature referred to in the report card:

Hobbs, T.J., Neumann, C.R., Tucker, M., Ryan K.T. (2013). Carbon sequestration from revegetation: South Australian Agricultural Regions. Government of South Australia, through Department of Environment, Water and Natural Resources, Adelaide & Future Farm Industries Cooperative Research Centre.