Spatially explicit estimates of forest carbon emissions have helped identify the most cost-effective use of REDD+ resources (for Reducing Emissions from Deforestation and forest Degradation plus conserving, sustainably managing forests and enhancing forest carbon stocks) in Indonesia. Included in the list are low-cost options for protecting areas from conversion to oil palm and timber plantations – conservation strategies that are often considered expensive to implement.


"Indonesia is home to some of the most irreplaceable and threatened ecosystems in the world, for example, the Leuser Ecosystem in northern Sumatra is the last place where four critically endangered animals – Sumatran tigers, rhinoceroses, elephants and orangutans – still co-exist in the wild," Victoria Graham of James Cook University, Australia, told environmentalresearchweb. "The protection of these forests is of international interest and this research draws attention to this issue and supports Indonesian policymakers to better integrate environmental objectives into development plans."

It is estimated that 1.5 million hectares of Indonesian forest are lost on average each year as land is logged, burnt and replaced by oil palm and timber estates to stimulate economic growth. Adding to the challenge, the financial burden of programmes to reduce emissions from tropical forest loss can appear high when considering average costs across large land areas, but this hides a large number of affordable locations for REDD+.

To provide more detail, the group ranked thousands of forest sites across Indonesia by the cost of reducing one tonne of carbon emissions. The results range from less than $2 per tonne of carbon to more than $8000 per tonne of carbon depending on factors such as land productivity and soil type.

Forest priorities

According to the data, high priorities for reducing emissions cost-effectively include protecting forests on lowland peat swamps, abating illegal forest loss in protected areas that are exposed to a high risk of being cleared, and revoking undeveloped permits for oil palm concessions on unproductive land.

Indonesia’s commitment toward achieving the Paris Agreement is to reduce emissions by 29% below the business-as-usual level (or by 41% with international aid) by 2030. Part of this reduction will need to come from land use, land-use change and forestry. REDD+ projects targeting the cost-effective options, and restoring degraded peat forests, will maximize the emissions reduction from land use, land-use change and forestry per dollar spent.

"Our analysis also highlights a significant opportunity for logging concession holders to maintain forest cover and reduce emissions from harvesting timber by applying reduced-impact logging principles," said Graham.

Obstacles faced by the researchers when drawing up the data included overlapping administrative boundaries and inconsistent or incomplete maps. However, they hope that the "One Map" initiative will help resolve these issues by offering a co-ordinated national reference of Indonesia's forest cover and land use.

Graham and colleagues reported their study in Environmental Research Letters (ERL).