Harare — For five years, Mickel Giwa has grown tobacco on part of his six-hectare plot in Goromonzi, 50 km (30 miles) northeast of Harare. Curing the leaves with smoke in his barn is the next step, but that means burning large quantities of wood - most of it harvested illegally from nearby native forests.
Giwa is not alone. Zimbabwe is the world's largest producer of flue-cured tobacco after China, Brazil and the United States. High earnings from the golden leaf have fuelled a "tobacco rush" among smallholder farmers in Zimbabwe. The number of farmers growing tobacco has tripled to 90,000 since 2011, and is projected to reach 105,000 during this year's planting season.
Now the tobacco industry is trying to encourage farmers to use more fuel-efficient methods of curing their crops, worried that deforestation could ultimately be bad for business as well as for the environment.
Plantation forests and natural woodlands - key to stabilising the climate at both micro and macro levels - suffer great damage at the hands of tobacco farmers. They destroy a total of almost 50,000 hectares (124,000 acres) of forest each year gathering wood to cure tobacco, according to Violet Makoto, a spokesperson for Zimbabwe's Forestry Commission.
This is due to ignorance, poor farming practices and, until recently, a lack of alternative options, said Andrew Matibiri, chief executive of the Tobacco Industry Marketing Board.
According to data from the U.N. Food and Agriculture Organisation, Zimbabwe has around 15.6 million hectares of forest - much of it sparse, dry or open canopy forest. Between 1990 and 2010, Zimbabwe lost 29.5 percent of its forest cover, an average of 327,000 hectares per year.
At the current rate, the country may not have any forests to speak of in 50 years' time, Forestry Commission deputy director Abednigo Marufu said in an interview last year.
Small-scale farmers account for 90 percent of Zimbabwe's annual output of more than 160 million kg of tobacco, which raked in export earnings of $632 million in 2013.
But their reliance on fuel wood to cure their crops is a major cause of deforestation in Zimbabwe.
The tobacco industry has now joined the government in looking for ways to reduce the 15 percent share of deforestation accounted for by tobacco production, and to ensure the crop is grown sustainably.
One strategy for achieving that goal is the "rocket" barn, a design promoted by the Tobacco Research Board (TRB), a semi-autonomous body. The barn aims to improve energy efficiency, cut firewood use and minimise pollution when curing tobacco leaves.
Two years ago, the 57-year-old Giwa built a rocket barn, and proclaims himself impressed by the results.
"Using the standard barn, I needed 15 full scotchcart deliveries (of wood) to treat five bales (of tobacco)," Giwa says. A scotchcart is a two-wheeled, animal-drawn cart common in rural Zimbabwe which can carry up to 550 kg of timber.
With his new barn, Giwa says, just eight cartloads of wood are enough to cure the same quantity of leaves. He earned $4,100 from the sale of 15 bales last year, 10 times as much as he would have got from maize planted on the same area of land.
The barn gets its name from its ability to draw in dry air using exhaust smoke, rather like a rocket which gains its upward thrust from exhaust gases, according to Wisdom Munanga, a TRB engineer. The large diameter of the chimney not only removes smoke from the furnace but also expels moisture from the barn.
Dahlia Garwe, chief executive of the TRB, said the rocket barn is designed to promote high-combustion efficiency, minimising the release of ozone pollutants into the air. As a result, it uses 50-55 percent less fuel wood than conventional barns
Grass insulation 50 mm thick on the higher parts of the barn increases its efficiency by up to 30 percent, she said.
"Due to its smaller surface diameter, the rocket barn uses smaller pieces of firewood, thus making it possible for the farmer to use just branches for curing instead of cutting down the whole tree," Garwe said.
It also improves the quality of the cured leaf, she added. With the old barns, the tobacco leaf would be damaged due to excessive heat from metal pipes. "The rocket barn provides no such risk," Garwe said.
The TRB has distributed rocket barn plans to 10,000 smallholder farmers over the past two seasons at agricultural shows, field days and auctions. Statistics show 60 percent of the farmers who received the plans adopted the barn.
However, the cost of a new barn is a deterrent for some.
Edward Kutsonga, 52, began growing tobacco in 2013. But the farmer from Charumbira Village in Wedza, one of Zimbabwe's major tobacco-growing districts, 150 km southeast of Harare, says it will be a long time before he builds a rocket barn.
"We have not heard much about these barns yet. We do not know how they work, do not have the money, and we are still starting (out)," Kutsonga said.
According to the TRB, a barn can be built for $800-$1,200, including labour. The Forestry Commission says each barn costs up to twice as much as this, but even so, spokesperson Makoto argues that the design "is cost-effective in the long term", in view of its economic and environmental benefits.
The tobacco industry is looking beyond fuel efficiency to other solutions too. In October last year it created the Sustainable Afforestation Association (SAA), committing to spend nearly $35 million planting new forests over the next seven years.
"We aim to minimise deforestation from tobacco," the association's chief executive Maggie Okore said on a recent tour of its new plantation at Rothwell Farm in Zvimba, 60 km west of Harare, where 400 hectares (1,000 acres) of eucalyptus were planted between January and March. The trees will be ready for harvesting in seven years.
This year the SAA plans to plant 4,000 hectares of trees, with an additional 5,000 hectares in each of the five following years, for a total of around 60 million trees.
"However, our projects alone are a drop in the ocean. They will not be able to completely stop deforestation given the extent of forest loss which is fuelled by other factors such as infrastructure development," said Okore, calling for more comprehensive strategies from the central government.
The government passed a law in 2012 restricting the use, trade and movement of firewood. It also requires smallholder tobacco farmers to establish a hectare of fast-growing eucalyptus for every 10 hectares of tobacco grown.
The Tobacco Industry Marketing Board provides free tree seedlings to farmers who buy tobacco seed. On his land, Mickel Giwa began planting trees three years ago, with a hectare of eucalyptus trees to meet future curing needs.
Jeffrey Gogo is a climate change and environmental journalist/columnist with The Herald, Zimbabwe's biggest daily.