Survey data indicates that trees contribute the most biomass and have the most contained carbon of the vegetation forms, highlighting potential for remote sensing techniques to be employed to estimate carbon stocks over vast areas of the rangelands.
Several land systems in the mulga shrublands of Western Australia’s (WA) Murchison region were surveyed to provide scientific information to land managers on the distribution of and potential for sequestered carbon.
Rangelands NRM is working with other partners on the Carbon Awareness Project which is funded under the WA Government Royalties for Regions program.
Rangelands NRM’s work, led by Senior Rangeland Scientist Dr Peter Russell, began in 2013 with a field survey to estimate the amount of above-ground vegetative biomass and contained carbon within the Yanganoo-Belele land system on Meka Station, about 100 km north of Yalgoo and 100 km west of Cue in the WA rangelands.
The data showed very strong statistical relationships between selected plant dimensions and the amount of contained carbon, except for grasses for which the relationship was only moderately strong.
“Trees, the largest vegetation, containing most of the carbon, could be mapped and measured with remote-sensing techniques,” said Dr Russell.
Using remote sensing to measure the carbon sequestration potential of the WA rangelands is the subject of a proposed study, needed to drastically reduce the cost of carbon stock surveys.
“Over the course of several surveys in 2013 and 2014, the team improved field sampling and measurement techniques and, in light of these improvements, decided to collect additional plant measurements at Meka to bring earlier data up to a new standard,” he said.
With several surveys and data analysis now completed, results for the Yanganoo-Belele land system on Meka include:
- the total amount of above-ground biomass (all vegetation including ground litter) ranges between 7.2 and 107.4 tonnes/hectare (t/ha) and averages 34.4 t/ha
- trees contribute between 16 per cent and 97 per cent of the total biomass, averaging
80 per cent
- biomass contributions by the other vegetation forms are, on average, shrubs: 10.9 per cent, standing dead: 7.3 per cent, ground litter: 1.2 per cent, and perennial grasses: 0.6 per cent
- all of this biomass contains carbon amounting to 16.2 tC/ha on average, ranging from a miserly 2.9 tC/ha to a hefty 50.6 tC/ha.
For those contemplating new carbon abatement projects, Dr Russell said it is not too early to develop a business case or strategy to incorporate new carbon abatement work into an existing enterprise or land management plan.