An expert in permaculture, a renewable agriculture method, will speak Friday at Benicia High School, where he will describe how the principles of the method can be applied from backyards to an entire community.

Toby Hemenway is the author of “Gaia’s Garden: A Guide to Home-Scale Permaculture.”

Benicia Community Gardens launched the Benicia Sustainable Backyard program during its Farm2Family Expo on Sept. 13, where Trathen Heckman, founding executive director of Daily Acts in Sonoma and chair of the board of Transition US, addressed those attending the event.

Hemenway is the second speaker Benicia Community Gardens is bringing to the city to speak on the topic.

The system isn’t new. Australians Bill Mollison and David Holmgren coined the term in 1978 by blending the words “permanent” and “agriculture.”

Mollison has described permaculture as a philosophy “of working with, rather than against, nature; of protracted and thoughtful observation rather than protracted and thoughtless labor; and of looking at plants and animals in all their functions, rather than treating any area as a single product system.”

The two based their concepts on the works of Joseph Russel Smith, who in 1929 wrote “Tree Crops: A Permanent Agriculture.”

In his book, Smith documented his experiments with fruits and nuts as crops for human and animal food.

He recommended planting crops underneath trees, rather than setting up separate gardens and tree groves.

Smith inspired forest farming in Japan and observation-based land use and water management in Australia, as well as other systematic and sustainable methods of agriculture.

Hemenway’s book, “Gaia’s Garden,” has been a best-seller for seven years. It is the 2011 recipient of the Nautilus Gold Medal Award, and in 2009 the Washington Post named it one of the top 10 gardening books of the year.

The author, who describes his approach as ecological gardening, recently revised the book to add a new chapter on urban permaculture.

Hemenway has been an adjunct professor at Portland State University and a scholar-in-residence at Pacific University.

He has taught more than 60 permaculture design courses, presented lectures and workshops at sustainability conferences at major universities, and has contributed to such magazines as Natural Home, Whole Earth Review and American Gardener. He is also the former editor of Permaculture Activist.

Hemenway is a graduate of Tufts University, and originally entered the research field specializing in genetics and immunology.

After discovering permaculture, he changed his career from biotechnology and cultivated a rural permaculture site in southern Oregon.

Hemenway and his wife, Kiel, live in Sebastopol.

He will speak at Friday at Benicia High School’s auditorium. Doors open at 6 p.m.