Rising temperatures and surging pests are pushing Bhutan’s iconic mandarins uphill, forcing lowland farmers to rethink crops and livelihoods as climate change redraws the kingdom’s citrus landscape.

Rising temperatures, increased pests, and disease linked to climate change are driving Bhutan’s mandarin cultivation to higher altitudes, compelling farmers in lower regions to adapt by shifting crops, livelihoods, and farming practices.

This quiet but profound transformation is redrawing the kingdom’s citrus map, once dominated by the warm, subtropical valleys of southern and central Bhutan. What was long considered the heartland of mandarin orchards – lush groves that supplied domestic markets and earned precious export revenue – is now becoming less hospitable. Scientists and farmers alike describe a northward and upward migration of the fruit that has defined rural economies for generations.

The shift is not voluntary. As average temperatures climb across the Himalayan kingdom, conditions that once favoured mandarins in the lowlands are turning hostile. Warmer winters and erratic rainfall patterns allow pests such as the citrus psylla and various fungal diseases to thrive year-round. What used to be seasonal threats have become persistent plagues, devastating yields and forcing growers to spray more chemicals – an expense many smallholders can ill afford.

Warmer Weather and Pests Trigger an Altitudinal Exodus

In districts traditionally known for mandarins, such as those in the lower elevations of Tsirang, Dagana, and parts of Sarpang, farmers report trees struggling to fruit properly. Leaves yellow prematurely; fruits drop before ripening; entire orchards that once produced thousands of kilograms now yield a fraction. One veteran grower in a southern valley recently described watching his family’s 20-year-old grove decline over just five seasons: “The heat comes earlier and stays longer. The bugs never leave.”

With low-altitude farms faltering, mandarins are literally moving uphill. Cultivation is expanding into mid-altitude zones – areas once considered too cool or too risky for commercial citrus. Farmers in higher valleys are experimenting with new plantings, reporting better fruit quality and fewer pest outbreaks in the cooler, cleaner air. This altitudinal migration echoes patterns seen in other Himalayan regions, but in Bhutan it carries special weight: citrus has been a cornerstone of smallholder income, rural employment, and even cultural identity.

The government’s agriculture ministry has begun tracking the phenomenon through field surveys and satellite imagery. Early data suggest that suitable zones for mandarin production could shift 200–400 metres higher within the next two decades if warming trends continue. That projection carries both risk and cautious optimism. Higher altitudes may offer respite from heat and pests, but they also present new challenges: thinner soils, steeper slopes prone to erosion, and shorter growing seasons. Infrastructure for irrigation, roads, and market access is often poorer in these emerging zones.

Farmers in Lowlands Face Hard Choices on Crops and Income

Farmers in the traditional lowlands are responding with a mix of resilience and reinvention. Some are intercropping mandarins with more climate-resilient species – avocados, macadamia nuts, or vegetables that tolerate warmer conditions. Others are abandoning citrus altogether, converting orchards to paddy, maize, or to fodder for livestock. A growing number are turning to agro-tourism, opening homestays amid the remaining groves and offering visitors “mandarin experiences” before the landscape changes forever.

Yet the human cost is real. Many older farmers lack the capital or knowledge to switch crops quickly. Younger generations, already migrating to urban centres for jobs, see little future in farming under uncertainty. Village cooperatives that once pooled resources for pest control and marketing are now debating whether to invest in new high-altitude plots or diversify entirely.

Experts from the National Centre for Plant and Soil Sciences emphasise that Bhutan cannot simply “follow” the mandarins uphill without strategic planning. They call for accelerated research into heat-tolerant rootstocks, integrated pest management that reduces chemical use, and climate-smart varieties developed through collaboration with international citrus institutes. Training programmes for farmers on soil conservation and water harvesting are already underway in pilot districts, but scaling them nationally will require significant investment.

New Opportunities for “Climate Dividend”

The economic stakes are high. Mandarins have long been one of Bhutan’s few agricultural export success stories, reaching markets in India and beyond. A shrinking lowland harvest could squeeze rural incomes and foreign-exchange earnings at a time when the country is also grappling with broader climate impacts – glacier melt, erratic monsoons, and rising disaster risks.

Still, the story is not only one of loss. The upward march of mandarins may open doors for previously marginalised highland communities to participate in commercial agriculture. With proper support – improved roads, cold-storage facilities, and marketing linkages – new growers could supply premium, pest-free fruit that fetches higher prices. Some agronomists even speak of a “climate dividend” if Bhutan positions itself as a producer of high-altitude, organic citrus.

What the Future Holds for Bhutan’s Citrus Economy

For now, the landscape is in flux. Orchards that once blanketed southern slopes stand thinner and more scattered. Higher up, tentative new plantings dot hillsides that were meadows or forests only a decade ago. The mandarins are on the move, and Bhutan’s farmers, policymakers, and scientists must move with them.

The kingdom’s Gross National Happiness philosophy, which places equal weight on economic progress and environmental stewardship, faces a practical test here. How Bhutan manages this agricultural transition – balancing adaptation, equity, and sustainability – will shape not just its citrus map but the resilience of its rural heartlands for generations to come.

As temperatures continue their inexorable rise, the mandarins’ journey uphill serves as a living barometer of climate change in the Himalayas. The question is no longer whether the map will be redrawn, but how thoughtfully Bhutan draws the new lines.

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