Hosing down hype but not burying hope

Ten years ago there were high hopes that an oil-bearing tree or shrub could be part of the answer to the world’s quest for biofuel. By now the ‘hype’ has almost been forgotten. As in most of these cases, neither the hope nor hype nor the subsequent disappointment were fully justified: the truth was somewhere in the middle.

 

Jatropha species (‘jarak’ in Indonesia) were thought to be that wonder plant. It would be able to grow on poor soils, not compete with food crops, provide income opportunities where there were few before, decrease dependence on fossil fuels and help provide energy in remote locations.

It took a while to fund the research projects that would test these ideas and more time for the research to be done, digested and published. Part of the challenge in assessing the potential of jatropha was that not enough was known about its growth habits (‘tree or shrub’) or the way aboveground biomass translated into harvestable fruit.

‘That question was the focus of our recently published study’, said Juliana Teuw, a PhD candidate at Wageningen University in the Netherlands, who is associated with the World Agroforestry Centre Indonesia program. ‘Our work showed that existing tree-based branching models had to be adjusted to account for the multi-stemmed habit of jatropha at our research sites. Jatropha roots act as storage organs and belowground biomass is higher than what is expected if standard equations are used’.

Jatropha seeds. Photo: Center For International Forestry Research/Jeff Walker

Jatropha seeds. Photo: Center For International Forestry Research/Jeff Walker

Fieldwork for the study was focused on Gunungkidul in Central Java Province, an area known for its poor and degraded soils.

‘The wider context of jatropha is that we need to learn from the past hype and be ready with more solid research when new ideas on biofuel crops emerge because the need for those still exists’, said Dr Maja Slingerland, also from Wageningen University and  co-author of the study.

‘The agroforestry research toolbox that we have developed over the years can be used to assess any plant, whether tree or shrub, in any planting pattern combined with other crops or known trees’, added Dr Meine van Noordwijk, chief science advisor for the World Agroforestry Centre, who is based in Indonesia. ‘But field testing is needed to check the models and, as this study shows, refinement is needed to get more reliable assessments of the potential. In this case, better understanding of the low harvest index—which is the harvested fruit per unit of aboveground biomass—is the key to selecting cultivars with a productivity that would make them interesting for farmers. The previous “hype” was premature because planting material wasn’t sufficiently adjusted to local circumstances. We need to learn lessons for how to systematically assess a wider range of options before public “hopes” turn to “hype”’.

 

Read the article

Tjeuw J, Mulia R, Slingerland M, van Noordwijk M. Tree or shrub: a functional branch analysis of Jatropha curcas L. Agroforestry Systems. DOI: 10.1007/s10457-015-9819-5

 

 

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This work is linked to the CGIAR Research Program on Forests, Trees and Agroforestry

 

Rob Finlayson

Rob Finlayson

Robert Finlayson is the Southeast Asia program's regional communications specialist. As well as writing stories for the Centre's website, he devises and supervises strategies for projects and the countries in the Southeast Asia region, including scripting and producing videos, supervising editors and translators and also assisting with resource mobilization.

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