Chiuri fruit. Image by Bishnu P. Acharya

Chiuri, otherwise known as the Nepali butter tree [Diploknema butyracea (Roxburgh) H. J. Lam], is one of the most important tree species in Nepal. Its oil-rich seeds are used in a variety of ways by rural households and businesses, including for confectionery, pharmaceuticals and traditional medicines, cosmetics, candles, soap, and vegetable ghee/butter. 

“Chiuri is a multipurpose tree species,” said Bishnu Prasad Acharya, a divisional forest officer for the country’s Dhading District – “not only from the economic and ecological viewpoint, but also culturally: for example, it strongly features in the cultural practices of the ethnic minority Chepang communities of central Nepal.”

Now, scientists and local stakeholders are exploring how to optimize the species’ potential to support vulnerable rural populations and serve up resilient, sustainable livelihoods in the face of climate change.

Chiuri grows throughout the Himalayan belt (Nepal, India and Bhutan) at altitudes of 300–1500 metres above sea level. It’s a fast-growing, medium- to large-sized broadleaved tree that can reach up to 25 metres in height, and produces sweet fruit that can be harvested for 50–60 years.

The tree’s processed seeds produce a richly-flavoured, nutritious fat, which is known as chiuri ghee or butter and is used for cooking throughout the region, as well as to alleviate headaches, rheumatic pains, ulcers, itching, tonsilitis, and chapped skin. Many rural Nepalese households also use the fat as fuel for their lamps. 

Chiuri tree. Image by Bishnu P. Acharya

Meanwhile, chiuri leaves serve as nutritious fodder for cattle, and the residue of the leaves can be made into green manure, while the twigs are used as fuelwood. The tree binds soil and adapts well to slopes and barren land that is comparatively infertile, making it an excellent candidate for landscape restoration. It also provides food and shelter for bats, birds, and a range of insects, including honeybees.

However, there are considerable gaps in knowledge about the species, which obstruct its optimization for human and planetary benefit. 

“One of the major challenges is that we don’t know exactly where chiuri grows, how many trees exist, what ages they are, and the yields and uses for each region in Nepal,” said Himlal Baral, a senior restoration scientist at CIFOR-ICRAF. “We do know that there is inadequate processing, value addition, product diversification, and market exploration – and a general lack of studies of the species.”

However, researchers say that there is enormous scope and a wide resource base for establishment of chiuri-based, micro-to-small-scale enterprises. These could produce, for instance, high-quality and diverse chiuri butter products, as well as honey, which is also a popular food in the region.

“Chiuri butter already has an economic value for Nepal of over NPR 5 billion [USD 38 million],” said Oli Bishwa Nath, a research associate at the Center for International Forestry Research and World Agroforestry (CIFOR-ICRAF) and former secretary of Nepal’s Ministry of Forest and Environment. “And we could be making a lot more of it: potentially, 37,245 tonnes of chiuri butter and 17,285 tonnes of honey could be produced from the approximately 11 million chiuri trees growing across the country.”  

Chiuri flower. Image by Bishnu P. Acharya

To help protect and develop this critical resource further, Oli called for a national resource inventory of chiuri and support from government agencies for conservation projects, alongside helping farmers diversify products from the species, building their capacities in business, and preserving traditional knowledge, backed by research into ecosystem services. “All of these measures are vital for helping farmers – and the nation – to adapt to the climate crisis, while also sequestering more carbon to contribute to mitigation,” he said.