Fueling our Future with Weeds

article image
iStockPhoto/Donald Erickson
Russian olive trees are an invasive "weed."

Looking down from an airplane window on a flight from San Jose to Minneapolis, I took note of the very large numbers of tamarisk and Russian olive trees growing along a river in Utah. I’ve seen the same weedy plants up close while flying low in a small plane, and while driving dusty back roads and hiking.

These fast-growing, aggressive invasive species, once colonized, wreak havoc on native, soil-stabilizing grasses, sedges, and wildflowers. By weeds, I don’t mean just dandelions. Think European buckthorn, Russian olive tree, Tree of Heaven (not really very heavenly), and so many other invasive plants. They form dense thickets and stands, and beneath these, produce eroding, nearly bare soils.

The problem is serious, both in ecological and economic terms. For Western cattle ranchers, this colonization reduces their economic returns by curtailing the growth of natural grasses. In the corn belt, these same plants colonize ditch and stream banks, increasing erosion and the flooding of crops. The resulting erosion washes additional sediments and fertilizers into rivers, lakes, wetlands and coastal estuaries, creating algae blooms and dead zones.

But there’s a silver lining in the billions of tons of weedy plants that have colonized our farmlands, ranchlands, floodplain and even urban yards.

Many of these weeds are potentially good sources of biofuel. Biofuel doesn’t have to come from valuable farmland and compete with crop production for feeding our nation and the world. It doesn’t have to come from prime agricultural lands now being used to grow corn to produce biofuels such as ethanol. There are important co-benefits to using weeds, as well: by removing them for biofuel use and replacing them with native species, we can reduce flooding and improve soils, which sequester carbon, mitigating global warming.

The answer to our question appears to be yes. In many locations where dense growths of invasive species are found, it is economically feasible to harvest, process and transport the materials to power plants. In locations where these other conditions can’t be met, the answer can still be yes — with the help of landowners, landscapers and eco-restoration firms.

What is so interesting is that in very large acreages, ecological restoration — putting back into the land what has been taken out of it through years of often onerous agricultural uses, livestock grazing and even forestry practices — can be accomplished simultaneously with the removal and reduction of these invasive woody plants. Restoration results in re-building and protecting remaining soil carbon levels (a lowest-cost climate mitigation strategy, as soil is the second largest carbon sink on the planet next to the oceans), brings back habitat for wildlife, improves land values and reduces flooding.

My colleagues and I at Applied Ecological Services and The Earth Partners are now testing the economic viability of scaling the transformation of weeds into fuel, working with landowners on millions of acres throughout the U.S. and elsewhere. We are exploring the potential of new bioenergy markets and new types of secondary products, including biochar (carbonized wood that can be spread over the land to increase its ability to regrow quickly and improve fertility for future crops, actually putting carbon right back in the soil and growing their storage levels concurrently).

In fact, moving forward, we might take a hint from the plentiful weeds. Perhaps, after these weeds are removed from flood plains, ranches, and many other marginal lands where they currently grow, they can be replaced with native plants in restored landscapes that can then be sustainably harvested for biofuels, while leaving wildlife habitat and water-cleansing lands.

Steven Apfelbaum is chairman and senior ecologist at Applied Ecological Services, Inc., and a managing partner at The Earth Partners, LLC. Apfelbaum is the author of Natures Second Chance (Beacon Press) and co-author with Dr. Alan Haney on Restoring Ecological Health to Your Land (Island Press), which provide a personalized story of restoring their own Wisconsin farm, and a pragmatic national process for restoration of private and public lands.