Can’t see the forest for the (palm) trees
Oil palm plantations in Kalimantan – the Indonesian name for the island known in English as Borneo – are expanding at the expense of forest, leading to an increase in carbon emissions, according to a study published October 7 in Nature Climate Change . The study found that 90 percent of the land converted to oil palm between 1990 and 2010 was forested. Nearly half of that area was intact forest, while the rest had been logged or was being used for agroforestry.
The study was led by Kimberly Carlson, a doctoral candidate at Stanford University, using a system designed by Gregory Asner of the Carnegie Institution for Science at Stanford. Asner has been using that system to map carbon stocks in the Peruvian Amazon, as well as in Colombia and Ecuador.
Borneo’s rain forest, which is known for its biological diversity, has long been under siege, first from heavy logging and now from oil palm plantations. The new study found that carbon emissions from land conversion for oil palm plantations totaled 0.09 gigatons between 1990 and 2000 and 0.32 gigatons between 2000 and 2010, and is likely to increase to 1.21 gigatons between 2010 and 2020 if all of the leases that have been granted are developed.
Although the situation in Peru is not quite the same, partly because conversion of peatland to plantations adds a significant amount to Kalimantan’s carbon emissions in Indonesia, palm oil plantations are also cutting into old-growth forest in the Peruvian Amazon, according to a study published late last year.
From the air, the neat, new rows oil palm in the departments of San Martín andUcayali look like cross stitching. Many of the trees are being planted by small farmers hoping for something more lucrative than traditional crops. Because they have little land and little capital, their yield is lower than that of the large industrial plantations, according to the study, but they are more likely to plant on degraded land, instead of cutting down old-growth forest for oil palm. Industrial plantations are more mechanized and have higher per-hectare yield, but 72 percent of their expansion between 2000 and 2010 came at the expense of old-growth forests, according to the study, which was led by Víctor Gutiérrez-Vélez of Columbia University and published in Environmental Research Letters.
Tax breaks and a law requiring a minimum amount of biodiesel in vehicle fuel have helped spur the expansion of oil palm cultivation in Peru in the past decade. Peru has more than 50,000 hectares of oil palm now, and industry and government officials have said it could expand to 1.4 million hectares.
But the Ministry of the Environment has also set a target of zero net deforestation by 2021. Former Environment Minister Antonio Brack was adamant that plantations should not replace standing old-growth forest, but should be developed on some of the millions of hectares of degraded land in the Peruvian Amazon. The problem with that, say Gutiérrez-Vélez et al., is that those lands often have titling problems, making them less attractive to large-scale producers. So while large-scale plantations are more efficiently – meaning they could produce more using less land – they are more likely to destroy mature forest.
Fragmented forests change the hydrological cycle, are more susceptible to fire and often have less biodiversity than larger intact forests. The studies from Peru and Indonesia indicate that if palm oil plantations are to coexist with old-growth forest in Peru, there must be incentives to use degraded land, rather than destroy forest for plantations; steps must be taken to mitigate indirect impacts, such as those from roads built to the plantations; and monitoring is crucial, to be sure that oil palm does not become a net source of carbon as well as deforestation.