UNIVERSITY PARK, Pa. — Africa and agroforestry — defined as agriculture that incorporates the cultivation and conservation of trees — are in Penn State professor Michael Jacobson's blood, and the combination has helped shape his career. In turn, the forest economist has played an important role in launching a tree-based biofuel initiative that has major implications for the continent and its millions of subsistence farmers.

At the heart of the effort are croton trees, which seem to grow everywhere in Kenya. Until recently, local people valued them only for the firewood and shade they provide. The ubiquitous croton nuts that the tall, spindly trees produce went to waste. Even animals didn't seem to bother much with them.

But it turns out that croton nuts — about the size of acorns from oak trees common in much of North America — are the source of an oil that can power generators, water pumps and other internal combustion engines and, with processing, can be used in place of diesel fuel in cars and trucks. This previously overlooked tree could be one answer to Africa's growing demand for cheap, low-carbon energy.

"Croton has a lot of potential as a sustainable fuel," said Jacobson, who is involved in several biofuel initiatives in the United States, too. "Croton probably won't become a global biofuel, but if local entrepreneurs persevere and oil prices go up again, it could become a cash crop for local subsistence farmers and become a significant part of east Africa's energy supply."

Jacobson, a native of South Africa, was hired by World Agroforestry Centre to help a small company, Eco Fuels Kenya, or EFK, to survey subsistence farmers in five counties and dozens of villages in Kenya about their willingness to grow croton trees. He asked them such things as how many trees they have, whether they would be willing to plant more, and whether they would gather the nuts and provide them to the company at collection points and, if so, at what price. Essentially, his interviews with hundreds of farmers helped EFK assess its supply chain.

He provided the company with financial models and an overview of potential croton production in Kenya, with a focus on livelihood characteristics of collectors and a description of the business potential. This initial review set the stage for scaling up croton production in Kenya and, later, in surrounding countries in east Africa.

"Although many questions remain across the supply chain, from feedstock to end use of products, my study made a case for scaling up croton production," said Jacobson, who noted that oil is just one product the nuts contain. After oil is extracted, "seed cake" made from the remains of the nuts is a high-protein poultry feed, and the husks can be sold as fertilizer or biofuel. EFK is selling both oil and by-products.

"One of my goals is to try to help struggling African households increase their incomes. Most of them are subsistence farmers, so if we can get them a few more bucks, it's a big deal. To me, a big part of this is about helping local farmers climb out of poverty and improve their lifestyles."

But Jacobson is quick to point out that he is not a social crusader focused solely on helping the poor in Africa. He is involved in other projects internationally and in the United States. The chair of the undergraduate forest ecosystem management program in Penn State's College of Agricultural Sciences, he has worked for 17 years concurrently as an extension specialist in forest finance and taxation, as a researcher, and as a professor teaching classes such as forest economics.

Most of his projects are in Pennsylvania, where he currently is quantifying the impacts of invasive species on forests and investigating riparian buffers for growing biofuels. He just completed a loggers survey for the state's Hardwoods Development Council.

Jacobson, whose family emigrated to the United States in 1977, was stationed in a small village in Lesotho for two years with the Peace Corps in the late 1980s, helping a women's cooperative develop an agroforestry initiative to supplement their incomes. "The men were working in the mines, and the women were learning to spin mohair. I was teaching them that they could sell vegetable plants, fruit-tree seedlings and nitrogen-fixing trees to make extra money," he said.

"I like working in Africa, but my home is here in central Pennsylvania. I have a 50 percent extension, 50 percent teaching and research appointment. But I have found that doing international work informs my teaching and extension activities. My students love it when I teach agroforestry and international forestry and can relate experiences from Africa."

Jacobson is just one of many professors in the College of Agricultural Sciences who is doing international work, according to Deanna Behring, assistant dean and director of international programs for the college. She pointed out that they are making a difference in the world, lending their expertise to improving water quality and quantity, sustainable food production, animal and human health, and developing reliable sources of renewable energy.

"Our faculty members like Mike Jacobson, who are conducting important research and outreach programs around the world, are linking international and domestic perspectives, benefiting their students and clients both here and abroad," she said. "Their work broadly advances the agricultural sciences, addressing some of the most critical challenges facing humans, animals, plants and the environment, making the college's mission a truly global educational endeavor."